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+
+*** START OF THE PROJECT GUTENBERG EBOOK 75985 ***
+
+
+
+
+
+                              HANDBOOK OF
+                              ANÆSTHETICS
+
+                                  BY
+
+                J. STUART ROSS, M.B., CH.B., F.R.C.S.E.
+
+      LECTURER IN PRACTICAL ANÆSTHETICS, UNIVERSITY OF EDINBURGH;
+             HONORARY ANÆSTHETIST EDINBURGH DENTAL SCHOOL;
+              ANÆSTHETIST, DEACONESS HOSPITAL; INSTRUCTOR
+                 IN ANÆSTHETICS, EDIN. ROYAL INFIRMARY
+
+                         With an Introduction
+
+                                  BY
+
+             HY. ALEXIS THOMSON, C.M.G., M.D., F.R.C.S.E.
+
+             PROFESSOR OF SURGERY, UNIVERSITY OF EDINBURGH
+
+                           AND CHAPTERS UPON
+
+                      Local and Spinal Anæsthesia
+
+                                  BY
+
+                   WM. QUARRY WOOD, M.D., F.R.C.S.E.
+
+     LATELY TEMPORARY ASSISTANT SURGEON, EDINBURGH ROYAL INFIRMARY
+
+                               AND UPON
+
+                       Intratracheal Anæsthesia
+
+                                  BY
+
+                 H. TORRANCE THOMSON, M.D., F.R.C.S.E.
+
+                   ANÆSTHETIST TO THE LEITH HOSPITAL
+
+                               EDINBURGH
+                 E. & S. LIVINGSTONE, 17 TEVIOT PLACE
+                                 1919
+
+
+
+
+                               CONTENTS
+
+
+    CHAP.                                                      PAGE
+
+    INTRODUCTION BY PROFESSOR ALEXIS THOMSON                     ix
+
+    PREFACE                                                      xi
+
+        I. PHYSIOLOGICAL ACTION OF ANÆSTHETIC DRUGS               1
+
+       II. SHOCK AND ANÆSTHESIA                                   5
+
+      III. ASPHYXIA OR ANOXÆMIA                                  15
+
+       IV. METHODS OF ANÆSTHETISING                              28
+
+        V. THE CLINICAL OBSERVATION OF THE PATIENT               31
+
+       VI. THE PREPARATION OF THE PATIENT                        42
+
+      VII. NITROUS OXIDE                                         46
+
+     VIII. NITROUS OXIDE AND OXYGEN                              60
+
+       IX. ETHER                                                 74
+
+        X. INTRATRACHEAL ETHER                                   96
+
+       XI. CHLOROFORM                                           109
+
+      XII. ETHYL CHLORIDE                                       122
+
+     XIII. MIXTURES OF NITROUS OXIDE AND ETHYL CHLORIDE         128
+
+      XIV. MIXTURES OF CHLOROFORM AND ETHER                     134
+
+       XV. SEQUENCES                                            137
+
+      XVI. THE ACCIDENTS OF ANÆSTHESIA                          140
+
+     XVII. THE SEQUELÆ OF ANÆSTHESIA                            151
+
+    XVIII. POSTURE OF THE PATIENT                               157
+
+      XIX. THE CHOICE OF THE ANÆSTHETIC                         162
+
+       XX. LOCAL ANÆSTHESIA                                     171
+
+      XXI. SPINAL ANÆSTHESIA                                    193
+
+    APPENDIX                                                    201
+
+    INDEX                                                       209
+
+
+
+
+                        LIST OF ILLUSTRATIONS.
+
+
+    FIG.                                                          PAGE.
+
+     1. Shock (Grey and Parsons)                                      6
+
+     2. Shock (after Crile)                                           8
+
+     3. Diagram to Illustrate Anoci-Association (after Crile)        11
+
+     4. Apparatus for Lane’s Saline Infusion                         13
+
+     5. Diagram of the Vicious Circle of Asphyxia                    20
+
+     6. Hewitt’s Mouth Props                                         22
+
+     7. Bellamy Gardner’s Mouth Props                                23
+
+     8. Phillips’ Modification of Hewitt’s Artificial Air-way        23
+
+     9. Silk’s Nasal Tubes                                           23
+
+    10. Tongue Forceps and Glossotilt                                24
+
+    11. Apparatus for Opening Clenched Jaws                          25
+
+    12. Frame for Adapting Vertical Cylinders to Foot Use            47
+
+    13. Nitrous Oxide Cylinders (upright and angle)                  48
+
+    14. Complete Nitrous Oxide Apparatus                             49
+
+    15. Barth 3-way Nitrous Oxide Tap                                50
+
+    16. Hewitt’s Wide-bore Nitrous Oxide Valves                      50
+
+    17. Ash’s Modification of Paterson’s Nasal Gas                   58
+
+    18. Hewitt’s Apparatus for Nitrous Oxide and Oxygen              63
+
+    19. Diagram to Illustrate Action of Hewitt’s and Teter’s
+          Gas-Oxygen Methods                                         67
+
+    20. Details of Clark’s Expiratory Valve                          68
+
+    21. The Clarke Gas-oxygen Apparatus                              69
+
+    22. Marshall’s Sight-feed Gas-oxygen Apparatus                   70
+
+    23. Clover’s Ether Inhaler, with Nitrous Oxide Attachment        77
+
+    24. Clover’s Inhaler, Diagram of a Vertical Section              78
+
+    25. Hewitt’s Wide-bore Ether Inhaler                             80
+
+    26. Ormsby’s Ether Inhaler                                       81
+
+    27. Bellamy Gardner’s Mask and Ether Dropper                     83
+
+    28. Four Photographs to Illustrate the Administration of Open
+          Ether                                                    84–5
+
+    29. Shipway’s Warmed Ether Apparatus                             91
+
+    30. Diagram of Intratracheal Apparatus                           98
+
+    31. Electric Blower for Intratracheal Method                     99
+
+    32. Kelly’s Intratracheal Apparatus                             100
+
+    33. Shipway’s Intratracheal Apparatus                           102
+
+    34. Hill’s Direct Laryngoscope                                  104
+
+    35. Diagram of Blood-pressure Curves Obtainable with
+          Chloroform                                                110
+
+    36. Vernon Harcourt’s Percentage Chloroform Inhaler             115
+
+    37. Chloroform Mask                                             116
+
+    38. Chloroform Drop Bottles                                     117
+
+    39. Junker’s Chloroform Apparatus                               119
+
+    40. Tube of Ethyl-Chloride                                      122
+
+    41. Ethyl-Chloride Inhaler                                      124
+
+    42. Guy’s Gas and Ethyl-Chloride Inhaler                        128
+
+    43. Details of Guy’s Inhaler                                    129
+
+    44. Diagram of Gas-Oxygen Method Introduced by Dr Guy and
+          the Author                                                130
+
+    45. The Guy Ross Gas-Oxygen Instrument                          131
+
+    46. Rendle’s Cone                                               135
+
+    47. Clover Inhaler adapted for the Ethyl Chloride-Ether
+          Sequence                                                  139
+
+    48. Two Photographs illustrating Sylvester’s Artificial
+          Respiration                                             146–7
+
+    49. Sitting-up Posture for Operations upon the Head and Neck    159
+
+    50. O’Malley’s Posture for Intra-nasal Surgery                  160
+
+    51. All-metal Syringe for Infiltration Anæsthesia               176
+
+    52. Infiltration of the Brachial Plexus                         183
+
+    53. Needle and Syringe for Spinal Analgesia                     194
+
+    54. Position of the Patient for Spinal Analgesia                196
+
+
+
+
+                             INTRODUCTION.
+
+
+The securing of a safe anæsthesia during operations is more important
+than ever before, partly because of the mere number of operations,
+and partly because of the greater extent to which other operative
+risks--hæmorrhage, shock and infection--have been overcome. The risk
+from the anæsthetic is now so very small that the joint aim of the
+surgeon and anæsthetist to abolish it altogether is not far from
+being accomplished. The author of this volume has done a good deal to
+accomplish this end, and it is a matter of congratulation that he has
+now published an account of his methods, so that a larger circle may
+benefit from his teaching and his experience.
+
+The author very properly goes further and maintains that anæsthesia
+must not only be safe but must also be good; good anæsthesia is
+absolutely vital to good surgery. Only a generation back many surgeons
+professed to see no difference as to who gave the anæsthetic; at the
+present day no one willingly embarks upon a difficult operation without
+the aid of a skilled anæsthetist.
+
+In various parts of the book the author has very rightly laid great
+emphasis upon the influence which the work of the surgeon has upon
+that of the anæsthetist. The latter may learn much from an occasional
+glance at the field of operation. He should not interest himself in the
+details of operative procedure to the distraction of his mind from his
+own responsibilities; but he can, in abdominal surgery, see for himself
+whether the muscles are properly relaxed, and observe the state of
+operation, so that he can when necessary deepen the anæsthesia in good
+time, while not maintaining deep anæsthesia when a light one would
+suffice. Finally, he can check his other sources of information as to
+the condition of the circulation by noticing the force with which cut
+arteries spout, the colour of the blood and the size of uncut veins.
+
+Like other branches of medicine, adequate study as well as practical
+experience is required in order to master the art of administering
+anæsthetics, and that a reliable manual of instruction is essential,
+goes without saying; I feel on perfectly safe ground in recommending
+this book as such both to the student and the practitioner.
+
+                                                        ALEXIS THOMSON.
+
+
+
+
+                               PREFACE.
+
+
+This little book is an attempt to present to the student and
+practitioner a condensed account of modern anæsthetic views and
+practice. In choosing a general scheme I have tried to lay emphasis
+upon the relation of anæsthesia to general medical science rather than
+upon elaborate descriptions of anæsthetic apparatus and methods which
+a few years hence may be superseded. I have therefore devoted the
+first four chapters to an account of the various forces which modify
+the physiology of the patient during an operation under a general
+anæsthetic, in so far as we at present understand them. I trust that
+they will prove not only a sound basis for the information given in
+the rest of the book but also a help towards forming a judgment upon
+new methods and appliances as and when they meet the attention of the
+reader.
+
+In making a selection of drugs and appliances for description, I have
+eliminated those which do not appear to me to have any real sphere of
+usefulness.
+
+The account of nitrous oxide and oxygen has been given in some
+detail. Both the profession and the lay public have arrived, through
+the experiences of the war, at a more just appreciation of the
+possibilities of this combination than was at all general before
+the year 1914. At the present day, no one who proposes to engage in
+anæsthetic work can afford to remain unpractised in its administration.
+
+I have an apology to make to my women readers. Throughout the book,
+when speaking of the anæsthetist, I have presumed the male sex. Such
+phrases as “his or her” and “he or she” are tedious and inelegant, and
+their omission must not be taken as forgetfulness on the author’s part
+that women frequently make very good anæsthetists.
+
+Professor Alexis Thomson has added to the many kindnesses I have
+received at his hands by writing the Introduction which immediately
+precedes this Preface, and I wish to express my sincere thanks to him
+for such a valuable addition to the book.
+
+From Mr David Wallace, F.R.C.S.E., I have received much valuable help
+and guidance in anæsthetic matters. It was largely due to his kindly
+assistance and moral support that I was encouraged to persevere with my
+early attempts to use nitrous oxide and oxygen in major surgery. The
+hints which are given in connection with Genito-Urinary Surgery are
+also derived from him.
+
+The chapters upon Local and Spinal Anæsthesia are entirely the work of
+Mr Wood, to whom I must express my gratitude for the admirable way in
+which he has done the work.
+
+I must also thank Dr Torrance Thomson most sincerely for his useful
+contribution in chapter X, which constitutes a complete
+monograph upon Intratracheal Anæsthesia.
+
+To Dr Wm. Guy I am indebted for the photographs which appear in the
+book, and I must express my sincere gratitude to him for the trouble he
+has taken in the matter.
+
+Much thanks are also due to the following firms who have been kind
+enough to lend illustrative blocks:--Messrs Claudius Ash & Co. Ltd., G.
+Barth & Co., De Trey & Co., J. Gardner & Son, Allen & Hanbury’s Ltd.,
+Meyer & Phelps, Coxeter & Son, Down Bros., Ltd., Krohne & Sesemann, and
+Mr J. H. Montague.
+
+Lastly, I must express my high appreciation of the courtesy which the
+publishers have shown to me, and of their generosity in the matter of
+illustrations.
+
+                                                        J. STUART ROSS.
+
+   _October 1919._
+
+
+
+
+                       Handbook of Anæsthetics.
+
+
+
+
+                              CHAPTER I.
+
+               PHYSIOLOGICAL ACTION OF ANÆSTHETIC DRUGS.
+
+
+Every anæsthetic drug has certain pharmacological peculiarities of its
+own, but all have much in common, and it is to these common features we
+shall first direct our attention.
+
+Reaching the blood stream by absorption from the lung alveoli, the drug
+enters into loose combination with the red blood corpuscles; a small
+proportion only is carried in the plasma. Within the corpuscles it
+must of necessity displace a certain proportion of the oxygen normally
+carried: this factor is of great importance only in the case of nitrous
+oxide gas, which readily displaces the larger part of the normal oxygen
+content. In the case of other anæsthetics, the same process occurs; but
+to a less extent. Detailed figures of the extent to which the blood
+gases are altered in various stages of chloroform anæsthesia will be
+found in Appendix III.
+
+The actions of individual drugs upon the circulatory, respiratory,
+and excretory systems differ so considerably that a small section
+has been devoted to this subject in each of the chapters devoted to
+nitrous oxide, ether, and chloroform respectively. One feature is,
+however, dependent upon the _state of anæsthesia_ rather than
+the action of the particular drug, and that is a certain slight fall
+of blood pressure. This phenomenon is seen even in natural sleep, and
+is presumably due simply to lack of normal stimuli such as tactile,
+visual, and auditory impressions which in the ordinary circumstances of
+life, help to maintain the tone of the vasomotor system. That such a
+fall is due to the _state_ of anæsthesia admits of little doubt,
+but the fact is not always easy to demonstrate since each of the drugs
+themselves have a marked influence upon the B.P., which masks the pure
+effect of the anæsthetic sleep.
+
+
+                    Action upon the Nervous System.
+
+It is in this system, of course, that we look for the characteristic
+action of anæsthetics, since if we had a choice, it is the brain
+only which we should desire to influence by our drug. It used to be
+said that anæsthetics paralyse the brain from above downwards, but
+that is only approximately true. More correctly we may say that the
+more highly developed parts of the brain are earliest affected, and
+that those portions, such as the vital medullary centres, which man
+shares in common with his humbler zoological relatives, maintain
+their activity until the last. Moreover, it must be remembered that
+before any brain centre succumbs, it passes through a preliminary
+stage of _excitement_, varying in intensity with varying drugs
+and also with different types of patients. Those who are accustomed
+to administer to their nervous centres repeated large doses of such
+nerve poisons as alcohol and tobacco, may show very evident signs of
+this preliminary cerebral irritation during the process of induction
+of anæsthesia; so do also the unhappy possessors of nervous systems
+deranged from other causes such as epilepsy.
+
+_The first centres to be attacked are those of thought and perception._
+The patient is incapable of coherent reasoning, and loses touch to
+some extent with impressions from the outside world. _Muscular sense
+and co-ordination next become affected._ Although still able to move
+the limbs or the head, movements are incoherent, and if at this stage
+the patient were put upon his feet, he would stagger as he does in
+alcoholic intoxication. By this time _sensation_, both tactile and
+special, begins to be affected. The patient is no longer cognisant of
+pain,--if cut he would at any rate not have a remembrance of pain.
+_The special senses_ are at this stage also lost, one of the last to
+go being the auditory sense, a point which is sometimes forgotten by
+those inclined to talk while anæsthesia is being induced. _Muscle tone
+is the next function_ to be lost, and at this stage all movements on
+the part of the patient should cease except those of respiration. _The
+reflexes_ disappear at varying stages: the spinal reflexes, _e.g._
+the knee-jerks, disappear fairly early, probably before muscle tone
+is entirely abolished, but certain other reflexes persist to a later
+stage. Those which are of most interest to the anæsthetist are the
+conjunctival, corneal, and pupillary reflexes of which he will find
+full details in Chapter V.
+
+Lastly the _vital medullary centres_, respiratory, vasomotor, and
+cardiac are overcome, and at this stage we have passed beyond the
+stage of a proper anæsthesia into that of over-dosage. In passing it
+may be observed that the level at which one endeavours to work is that
+indicated by the loss of muscle tone and of some of the reflexes and
+the full activity of the medullary centres, and that an anæsthetic is
+good or bad according as it gives a wide or narrow margin between these
+two events.
+
+Upon the _peripheral nerves_, anæsthetics have much less effect than
+on the central nervous system. Faradisation of a _motor nerve_ will
+in the deepest anæsthesia still cause immediate contraction of the
+muscles supplied by it, showing that the conductivity of the nerve
+is unaffected. Of far more importance, however, is the fact that
+the _sensory nerves_ are not paralysed. That pain is not felt by
+the patient is due simply to the loss of function of the cerebral
+sensory centres; _injury to the nerve still causes an impulse to be
+transmitted to the brain_. Since no operative procedure can be carried
+out without more or less trauma (injury) to sensory nerves, we may
+picture the brain of the patient undergoing a surgical operation while
+under a general anæsthetic, as being constantly bombarded by sensory
+stimuli, which though not consciously appreciated by the sleeping
+patient, are yet capable of producing reflex effects of a definite
+character, the importance of which to the work of the surgeon and
+anæsthetist it is difficult to exaggerate, and of which a condensed
+account will be found in the succeeding chapter.
+
+
+
+
+                              CHAPTER II.
+
+                         SHOCK AND ANÆSTHESIA.
+
+
+Under this short and convenient title, the author proposes to discuss
+all the changes observable in the patient’s condition, the causation
+of which can be traced to the procedure of the surgeon. The use of
+the term _shock_ was at one time, and by some teachers still is,
+restricted to a definite clinical condition. The patient was described
+as lying pallid and almost pulseless, with dilated pupils, cold
+sweating skin, and gasping, irregular respirations. In the view more
+generally taken to-day, that is but the extreme and final manifestation
+of a syndrome, which any patient who suffers trauma (whether inflicted
+accidentally or by the surgeon) exhibits in a greater or less degree,
+and from which general anæsthesia protects a patient to a very limited
+extent only.
+
+Professor Crile, to whose work we owe so much of our knowledge on this
+subject, has said, “In general anæsthesia, part of the brain only is
+asleep.” Though consciousness is abolished, many parts of the brain
+are quite capable of responding to _centripetal impulses_ passed
+to the brain through sensory nerves injured by the knife. A full
+account of the changes demonstrated by Crile in some of the cells of
+the grey matter of the brain as a result of such stimuli, and of the
+interpretation put upon these by their discoverer, is not suitable for
+a text-book of anæsthesia. It is sufficient to say that such changes
+have been discovered, and that their occurrence as a result of trauma
+is not prevented by inhalational anæsthesia. Such changes, though of
+the utmost interest scientifically, cannot be demonstrated clinically,
+and it is to alterations of _blood pressure_ and of _respiration_ that
+we must look for clinical evidence of the effects of _shock stimuli_.
+
+  [Illustration:
+
+   FIG. 1.--Shock--Blood pressure of a dog undergoing
+   laminectomy under general anæsthesia (Grey and Parsons.)
+
+  (_Reproduced by kind permission of the Authors._)]
+
+With every incision by the surgeon, sensory nerve twigs are of
+necessity injured. The fibres found in sensory nerves are, it will
+be remembered, either pressor, or depressor--that is, stimulation of
+them, causes either an increase or decrease of the blood pressure,
+the depth and frequency of respiration being usually affected in the
+same direction as the B.P. That such changes do commonly occur is
+easily recognised by clinical observation. The veriest beginner in
+anæsthesia soon learns to expect a deeper, quicker respiration and a
+stronger pulse as soon as the operation has begun. These changes have
+been studied experimentally upon animals and upon the human subject by
+the use of the sphygmomanometer: Fig. 1, drawn from Grey & Parson’s
+Arris and Gale Lectures of 1912, shows a tracing from a dog undergoing
+laminectomy under general anæsthesia, and gives a good idea of the
+early evidences of shock.
+
+       *       *       *       *       *
+
+We may condense the results of much work on this subject under the
+following headings:--
+
+   (_a_) Most stimuli from the field of operation cause a
+   sharp rise of blood pressure, followed by a sharp fall.
+
+   (_b_) Successive stimuli delivered quickly one after
+   another add their effects together, the total result being
+   considerably greater than from one severe trauma.
+
+   (_c_) After a time, the pressor effect of stimuli begins
+   to lessen: the animal or patient “wears out,” and finally no
+   pressor result can be obtained by the most massive stimulation:
+   the curve of B.P. steadily falls: the condition of full surgical
+   shock is produced.
+
+   (_d_) The tearing or pulling of tissues produces more
+   powerful stimuli than the use of a sharp knife, and, therefore,
+   brings on the full condition of shock more rapidly.
+
+   (_e_) Stimuli from some tissues cause much more reflex
+   effect upon the organism than from other less sensitive
+   structures. This is well exemplified when an abdominal section
+   is in progress. Incision of skin causes immediate response in
+   deepened respiration and higher B.P.: division of the fascia
+   very little effect. If the muscle is divided by the knife, again
+   little reflex effect is noticeable, but if it be stretched and
+   split by the fingers, the response is powerful. The parietal
+   peritoneum, however delicately handled, is one of the most
+   sensitive structures in the body, and, unless the patient is
+   fully under at the stage either of opening or closing this
+   layer, actual breath-holding or straining will occur. On the
+   other hand, incision or suture of the hollow viscera will cause
+   practically no response however light the anæsthesia, provided
+   these structures, and their connections with the parietes, are
+   not pulled upon.
+
+   (_f_) Stimulation of certain selected areas, of which the
+   spermatic cord is a well-known but by no means the only example,
+   results in an almost immediate fall of blood pressure with
+   little or no preliminary rise. In the operating theatre, we
+   sometimes see faintness or syncope arising quite suddenly during
+   operations in such regions. This subject is explained more fully
+   in Chapter XVI. under the term “Reflex Syncope.”
+
+  Illustration:
+
+    FIG. 2.--Combined blood pressure chart showing
+    the average of a number of experiments.--A--Under nitrous
+    oxide and oxygen. B--Under ether. At each spot marked
+    x, a trauma (burning of the paw) was inflicted. (After
+    CRILE.)]
+
+   (_g_) While no general anæsthetic protects absolutely
+   from shock stimuli, some anæsthetics give more protection than
+   others. Nitrous oxide is the most effective in this respect,
+   its powers being two and a half times greater than that of
+   ether: chloroform is even less effective than ether (_see_
+   Fig. 2).
+
+   (_h_) The claim made by the older generation of surgeons
+   that shock could be prevented by the use of a _deep_
+   anæsthesia, and that the occurrence of any “Reflex syncope” was
+   always a sign of too light an anæsthesia cannot be made good. At
+   the same time, it must be admitted that too light an anæsthesia
+   does increase the likelihood of shock. _Prolonged deep_
+   anæsthesia, on the other hand, produces by itself a condition
+   indistinguishable from shock, with the single exception of
+   nitrous oxide gas.
+
+   (_i_) Operative shock is predisposed to by several factors
+   of which the following are the most important:--
+
+      1. Hæmorrhage before or during operation.
+
+      2. Sepsis.
+
+      3. Fear.
+
+      4. Prolonged starvation.
+
+      5. Certain diseases, especially hyperthyroidism
+      (exopthalmic goître).
+
+
+                          Theories of Shock.
+
+So far as we have touched in the above upon theory, it has been theory
+which receives general acceptance and which accords with known clinical
+facts. When we come to discuss _the reason why blood-pressure falls
+in shock_, we are in more debatable country.
+
+Crile’s original view was that the upstroke seen in such charts as
+shown in Fig. 1 are caused by reflex vaso-constriction, and that the
+final fall of B.P. was due to exhaustion of the vaso-motor centre.
+This view he does not seem to have modified as a result of his later
+discovery of degenerative changes in certain cells of the grey matter
+of the brain.
+
+Other workers, J. D. Malcolm in this country, and Yandell Henderson,
+of Yale, U.S.A., maintain an opinion diametrically opposite. In their
+view, in fully developed shock, the vessels are in vaso-constriction,
+and the circulation is arrested from undue internal resistance to blood
+flow.
+
+A third explanation of lowered B.P. has been offered, and while its
+significance is not understood, there is fairly general agreement as
+to its validity. This factor is a _reduction in the total blood
+volume_--an oligæmia. No one has as yet demonstrated to what region
+or organ the missing blood volume has retreated.
+
+
+             YANDELL HENDERSON’S ACAPNIC THEORY OF SHOCK.
+
+Acapnia is a condition in which the CO_{2} content of the blood and
+tissues has been brought to too low a level. Those who climb mountains
+suffer from it, and so do those who breathe rapidly and heavily for a
+prolonged period. Carbon dioxide is necessary for the vigour of the
+respiratory centre, of which it may be termed the natural regulator.
+Moreover, the heart and the great veins which empty into it require a
+certain proportion of CO_{2} in the blood.
+
+Admittedly, patients inhaling anæsthetics do on occasion breathe too
+deeply. Sometimes they do so voluntarily before losing consciousness,
+sometimes reflexly as a result of such a manœuvre as stretching the
+sphincter ani. Do they thereby bring their CO_{2} down to a level which
+does serious harm and which can be considered a cause of collapse under
+anæsthesia? Henderson says they can and do: most other workers deny the
+possibility.
+
+  [Illustration:
+
+  FIG 3.--Diagram (after CRILE) to illustrate
+  anoci-association. In “A” the trauma is inflicted on the leg,
+  and the brain being wholly unprotected, considerable shock
+  is suffered. In “B” the brain is protected by inhalational
+  anæsthesia from the effects of fear, etc. In “C” the sensory
+  nerves from the seat of trauma are blocked by novocaine,
+  and the brain also protected by inhalational anæsthesia.
+  Theoretically no shock is suffered.]
+
+
+                  Prevention and Treatment of Shock.
+
+There are many theories of shock but only one anti-shock technique
+which will bear examination. Founding upon his own theory, Crile about
+1913 elaborated his ANOCI-ASSOCIATION method of which the
+following are the leading features (_see_ Fig. 3):--
+
+   (_a_) _Prevention of fear._--Every member of this team is taught
+   the all-important art of so dealing with the patient that no
+   unnecessary fear is allowed to remain in his mind. That art does
+   not consist in endless repetition of the phrase, “Do not be
+   frightened,” but rather in each so bearing himself or herself
+   before the patient that he may gradually acquire the conviction
+   that he is surrounded by careful, kindly, and skilful persons
+   who are doing for him what they do for hundreds of others, and
+   doing it with an expectation of his early and complete recovery
+   so certain that they do not need to put it into words unless
+   definitely questioned. Such an art is not acquired in a day, and
+   some unhappy few are so constituted that they can never acquire
+   it.
+
+   As a further preventative of fear, and also for other reasons
+   explained in Chapter vi., the patient receives a dose of morphia
+   (⅙th grain, with ¹⁄₁₂₀th grain atropine, hypodermically) three
+   quarters of an hour before operation. Some surgeons go further,
+   and give a sedative the night before operation. Veronal gr.
+   viii. is the favourite prescription of Prof. Alexis Thomson of
+   Edinburgh.
+
+   (_b_) The sensory nerves are “blocked” by infiltration with
+   novocain. By the systematic use of local in conjunction with
+   general anæsthesia, the harmful stimuli from the area of
+   operation are prevented from reaching the brain. For the details
+   of this measure, the reader is referred to Chapter xx.
+
+   (_c_) The anæsthetic of choice in Crile’s practice is nitrous
+   oxide and oxygen (_see_ Chapter vii.).
+
+The whole of this technique has not been generally adopted as a
+routine, but nevertheless the teachings of Crile have greatly
+influenced the mind and practice of most surgeons and anæsthetists.
+Traces of that teaching are to be found everywhere in the organisation
+built up during the Great War to save as many as possible of the lives
+of badly smashed men. At no previous time in the history of surgery was
+the problem of shock so pressing, and a brief resumé of the methods
+adopted is here set down, as an example of how shock should be dealt
+with.
+
+  [Illustration: FIG. 4.--Lane’s apparatus for
+  subcutaneous infusion of saline solution.]
+
+
+          Treatment of Shock among the Casualties of the War.
+
+The first essentials demanded were the most careful organisation, the
+provision of equipment far in advance of most home civilian hospitals,
+and of surgical teams specially trained to a high level of excellence.
+Upon recovery from the field, the injured man received at the ADVANCED
+DRESSING STATION, such first aid dressing as was necessary, and a
+substantial dose of _morphia_. When the latter had had time to take
+effect, the case was passed back to the Field Ambulance (where he
+received his first dose of antitetanic serum), and from there to the
+CASUALTY CLEARING STATION. During every stage of the journey, he
+received as much _warm fluid nourishment as possible_. Arrived at
+the C.C.S., the severe case was passed first into the RESUSCITATION
+WARD. This department, under the charge of a specially trained M.O.,
+concentrated largely upon two measures--the thorough _warming_ of the
+patient, and the replacing as far as possible of the fluids lost to
+him by hæmorrhage and shock. The warming in many C.C.S.’s was effected
+by electric radiant heat baths. The fluids were replaced either by
+way of infusing blood from another patient, or by the use of _gum
+saline solution_. Introduced into a vein, the action of this solution
+persists for a much longer period than that of ordinary saline, being
+less easily lost by osmosis through the capillaries into the tissues.
+From the resuscitation ward, the patient passed to the OPERATING
+THEATRE. Though the full technique of anoci-association was not always
+possible, the maxims which Crile had sought to inculcate into the
+practice of surgery influenced the work of surgeons and anæsthetists
+very profoundly. Nitrous oxide and oxygen was used for all the severely
+shocked cases, and infiltration with local anæsthetics where feasible
+and necessary.
+
+
+                   Subcutaneous Infusion of Saline.
+
+For those who do not feel bound to adopt the Crile technique this is a
+simple measure which does much to minimise shock in prolonged abdominal
+operations. Saline infusion into a vein is so rapidly excreted that its
+influence is very fugacious, but if the fluid be introduced under the
+skin during the period of operation it is slowly absorbed as required
+by the blood. Sir Arbuthnot Lane is a strong advocate of this measure.
+
+Fig. 4 shows a suitable apparatus. The needles are thrust into the
+loose areolar tissue under the breast, one on each side, and a pint or
+more of fluid is _slowly_ run in from the reservoir.
+
+
+
+
+                             CHAPTER III.
+
+                         ASPHYXIA OR ANOXÆMIA.
+
+
+Some degree of asphyxia is a common complication of inhalational
+anæsthesia: indeed some small degree of it is almost unavoidable. It
+is hardly too much to say that the difference between a good and a bad
+anæsthetist is that the one recognises and deals with asphyxia in its
+early stages, while the other allows it to assume serious proportions
+before he becomes aware of its existence. The man who only realises
+that asphyxia is present when the patient is deeply cyanosed and has
+ceased to be able to draw any air at all into his chest may know much
+of the physiology of anæsthetic drugs, and be well up in complicated
+anæsthetic apparatus, but knows nothing of the proper practice of
+anæsthesia.
+
+Asphyxia arises during anæsthesia from several causes. In the first
+place, the drug which the patient is inhaling and absorbing into the
+blood, turns out from his red corpuscles a corresponding quantity
+of oxygen. While this is only seen in its extreme form in the case
+of nitrous oxide gas, it is a factor acting even in the case of
+other anæsthetics. Secondly, during deep anæsthesia, the respiratory
+centre may be somewhat depressed, and the force and frequency of the
+respiratory act diminished. Thirdly, the respiratory passages may be
+partially or wholly occluded from _mechanical_ causes. This is far
+the most important type of asphyxia, being the most common, the most
+fatal, and the most easily prevented.
+
+
+                 Common Causes of Mechanical Asphyxia.
+
+(1) CLENCHING OF THE JAWS arises not uncommonly during anæsthesia,
+being specially frequent towards the end of the induction period.
+Since a very large proportion of individuals have nasal passages
+insufficient in bore to carry the full volume of respired air,
+respiration must be obstructed if the jaws are clenched.
+
+(2) FALLING BACK OF THE LOWER JAW AND BASE OF THE TONGUE OVER THE
+EPIGLOTTIS.--This is always liable to happen after the muscles are
+deeply relaxed.
+
+(3) MUCOUS OR BLOOD OR A FOREIGN BODY IS DRAWN BY INSPIRATION INTO
+THE AIR PASSAGES.--Changes of position of the head may release
+mucous which has been gathering in some parts of the mouth or pharynx.
+For instance, if the head has been lying on the side for some time, a
+pool of mucous or saliva commonly gathers in the most dependent cheek,
+and unless this is mopped out before the head is brought into the
+mesial position, this pool will be suddenly tipped backwards, and very
+probably drawn into the larynx. Again, in operations upon the nasal or
+oral cavities, blood is always liable to be inspired, and not a few
+teeth have found their way into the air passages in the practices of
+dental surgeons who do not take precautions against this accident.
+
+(4) SPASM OF THE ADDUCTORS OF THE VOCAL CORDS is one of the most common
+and most baffling incidents in anæsthesia. It announces its presence by
+the commencement of _laryngeal stridor_, a high-pitched crowing noise,
+which is as annoying for the surgeon and anæsthetist to hear as it is
+detrimental to the progress of a smooth anæsthesia. Inspired mucous or
+blood almost invariably sets it up, and the two conditions of fluid
+in the larynx and narrowing of the glottis from approximation of the
+cords, add their effects together, with resulting obstruction of a high
+degree.
+
+Laryngeal stridor, however, frequently occurs even when no fluid
+has been inspirated. It may be set up as a reflex from the area
+of operation. Dilatation of the sphincter ani, and removal of the
+prepuce in circumcision, are two common examples of this. It is also
+undoubtedly sometimes caused by giving too strong a vapour during the
+latter part of the induction stage. Stridor unfortunately sometimes
+occurs from no obvious cause at all, or to speak more correctly,
+from causes which are at present not known to us. It is the author’s
+belief that one of these causes may prove to be _morphia_ given as a
+preliminary to inhalational anæsthesia. In his experience, stridor
+has been more frequent with morphia than without, particularly if
+chloroform be the anæsthetic chosen. Beyond that he cannot at present
+go.
+
+(5) PRESSURE UPON THE AIR PASSAGES OF NEOPLASTIC OR INFLAMMATORY
+SWELLINGS IN THE NECK.--In such cases any obstruction which may
+exist before induction will probably become intensified during the
+process, and a complete arrest of respiration is not uncommon. Large
+goîtres are the most common type of neoplasm to give trouble, and all
+acute inflammatory conditions in the neck which extend towards the
+trachea are notorious for their tendency to give cause for anxiety
+during anæsthesia.
+
+
+                      The Physiology of Asphyxia.
+
+An animal, subjected to asphyxia, either mechanically or otherwise,
+shows the following signs:--
+
+   (_a_) _Increase of the force and frequency of the
+   respiratory movements of chest and abdomen._ Even though
+   there be a complete mechanical obstruction, increased efforts
+   to breathe will still be made for some moments, although air no
+   longer passes in and out of the chest.
+
+   (_b_) There is a considerable rise of blood pressure owing
+   to a high degree of vaso-construction.
+
+   (_c_) The pupils dilate.
+
+   (_d_) Generalised convulsions.
+
+   (_e_) The animal succumbs finally from cardiac failure.
+   No heart muscle can continue to function properly if supplied
+   by the coronary arteries with venous blood. Moreover, the
+   heart pump has to act against the greatly increased peripheral
+   resistance induced by vaso-constriction. It must therefore be a
+   matter of time only when the strongest and healthiest heart will
+   cease to contract under the abnormal conditions of asphyxia.
+
+There are in asphyxia, two alterations in the blood-gasses, _i.e._
+lack of oxygen and increase of CO_{2}. The action of these two
+conditions have been differentiated by experimental work (Starling,
+Kayala, Jerusalem), and one can say definitely that the excess of
+CO_{2} is the cause of the increased activity of the respiratory
+efforts, and that the remaining phenomena are due to oxygen starvation.
+This point is of some importance in considering anæsthetic methods
+in which re-breathing (breathing in and out of a bag) is practised.
+The use of such methods has often been thoughtlessly condemned as
+“poisoning the patient with his own CO_{2}.” Within the limits usually
+practised, a re-breathing method does not involve any such risk,
+provided oxygen starvation does not occur. This point is referred to
+again in Chapter iv.
+
+
+  Clinical Signs of Mechanical Asphyxia in the Anæsthetised Subject.
+
+The classical signs of asphyxia above described are hardly to be
+expected in the operating theatre, but essentially the condition
+of the patient who develops respiratory obstruction while under an
+anæsthetic is similar to that produced experimentally in animals in the
+laboratory. The changes most easily observed are as follows:--
+
+   (1) _Alteration of the colour._--Cyanosis shows itself earliest
+   in the lips, and the lobules of the ears,--later the whole face
+   becomes dusky.
+
+   (2) _Dilatation of the pupil_, which ceases to respond to the
+   stimulus of light.
+
+   (3) _The respiratory movements increase in depth and
+   frequency._--The chest and abdominal walls heave forcibly; but
+
+   (4) _The volume of air passing in and out of the glottis is
+   diminished._--In complete obstruction, of course, none passes
+   at all. In passing we may draw the moral that persistence of
+   chest movements is no proof of the passage of air in and out
+   of the chest: that can only be proved by hearing the movement
+   of air through glottis and mouth or nose, or feeling it on the
+   delicate skin of the back of the observer’s hand.
+
+   (5) _True convulsions are not seen_, unless we may consider
+   the jactitation of deep N_{2}O anæsthesia as such (see Chapter
+   VII.). Nevertheless, there are obvious and most valuable signs
+   of asphyxia to be found in the muscular system often quite
+   early. These consist in the incidence of _muscular rigidity_,
+   which is frequently observed first in the muscles of the
+   abdominal wall. A surgeon performing laparatomy will notice
+   at once the occurrence of this phenomenon, than which hardly
+   anything can complicate and delay his task more effectively.
+   The anæsthetist who knows his work will, upon hearing from the
+   surgeon a complaint as to the rigidity of the abdominal wall,
+   devote his attention first to securing a perfectly free air-way
+   before deciding that a deeper anæsthesia is required.
+
+  [Illustration: FIG. 5.--Vicious circle of asphyxia.]
+
+
+                 Prevention and Treatment of Asphyxia.
+
+Once asphyxia, especially mechanical asphyxia, has begun, it almost
+invariably tends to get worse. The engorgement affects among other
+venules, those which run under the mucous membrane of the respiratory
+tract, still further obstructing the passage of air. The muscular
+rigidity, moreover, soon manifests itself in the adductors of the
+vocal cords and the muscles which close the jaws: the patient has
+thus entered into a “vicious circle,” Fig. 5. It is evident that the
+prevention of the earliest signs of asphyxia is to the anæsthetist a
+matter of vital interest. The cardinal points to watch are as follows:--
+
+   (1) Keep the neck of the patient as far as possible in a natural
+   position, _i.e._ do not either flex or extend the head unduly
+   upon the body unless the nature of the operation demands such an
+   unusual position.
+
+   (2) Maintain a free passage for air either through the nose or
+   the mouth.
+
+   (3) Keep the lower jaw in good position throughout the
+   administration.
+
+   (4) Avoid turning the face from the lateral to the dorsal (face
+   up) position unless essential. If it has to be done, be careful
+   first to mop out any “pool” from the dependent cheek.
+
+   (5) Deal as effectively as possible with the earliest appearance
+   of laryngeal stridor.
+
+Let us see how in a normal case, these rules can be applied. With
+the patient lying (or, in exceptional circumstances, sitting) in a
+comfortable position, the shoulders and head raised above the rest of
+the body and the face looking upwards (or straight forwards, in the
+case of the sitting patient), the anæsthetic is begun slowly, and the
+patient encouraged to take his time and to breathe naturally. At this
+stage the jaw needs no support, the muscles being neither relaxed by
+deep anæsthesia, nor spastic from asphyxia. With the advent of muscular
+relaxation, the head is turned to one side, that which is opposite to
+the side on which the surgeon will be working, being usually chosen.
+We must now determine whether the patient can breathe best through the
+mouth or the nose, and make sure that the channel chosen is as free as
+possible. In the majority of cases it will be found that respiration is
+oral, and that all that is necessary is to support the lower jaw by a
+finger hooked into the depression just below the symphysis mentes. The
+hands of the anæsthetist, therefore, take up a position from which in
+nine cases out of ten they will never require to be moved.
+
+_The hand of the side toward which the patient’s face is turned_
+supports the jaw and keeps the face-piece or mask adapted to the face.
+The middle finger is pressed into the space below the symphysis mentis,
+and _exercises traction forwards and a little upwards_, thus preventing
+the jaw from slipping backwards; the index finger lies along the lower
+part of the mask, maintaining adaptation between it and the chin; the
+thumb bears on the mask higher up, keeping its upper part pressed
+against the bridge of the patient’s nose, and also serving as a _point
+d’appui_, or fulcrum, from which the jaw traction by the middle finger
+can conveniently be exercised. This grip once learnt is not fatiguing
+to the hand, and is in the author’s opinion one of the essential points
+for the beginner to master (_see_ Fig. 28C, page 85).
+
+_The opposite hand_ holds the drop bottle, if the method in use is
+an open one, the wrist resting upon the uppermost side of the patient’s
+head.
+
+  [Illustration: FIG. 6.--Hewitt’s dental props.]
+
+Fig. 28C shows this grip in operation, while Fig. 28D shows the
+alternative frequently adopted. This alternative has various
+disadvantages. It covers up a larger part of the patient’s face than
+the method recommended, and it tends to tilt the mask sideways. The
+little finger is supposed to be hooking forward the jaw by pressing
+behind its angle, but such a method is very fatiguing if in use for
+more than a few moments.
+
+In a proportion of cases, it is found that a free air-way cannot be
+maintained by these simple measures. Upper or lower teeth (or both)
+may be missing and traction upon the lower jaw only closes the mouth
+the more firmly. In most of these cases, the difficulty can be met
+by the use of the _dental prop_. These are made in various sizes and
+shapes, of which the best known are Hewitt’s and Bellamy Gardner’s
+(_see_ Figs. 6 and 7). The latter are made of aluminium and are of
+small size only. They are the most convenient for cases with teeth
+both in the upper and lower jaw, but who suffer from a receding lower
+jaw not easily kept forward unless the prop is used as a rocker, as it
+were, upon which it can be slid forward. Hewitt’s props are of plated
+metal, with lead on the cups, to avoid injury to the teeth. They are
+made in five sizes, of which the middle and larger are very convenient
+for cases in which one or both rows of teeth are missing.
+
+  [Illustration: FIG. 7.--Bellamy Gardner’s Dental
+  Props.]
+
+  [Illustration: FIG. 8.--Phillips’ modification of
+  Hewitt’s artificial airway.]
+
+For cases entirely without teeth, and in which a large flabby tongue
+is prone to fall back over the epiglottis, the mouth tube (Fig. 8) is
+very convenient. The rubber shank lies along the top of the tongue, the
+metal end lies between the gums. As originally introduced by Hewitt,
+the air-way was circular in cross section, but the flattened model
+figured is a distinct improvement. It was introduced by Dr Phillips.
+
+  [Illustration: FIG. 9.--Silk’s nasal tubes.]
+
+Occasionally one decides to facilitate nasal rather than oral
+breathing, and if the natural passages are inadequate, recourse may be
+had to the passage of a short piece of drainage tube of the calibre of
+a number 10 catheter, and about 3 inches in length. With such a tube
+in one or both sides of the nose, reaching from anterior to posterior
+nares, nasal respiration is usually possible even in much obstructed
+noses (Silk). (Fig. 9.)
+
+  [Illustration: FIG. 10A.--Bellamy Gardner’s
+  tongue-clip.]
+
+  [Illustration: FIG. 10B. Ring tongue
+  forceps.]
+
+  [Illustration: FIG. 10C. Glossotilt.]
+
+  [Illustration: FIG. 11A.--Boxwood wedge for
+  opening jaws.]
+
+  [Illustration: FIG. 11B.--Wedge for opening
+  jaws.]
+
+  [Illustration: FIG. 11C.--Mouth gag.]
+
+If proper and timely use be made of one or other of these simple
+devices, the use of the _tongue forceps_ is rarely necessary.
+
+Occasionally, however, it may be required, and a suitable appliance
+should always be at hand for an emergency. Fig. 10 shows two types. The
+little clip of Mr Bellamy Gardner is preferable to the ring type, the
+passage of the spike through the tongue substance producing less after
+pain, than the bruising following the use of the other instrument. The
+third drawing in Fig. 10 is of an instrument not much known outside
+Edinburgh; it is called a glossotilt, and is intended to lever forward
+the base of the tongue, as an alternative to nipping the tip of the
+organ with forceps, and has, in the opinion of some, various advantages.
+
+Before using either mouth prop or tongue forceps, it is occasionally
+necessary to use some mechanical means to lever open a tightly clenched
+jaw. The earlier one interferes in a case of mechanical asphyxia, the
+less necessity will exist for the use of such means. Fig. 11 shows two
+well-known mouth gags, and also a box-wood wedge, the use of which is
+less liable to injure teeth than a metal instrument. If a gag is used,
+the blades when closed should lie the one behind the other, not side
+by side. This ensures a minimal thickness to be inserted between the
+tightly clenched teeth.
+
+
+                    Treatment of Laryngeal Stridor.
+
+This is of necessity difficult since the causation of the condition is
+in many cases obscure. _The error_ common to most beginners, and to
+many who would resent such a title being applied to them, is to regard
+the appearance of stridor as an indication to _deepen the anæsthesia_.
+Whether the cause lie in local irritation of the laryngeal mucous
+membrane or in some stimulus from the area of operation, the condition
+is presumably always essentially a reflex spasm of the adductors of
+the vocal cords, but it is a _reflex which may persist even in an
+anæsthesia so deep that the vital medullary centres are in peril_.
+
+The preventive treatment consists chiefly in following the other rules
+set forth above for the prevention of asphyxia with such faithful care,
+that the patient never enters into the vicious circle of asphyxia of
+which stridor is so prominent a feature. Patience in the induction
+stage--the avoidance of _forcing_ the anæsthetic upon the patient--is a
+safeguard not to be forgotten.
+
+Once the condition has arisen, it saves time to _withdraw the
+anæsthetic_ altogether, and to allow the patient to breathe nothing
+but fresh air. Brisk friction of the lips with a rough towel often
+does good, presumably by setting up a “cross reflex.” In severe cases,
+a most valuable measure is the inhalation of pure oxygen, a cylinder
+of which should always be at hand in the operating theatre. Even an
+obstructed air-way will convey enough undiluted oxygen to reduce the
+venosity of the blood, and so cut across the “vicious circle.”
+
+So much for the treatment of the early stages of asphyxia, the more
+advanced stages constitute one of the “accidents of anæsthesia,” and
+are dealt with in Chapter XVI.
+
+
+
+
+                              CHAPTER IV.
+
+                       METHODS OF ANÆSTHETISING.
+
+
+Certain terms such as “open method,” “closed method,” etc., are used in
+describing different systems of anæsthetising, and it will save time
+later if these are now defined.
+
+The OPEN METHOD is one in which the drug is dropped or poured upon
+a fabric stretched on a mask which does not lie in close apposition
+to the face. If the student will experiment with such a mask as
+Schimmelbusch’s, he will find that by no effort can he make its whole
+circumference touch his face at the same time. Anæsthetics vapourised
+from such masks must of necessity be inhaled freely diluted with fresh
+air. These masks are only suitable for use with chloroform.
+
+The PERHALATION METHOD.--This term is not used often, but it is the
+most strictly correct name to give to the process commonly called
+“open ether.” If the student will examine Bellamy Gardner’s open ether
+mask (Fig. 27) he will find that it is deliberately shaped to lie
+over its entire circumference in close apposition to the face of the
+average patient. In actual use it is well however to make sure of this
+apposition by the use of a ring of gauze as shown in Fig. 28A. Upon the
+mask is stretched gauze of a thickness just as great as will permit
+free respiration to take place through its layers. The whole bulk of
+the respired air must pass _through the fabric_, none escaping between
+the face and mask.
+
+The term “SEMI-OPEN” is applied to various methods now rarely seen. One
+of the best known of these was the anæsthetic cone, still used by a few
+for C.E. mixture (_see_ Fig. 45).
+
+The term “CLOSED METHOD” is applied to one in which the patient
+breathes in and out of a closed bag. The Clover and Ormsby inhalers are
+“closed” instruments. With this method the patient rapidly uses up the
+oxygen of the contained air, and accumulates considerable CO_{2}; life
+could not be sustained for any long period of time under such a system.
+Oxygen must be supplied from time to time by permitting say one breath
+in five to be taken from the fresh air instead of from that in the bag.
+Alternatively, oxygen from a cylinder may be supplied by an accessory
+pipe into the inhaler.
+
+       *       *       *       *       *
+
+This method is also referred to as the RE-BREATHING METHOD.
+
+       *       *       *       *       *
+
+The VALVED METHOD is used only with “gas” or “gas-oxygen.” The
+facepiece fitting accurately, the patient draws all the volume of
+his inspiration from the inhaler: his expirations he propels through
+a valve, into the general atmosphere of the room. If nitrous oxide
+unmixed with oxygen is being given, the patient suffers from oxygen
+starvation even more rapidly and completely than in the re-breathing
+method. During the induction period of gas anæsthesia, such oxygen
+starvation is practised deliberately, and if not pushed too far is
+harmless. It cannot, however, be continued for more than a brief space
+of time. The admixture of oxygen to the vapour being breathed entirely
+abolishes this unfavourable feature of the valved method.
+
+There is, however, another consequence of the use of “valves” which
+is unaffected by the addition of oxygen. Reference has already been
+made to _Yandell Henderson’s acapnic theory_, and if under any form
+of anæsthesia the patient can be reduced to a condition _of CO_{2}
+starvation_, it will be when the valved system of administration is in
+operation for a prolonged period. As a matter of experience, patients
+breathing “on the valves” do often exhibit shallow respirations and
+slight pallor which is rapidly and very strikingly remedied by turning
+to the rebreathing method. One can hardly doubt that the improvement
+is due to a gradual re-accumulation of carbon di-oxide in the blood and
+tissues.
+
+Two other terms referring not to the type of inhaler but to the method
+of supplying the drug, are in use.
+
+By the “DROP” METHOD, we mean one in which the anæsthetic is supplied
+in a steady series of drops. The flow may be quick or slow, but it
+always arrives on the mask in isolated drops of uniform size. Such a
+method demands more constant attention than the next to be described,
+but it is capable of yielding that even uniformity of vapour strength
+so desirable in open methods.
+
+THE DOUCHE METHOD is unfortunately far more commonly used by those
+whose attention has never been drawn to the significance of the
+difference between the two. Supplies of the drug rendered, say, every
+twenty seconds cannot possibly give an even vapour strength.
+
+“SINGLE DOSE” methods are of use chiefly in dental surgery. The patient
+is charged up with the anæsthetic, and the operator has to begin his
+work as soon as the mask is withdrawn from the face, ceasing as soon as
+the patient shows any signs of recovering consciousness of pain.
+
+Single dose anæsthetics are in a class by themselves. In order to
+achieve success with them, special experience on the part of the
+administrator and mutual confidence between operator and anæsthetist
+are essential.
+
+The period of anæsthesia available to the operator which any particular
+“single dose” anæsthetic may be expected to yield is obviously a matter
+of the first importance, and the table given in Chapter XIX.
+will be found helpful in this connection.
+
+
+
+
+                              CHAPTER V.
+
+               THE CLINICAL OBSERVATION OF THE PATIENT.
+
+
+                         Stages of Anæsthesia.
+
+Anæsthesia has been divided into four clinical stages corresponding
+to the degrees to which the nervous system has been affected. The
+boundaries between these stages are often ill-defined, but the
+terminology has some value as facilitating description.
+
+THE FIRST STAGE lasts from the commencement of inhalation up to the
+time when volitional self-control is lost by the patient.
+
+THE SECOND STAGE in the older text-books was said to be characterised
+by struggling, shouting, and breath-holding. With a patient not
+addicted to alcohol and with the anæsthetic skilfully administered,
+this description is unduly lurid.
+
+THE THIRD STAGE is that of full surgical anæsthesia.
+
+THE FOURTH STAGE is that of over-dosage.
+
+
+                  The Ocular Reflexes in Anæsthesia.
+
+These give such valuable assistance to the anæsthetist that it will be
+well to define and describe them as a preliminary. They are three in
+number.
+
+THE CONJUNCTIVAL REFLEX is best elicited by drawing the upper lid
+upwards from the eyeball and retaining it in that position with one
+finger, while with another finger the ocular conjunctiva is lightly
+touched in the area of the inner canthus. If the anæsthesia is very
+light, both lids attempt to approximate and close the palebral
+fissure. The upper lid may slip down from under the retaining finger
+and come into its proper place, while the lower lid is elevated. At
+a deeper level of anæsthesia there is not complete action of the
+orbicularis but merely of a certain part of it, so that all that is
+observed is a _twitch inwards of the lower lid_. Even this form of the
+reflex disappears before the corneal reflex.
+
+THE CORNEAL REFLEX is elicited by pushing up the upper lid by one
+finger and with the pulp of the _same_ finger lightly brushing the
+centre of the cornea as soon as it is exposed, when we feel or see the
+upper lid come back into position with a sharp definite twitch. The
+examining finger must be slipped smartly out of the way as soon as
+the cornea has been touched. Even in deep anæsthesia, a trace of this
+reflex can usually be elicited if the little manipulation be properly
+performed.
+
+The conjunctival and corneal reflexes are frequently confused in the
+mind of the student. The most common mistake made is to pin the upper
+lid firmly somewhere in the region of the bony roof of the orbit,
+to dab the eye far too vigorously, and to believe that no reflex is
+present because no movement of the upper lid takes place. In the first
+place, the upper lid cannot move if it is rigidly held against a bony
+plate: in the second place, it is wholly unnecessary to inflict upon
+the cornea more than the lightest of touches. Both these reflexes
+are to be used with great discretion, undue frequency and excessive
+vigour of touch being alike capable of setting up serious inflammatory
+reaction.
+
+THE PUPILLARY LIGHT REFLEX is elicited by shutting off light from
+_both_ pupils for ten to twenty seconds and then smartly withdrawing
+the protecting fingers and allowing as strong a light as possible to
+fall on to the eye. The response of the ciliary muscle should _always_
+be present; its absence is a certain indication of something wrong:
+some sluggishness may be permissible under ether, but even that is
+suggestive of trouble if chloroform is the anæsthetic.
+
+The use of a preliminary hypodermic of morphia tends to make the pupil
+somewhat smaller than normal, and to elicit the light reflex it may be
+necessary to cut off illumination for a somewhat longer period than
+if no morphia had been given. Nevertheless with a little care, the
+light reflex should always be capable of demonstration even in the
+morphinised subject.
+
+
+                   The Observation of a Normal Case.
+
+In the case of nitrous oxide and of ethyl chloride, the patient passes
+through the various stages very rapidly, and the picture of anæsthesia
+as induced by either of these two is therefore best described
+separately. The following may be taken, therefore, as an account of
+what is to be observed in the patient inhaling ether or chloroform,
+unless a specific reference is made to one of the other anæsthetics.
+
+FIRST STAGE.--The first sign that some effect is being produced in the
+patient is usually the appearance of the movements of _swallowing_;
+the hyoid and thyroid can be felt or seen to be moving in conjunction
+with the muscles of deglutition. During this stage, the patient being
+still to some extent under volitional control, there should be no other
+movement noticed. The eyes are usually closed and the colour normal;
+the respiration may be hurried by excitement, but judicious handling of
+the patient will do much to minimise this.
+
+THE SECOND STAGE is really entered when volitional control is lost.
+It may be characterised by struggling and shouting by the patient,
+even if the anæsthetic is properly administered; but with a healthy
+patient and a good anæsthetist, all that usually occurs in the way of
+movement by the patient is some rigidity of the limbs and a slight
+attempt, perhaps, to lift the head from the pillow or a limb from the
+couch. The breathing tends during the first part of this stage to be
+light and is rarely entirely regular: slight pauses occur, usually
+after an inspiration, less commonly after expiration. Serious “holding
+of the breath” (after an inspiration) rarely occurs save in the type
+of patient who is also struggling; if it does occur to a degree which
+causes any blueness of the patient’s face (cyanosis), it usually calls
+for the removal of the anæsthetic for a moment until normal breathing
+has been resumed.
+
+The colour of the face rarely departs much from normal during the
+second stage, unless cyanosis from breath-holding intervenes.
+
+The eyes are usually opened, as the second stage progresses, and the
+eyeballs tend to rotate slowly in every plane. The pupils are usually
+large, but react sharply to light. Both conjunctival and corneal
+reflexes are brisk.
+
+THE ONSET OF THE THIRD STAGE is marked by the appearance of muscular
+relaxation. Any limb which the patient may have been holding rigidly
+up sinks down on to the couch, and it will be found that if an attempt
+be now made by the anæsthetist (as it should be) to turn the head of
+the patient to one side or another, the muscles of the neck no longer
+resist.
+
+_The respiration_ also alters in type, losing its tendency to lightness
+and irregularity, and becomes full, deep, and regular. In open ether
+anæsthesia particularly, expiration commonly assumes a “blowing” type
+very characteristic, and which to the trained ear is of itself an
+indication that full surgical anæsthesia is present or at any rate not
+far distant.
+
+_The colour_ varies somewhat with the anæsthetic in use. With ether it
+is usually somewhat higher than normal, and a trace of blueness may
+be present if the method is the “closed” one. Anything more than a
+trace, however, must be regarded as abnormal, whatever the method or
+anæsthetic may be. With chloroform the colour is perhaps a little paler
+than that normal to the individual.
+
+_The eyelids_ are usually half open, and the eyeballs at rest looking
+forward and slightly downwards. An extreme rotation downward may
+usually be taken as a sign of very deep anæsthesia. _The pupil_ is, as
+already said, always active to light, but its actual size varies with
+the anæsthetic used. With ether, particularly “closed” ether, it may be
+large (4–5 millimetres): with open ether, preceded by morphia, about
+3–4 millimetres: a good chloroform anæsthesia usually exhibits a pupil
+of only 2–3 millimetres, and if morphia has also been given, it may be
+pin-point in size. Too much emphasis must not be placed, however, upon
+the mere size of the pupil; that may vary within wide limits without
+necessarily indicating serious abnormality. The essential point is that
+the light reflex shall be brisk. A pupil of 5 millimetres reacting
+sharply to light may be of no special moment: one of that size immobile
+to light would cause real anxiety.
+
+_The conjunctival reflex_ usually disappears fairly early in the
+third stage: if briskly present, the anæsthesia is certainly a light
+one, and probably insufficient for an abdominal section. _The corneal
+reflex_ if properly taken in the way already described can usually
+be elicited throughout the third stage. In an anæsthesia deep enough
+for abdominal section it is, of course, not brisk, but we may say
+generally that its entire absence is _presumptive_ evidence of a very
+deep anæsthesia--probably undesirably deep. It must not be forgotten
+that some local causes such as drying of the surface of the cornea
+may cause it to disappear, and in case of doubt it is sometimes worth
+while to wash out the eye with a little saline solution. If after doing
+so the anæsthetist still finds the reflex not present he should be on
+his guard. Provided, however, that the light reflex is still present
+and colour and respiration satisfactory, he need not consider that the
+patient is in any immediate danger.
+
+Broadly speaking, then, the third stage, the stage which is called for
+by the requirements of major surgery, is characterised by (1) full
+regular respirations; (2) colour not much removed from normal; (3)
+moderate sized pupil, larger in the case of ether than chloroform; (4)
+conjunctival reflex faint or absent; (5) corneal reflex just present,
+or, in a deep third stage, just absent; (6) light reflex present: these
+may be regarded _as the signs of fully developed surgical anæsthesia_.
+
+The absolute beginner may be so completely out of his reckoning as
+to mistake the quietude of the later part of the first stage for the
+appearance of the third stage. For the prevention of so gross an error
+as that, the reader need only be referred to a patient study of the
+foregoing. But even a man with considerable experience may frequently
+be in doubt exactly as to _how far through the third stage his patient
+has passed_. He may have attained a level which will permit an incision
+to be made into the skin without movement on the part of the patient,
+but not one which would relax the abdominal muscles sufficiently for
+the peritoneum to be opened without eliciting considerable resistance
+from the abdominal muscles. In such moments of doubt, the author is
+accustomed to request the surgeon to make his skin incision, and
+_observe the effect which this trauma has upon the depth, frequency,
+and regularity of respiration_. This furnishes a most valuable guide
+to the depth of anæsthesia. In a third stage of very light degree, the
+respiratory rhythm will be interrupted and the breath held for a second
+in inspiration. Apart from any other sign, that may be taken as an
+index that the anæsthesia is very light--too light to permit of opening
+the peritoneal cavity. In a very deep anæsthesia the respiration
+is little affected by the skin incision, while at a moderate and
+more desirable level the respiration is quickened and deepened, but
+unaffected in the regularity of its rhythm.
+
+THE FOURTH STAGE IS STAGE OF OVER-DOSE.--This stage is, of course,
+never entered voluntarily. Its earliest signs are loss of all tone in
+the muscles of expression, complete loss of corneal reflex, a widely
+dilated pupil _insensitive to light_, and a type of respiration which
+though definitely weakened may show occasional deep gasps. Circulatory
+failure and cessation of respiration from failure of the medullary
+centre are the closing phenomena of overdose.
+
+
+                    The Circulation in Anæsthesia.
+
+It will be perhaps noticed that in the foregoing, no reference has
+been made to the examination of the pulse. This is not an oversight on
+the part of the author. It is perfectly true that under any anæsthetic
+not complicated by an asphysical element, the blood pressure falls as
+the drug takes effect, and that in the case of chloroform the fall is
+often quite considerable. Such a fall can be appreciated by the skilled
+finger, but only by concentrating upon that examination a degree of
+attention which necessarily detracts from the administrator’s available
+energy for the observation of other signs which are of equal value, and
+can be more rapidly and certainly appreciated and appraised.
+
+It is nevertheless essential to assure oneself during the whole
+progress of an anæsthesia that the circulation is in a satisfactory
+condition. Two obvious guides to this are the colour of the patient’s
+face and the force with which cut arteries spout. As regards the colour
+in circulatory failure, one would naturally expect a pallid face, and
+this indeed is the rule. It must not be forgotten, however, _that
+cyanosis may sometimes be cardiac in origin_. Cases do sometimes occur
+when a bluish tinge is seen on the lips, ears, and nostrils, apart from
+any obvious cause of oxygen starvation. In these we may reasonably
+suspect that the right heart is failing, and take measures accordingly.
+
+Another valuable index to the state of the circulation is the “skin
+reflex,” that is, the speed with which the circulation returns to an
+area of the skin which has been pinched. The student should train his
+eye by occasionally pinching the lobule of the patient’s ear and
+observing first the white area so produced, and later the rate at
+which, in a normal case, the healthy colour returns.
+
+
+                   Abnormal Phenomena in Anæsthesia.
+
+It is not intended to furnish here any account of matters more suitably
+treated under the “Accidents of Anæsthesia,” which are fully described
+in Chapter xvi., but merely to draw the attention of the student to
+certain departures from the normal course of anæsthesia which are
+encountered with varying frequency, to ascribe them as far as possible
+to their true causation, and indicate methods of prevention.
+
+The abnormalities fall into two classes, those connected with the
+nervous and muscular systems, and those in which respiratory changes
+are evident.
+
+
+                       MOTOR AND NERVOUS SYSTEM.
+
+_Clonus or tremor_ sometimes appears in one or more limbs, even the
+trunk being affected in severe cases. Ether is practically the only
+anæsthetic under which the tremor ever appears, and the condition is
+often spoken of as “ether tremor.” It rarely appears in the female
+subject, being almost limited to powerfully built young men. Coming
+on towards the end of the second stage, it frequently persists in the
+deepest of third stages, and in bad cases there is usually no option
+but to change over to chloroform--always supposing that the tremor will
+interfere with the work of the surgeon. If it will not, the condition
+calls for no active treatment, since it is in itself not dangerous.
+
+_Movements recalling to the observer the condition of athetosis seen
+in the limbs of hemiplegics_ are occasionally seen in the anæsthetised
+patient. The fingers of a hand may be slowly moved, or one or other
+shoulder may be shrugged. The exact cause of these movements is
+obscure. They occur in all types, both sexes, and at all ages; they are
+not necessarily asphyxia though a trace of asphyxia seems sometimes
+to conduce to them. They persist for some time after the third stage
+has been entered, and ultimately disappear without any obvious cause
+other than the passage of time. It is rare for them to continue more
+than five or ten minutes after full anæsthesia has been induced. Their
+practical importance lies purely in this, that the inexperienced
+anæsthetist observing some muscular movements still persisting, may
+take them as an infallible sign that anæsthesia is not complete, and
+may deliberately take his patient to a deeper level. If in doubt, the
+anæsthetist must, of course, consult all the other recognised guides,
+such as the eye reflexes, but once he has seen these movements in a
+case, and had demonstrated to him _their slow, rhythmical character_,
+he is not likely to be misled on a future occasion.
+
+_Muscular rigidity_ has been mentioned already in Chapter iii. When
+it persists in a patient in whom other signs suggest that a full
+anæsthesia has been produced, the anæsthetist will usually find that
+attention to the air-way, and perhaps a whiff of oxygen, will remedy
+the trouble.
+
+
+                      Respiratory Abnormalities.
+
+_Shallow breathing_ or even slight temporary arrests of
+respiration arise frequently. During the induction stage they may be
+due to:--
+
+   1. Apnœa or acapnia following voluntary excessive breathing.
+
+   2. Using morphia before chloroform.
+
+At a later stage, it may be due to:--
+
+   1. Acapnia following excessive breathing excited reflexly from
+   the seat of operation.
+
+   2. Direct reflex inhibition of the respiratory centre.
+   An example of this is seen sometimes when the bladder is
+   over-distended by lotion.
+
+   3. Impending vomiting.
+
+_Moist sounds_ not uncommonly appear. The student’s general knowledge
+of medicine will enable him to decide whether the fluid is likely to
+be in the pharynx, larynx, trachea, or bronchi. If in one of the first
+two named, it will suffice to swab out the throat and encourage the
+patient to cough. If, however, moisture is evidently present in the
+trachea or bronchi, the condition is one calling for considerable care
+and judgment. It arises more commonly with ether than with chloroform.
+Much will depend upon how much longer the surgeon requires to finish
+his operation. If only a few minutes more are required, nothing is
+necessary but to cut down the amount of ether being given to the
+minimum possible. If, however, the surgeon has still a good deal to do,
+the safest thing is to withdraw the ether and substitute chloroform
+or a mixture. Be it clearly understood, however, that such a change
+over is not devoid of risk. If it is to be made, it must be done
+early, before the patient is cyanosed and almost drowned in his own
+secretion. In a neglected case where cyanosis has already appeared,
+there will be no option but to interrupt the operation, empty the chest
+by encouraging coughing, and to aid the process by compressing the
+patient’s chest during expiration. Thereafter chloroform may be given,
+but with the greatest care.
+
+_Gasping and sighing_ are not common phenomena but when they occur,
+call for close notice from the anæsthetist. Excluding, of course, such
+occurrences in the first stage, before volitional control has been
+lost, they may be _usually but not invariably ascribed to overdosage
+or to the appearance of definite surgical shock_. Whenever they are
+noticed, therefore, it behoves the administrator to overhaul the
+patient thoroughly, to consult the eye reflexes, the skin reflex, and
+the pulse, and not to rest until he is assured that there are no other
+signals of danger to be found.
+
+_Stertor and stridor._ The first of these is caused by flapping of the
+soft palate. It is a noise low in pitch, resembling ordinary snoring.
+Indicating as it does that the palatal and therefore probably other
+muscles, are relaxed, it may if moderate in volume usually be taken as
+a favourable sign. If it becomes very loud, however, the probability
+is that the base of the tongue has fallen back; cyanosis will begin to
+appear, but will immediately be remedied by pulling forward the jaw or
+in extreme cases, using the tongue forceps.
+
+_Stridor_ is a high-pitched sound produced by approximation of the
+vocal cords. It has already been dealt with in Chapter iii.
+
+
+                           False Anæsthesia.
+
+This term has been applied to a condition often seen in children,
+and occasionally in adults. It is almost limited to chloroform: the
+author has never seen a genuine case when ether has been in use. It
+appears very quickly after inhalation has begun: the muscles are
+relaxed, the respirations quiet and regular, the conjunctival reflex
+sluggish. A very marked feature is the excessive smallness of the
+pupil. Obviously then, the condition much resembles a true third stage,
+but if the operation be begun, the mistake will very rapidly be made
+evident, for the patient will at once move and cry out. In essence, the
+condition is simply one of ordinary sleep. It can be recognised by its
+appearance after a period of inhalation too brief for the induction
+of true anæsthesia, by the very small pupils and the lightness of the
+respiration. It will be a waste of time to permit the condition to
+continue, as the lightness of the respiration delays the taking in of
+a dose of the anæsthetic sufficient to induce a proper third stage.
+The remedy is simple,--rub the lips and face smartly with a towel or
+the hand, when respiration will at once deepen and the pupil dilate.
+Thereafter, the induction should proceed normally.
+
+
+
+
+                              CHAPTER VI.
+
+                      PREPARATION OF THE PATIENT.
+
+
+For all but short anæsthesias conducted chiefly by nitrous oxide, the
+intestinal tract of the patient must receive careful preparation. In
+doing this, one must avoid excessive starvation and purgation, both of
+which tend to increase shock.
+
+We will suppose that the operation is timed for 10 a.m. on Tuesday
+morning. On Monday morning the patient receives an aperient which
+may be varied a little to suit his taste and habits. If he has no
+preference, there is nothing better than an ounce of castor oil. During
+the rest of Monday, he has a light diet: fish and milk pudding in the
+middle of the day, a little soup at night. The aperient should operate
+before 9 p.m. When that is over, the patient retires to bed. During the
+day he may be allowed to move about his room a little, but should not
+undertake any exertion.
+
+If there be excessive nervousness, or a natural tendency to insomnia,
+sulphonal gr. 15 or veronal gr. 8 may be given early in the evening, to
+ensure a night’s rest.
+
+About 6 a.m. on Tuesday morning, a large soap and water enema is given,
+and when this has operated, a cup of tea or a little soup or Bovril may
+be taken. Thereafter nothing should be given by mouth.
+
+The early forenoon is the time of choice for any operation, but if
+an afternoon time be of necessity chosen, the patient should not be
+starved throughout the forenoon. A repetition of the early morning meal
+may be allowed about 11 a.m.
+
+In cases such as gastro-enterostomy, where the alimentary tract will be
+opened, the preparation must be a little more stringent. It is usual
+to allow no solids at all the day before. A saline enema may be given
+an hour or two before operation, when the soap and water has been
+evacuated.
+
+
+                  Preliminary Hypodermic Medication.
+
+This great improvement in anæsthesia was practised many years ago by
+a few surgeons, but it was only when open ether assumed its present
+position of pre-eminence that it was widely adopted.
+
+The present routine is to give morphia gr. ⅙, atropine gr. ¹⁄₁₂₀ to
+adult patients three quarters of an hour before operation. It has the
+following _advantages_:--
+
+   (1) The nervous fears of the patient give place to a feeling of
+   bien-être.
+
+   (2) The secretions of saliva and of mucous from the respiratory
+   mucous membranes are limited.
+
+   (3) A little less inhalational anæsthetic is required.
+
+   (4) The after vomiting is lessened, and probably the liability
+   to inflammatory respiratory complications also reduced.
+
+The _disadvantages_ can be met by proper care and dosage. They are as
+follows:--
+
+   (1) Morphia _plus_ chloroform depresses the respiratory centre
+   at an early stage of anæsthesia. Respiration becomes infrequent
+   and shallow, and cyanosis appears before the patient is really
+   sufficiently anæsthetised for the purposes of the surgeon.
+
+   (2) The larger the dose of morphia, the more troublesome is this
+   premature failure of respiration.
+
+_The moral_ is obvious: give the small doses above recommended and
+induced with mixtures weak in chloroform, or better still with ether
+only (see page 86).
+
+Some years ago, before these facts were appreciated, there was a
+fashion for giving very large doses of preliminary narcotics. The
+combinations most favoured were as follows:--
+
+
+                         SCOPOLAMINE-MORPHINE.
+
+Scopolamine is a form of hyoscyamine and is itself a powerful narcotic.
+Two or sometimes three doses of the mixed drugs were given at intervals
+of an hour, the last half an hour before operation. Scopolamine gr.
+¹⁄₂₀₀, morphia gr. ⅛ was the usual formula: some surgeons added a dose
+of atropine or strychnine with the idea of stimulating the respiratory
+centre.
+
+The patients went to the operating or anæsthetising room so drowsy
+that they were unaware of their surroundings, and afterwards had no
+recollection of the actual beginning of the inhalation. So humane a
+method naturally attracted a good deal of attention, but the serious
+depression of the respiratory centre which seems inevitable in the
+method has gradually caused it to disappear from the practice of
+most surgeons and anæsthetists. At the present day, it is only to
+be recommended in midwifery practice; to the drowsy semi-conscious
+condition produced, the name of _Twilight Sleep_ has been given.
+
+
+                   OMNOPON AND OMNOPON-SCOPOLAMINE.
+
+Omnopon is composed of a mixture of several of the alkaloids derived
+from opium; the makers claim that it produces less after malaise than
+morphia alone. It may be given before anæsthesia in doses of ⅙–⅓ gr.,
+either alone or combine with a small dose of scopolamine. It gives
+quite good results if not pushed to excess.
+
+
+                         HEROIN HYDROCHLORIDE
+
+This comparatively modern sedative is used by some surgeons in
+preference to morphia. A dose of ¹⁄₁₂ gr. is quite sufficient, three
+quarters of an hour before operation. Atropine should always be
+combined with it.
+
+       *       *       *       *       *
+
+To young children, morphia should not be given, but atropine may be
+given freely. A child of twelve months tolerates a dose of ¹⁄₂₀₀ gr.
+quite well: one of six years, will take ¹⁄₁₅₀ gr.
+
+In ages ranging from 12 years upwards, greatly reduced doses of morphia
+may be given. No child under 15 years requires more than ¹⁄₁₂ gr. of
+morphia at most.
+
+
+
+
+                             CHAPTER VII.
+
+                            NITROUS OXIDE.
+
+
+                          Special Physiology.
+
+Upon the nervous system, nitrous oxide acts like other anæsthetics,
+but the stages of anæsthesia are passed through so rapidly that a
+second stage can hardly be distinguished. It is rare for struggling or
+excitement to be manifest, unless air or oxygen be admitted at the same
+time, when the effect which led Humphrey Davy more than a century ago
+to apply to nitrous oxide the name of “laughing gas” is very evident
+indeed.
+
+Upon the other systems of the body, nitrous oxide has little if any
+effect in itself. The essential point to remember in connection with
+nitrous oxide administered unmixed with air or oxygen is that there
+is an _inevitable element of asphyxia_. The larger part of the
+oxygen normally carried by the red blood corpuscles is eliminated
+and replaced by N_{2}O: oxygen starvation is therefore of necessity
+present. In other words, the “vicious circle of asphyxia” (_see_
+Fig. 5) is entered, and muscular spasm is bound ultimately to appear.
+Moreover, the blood pressure rises very materially as a result of the
+lack of oxygen. That no harm results to the normal healthy patient
+from this rise is due to the fact that the gas does not in itself
+poison the heart muscle, which can therefore stand up to the extra
+strain of working against higher resistance, so long as the process
+is not carried to extremes. A heart muscle weakened by the action of
+chloroform would give out at once if exposed to such a test.
+
+
+                              Apparatus.
+
+Nitrous oxide is supplied by the makers as a fluid condensed in iron
+bottles or cylinders, and only becomes gaseous upon being released from
+them. In passing from the fluid to the gaseous state, heat is of course
+lost, and it will be noticed that the end of the cylinder which is in
+use becomes rapidly crusted over with frost. Ice, moreover, forms in
+the small channel at the head of a cylinder, and is apt from time to
+time to block it.
+
+The cylinders are of various sizes and designated after the numbers
+of gallons of gas which they will supply: 25 is the smallest size, 50
+or 100 are more usual; anything up to 500 is occasionally met with in
+hospital practice. Moreover the cylinders are of two types, called
+respectively _vertical_ (for use in the upright position), and
+_angle_ for use in the horizontal position (_see_ Fig. 13).
+
+  [Illustration: FIG. 12.--Frame for adapting vertical
+  cylinders to foot use.]
+
+  [Illustration:
+
+    FIG. 13A.       FIG. 13B.
+
+  Two types of N_{2}O cylinders.
+
+    A. Vertical (or ordinary).       B. Angle.]
+
+The cylinders are fixed in frames of various types of which examples
+are seen in Figs. 13 and 14.
+
+Upon each cylinder, of whatever size or type, will be found a label
+stating its weight when full and empty, the difference representing
+the weight of the contents when the bottle is full. For instance, in
+the case of the 50-gallon cylinder the weight of its full charge is 15
+ounces. Weighing the cylinder is the only certain means which we have
+to estimate how much of the charge remains. The student will readily
+appreciate therefore that once a cylinder has been used at all there
+is always a risk of the supply of gas from it running out during an
+administration. It is for this reason that cylinders are habitually
+used in couples, one of which is always supposed to be quite full. To
+this one it is well to attach a label marked “full,” and care must be
+taken to replace at once a cylinder known to be empty. In this way we
+always have upon the frame one cylinder partly and another entirely
+full.
+
+  [Illustration: FIG. 14.--Complete N_{2}O apparatus,
+  showing twin cylinders, supply pipe, 2-gallon bag, 3-way tap,
+  and face-piece.]
+
+By whatever makers the cylinder is supplied it will be found that the
+thread upon the outlet pipe is the same, and the metal nipple figured
+in Fig. 14 will fit it. To the distal end of the nipple, a rubber tube
+is attached which leads to a rubber bag usually of 2 gallons capacity.
+
+The remainder of the apparatus may be of several types.
+
+Fig. 15 shows the ordinary _Barth three-way_ tap with facepiece;
+the indicator on the tap has three possible positions designated on
+the dial as “Air,” “Valves,” and “No Valves.” If the tap is pointed
+backwards towards the bag at the position marked “air” the end of the
+bag is closed and the patient is breathing air only. With the tap in
+the middle position of “valves,” the inspiration of the patient will
+draw gas from the bag, but the expiration closes the valve which is now
+in operation at the orifice of the bag, and will open the expiratory
+valve which conducts the expired air into the general atmosphere. In
+the third position of “no valves” the patient breathes both in and out
+of the bag.
+
+  [Illustration: FIG. 15.--Barth 3-way N_{2}O tap.]
+
+  [Illustration: FIG. 16.--Hewitt’s wide-bore gas
+  valves.]
+
+Fig. 16 shows the Hewitt type of inhaler. The calibre of the orifices
+through which respiration takes place is greater than in the Barth
+three-way tap, and to that extent this type of valve is to be
+preferred. Although differently arranged exactly the same possibilities
+are present in it.
+
+The _facepiece_ is sometimes made of celluloid with an inflatable
+rubber edging. The object of this type of facepiece is that the
+colour of the lips may be appreciated by the anæsthetist during the
+administration. The preferable plan is to make the whole facepiece of
+rubber with an inflatable border. Such a facepiece made by a good maker
+will last many years, and is much more stable and reliable than its
+celluloid competitor.
+
+
+               The Care of the Nitrous Oxide Apparatus.
+
+This is a matter of considerable moment, particularly to those who do
+not use their apparatus every day. After use, the valves, facepiece,
+and bag should be disconnected from each other, all moisture wiped away
+from the bright parts, and the bag hung up with its open end downwards,
+and preferably in a warm room. If re-breathing has been extensively
+practiced it is well to wash the bag out with some carbolic lotion
+before hanging it up. The rubber valves in the valvepiece are liable
+to lose their elasticity, particularly if kept in a cold place after
+becoming damp. From time to time the valve piece should be taken to
+pieces, the valves carefully dried in front of a warm fire and powdered
+over with a little talc.
+
+
+                            Administration.
+
+Most commonly nitrous oxide is administered to a patient sitting in a
+chair. Care should be taken that the respiration of the patient shall
+not be obstructed by tight clothing round the throat or chest, and
+that the head and neck are neither unduly flexed nor extended upon the
+shoulders. The patient should not have any solid food for two hours
+before the anæsthetic. At the last moment he should be instructed to
+empty his bladder. Artificial dentures if present should be removed,
+and, if the anæsthetic is being given for the purpose of the extraction
+of a tooth, it will be necessary before applying the facepiece to
+insert between the teeth a dental prop. (See Fig. 6.) Standing to the
+left and slightly behind the patient the anæsthetist’s first step is to
+secure good apposition between facepiece and face. This is best done by
+working from above downwards: that is to say, secure first a good fit
+at the bridge of the nose, and then approximate the remainder of the
+rim of the facepiece to the cheeks and lower jaw. During this stage the
+indicator of the tap is kept at “Air.”
+
+Working with the left foot the administrator now opens the head of one
+of the cylinders with the foot key. It is wise first to have loosened
+this with a hand key, and leave it just “on the swing,” otherwise
+one’s boots are apt to suffer! Gas is allowed to flow into the bag
+until it is partially, but by no means tightly distended. The patient
+is instructed to breathe naturally and easily, and during the whole
+process the anæsthetist should converse with him in a quiet easy way.
+The tap is now turned to “valves” and the patient begins to inspire
+the gas, a supply of which is allowed to flow steadily from cylinder
+into bag. After a few breaths of the gas, when the sensibilities
+of the patient are a little dulled, it is wise to allow the gas to
+flow a little more freely and to distend the bag. This exercises
+upon the patient a slight _positive pressure_, which has been proved
+both experimentally and practically to increase the rapidity of the
+absorption.[1] The valves are left in operation for some thirty or
+forty seconds, after which time the supply of gas should be cut off
+and the tap be pushed over to the position of “no valves” for further
+twenty seconds. This should be ample to secure full gas anæsthesia.
+
+_The phenomena_ seen in nitrous oxide anæsthesia are so different from
+those of any other that a few words must be said about them. Within a
+few seconds of the inhalation beginning, the colour of the patient
+shows evidence of the presence of the gas in his blood. The normal
+complexion changes first to a dull pink, and very rapidly to the
+definite blue of cyanosis. The _eye symptoms_ are of the utmost value.
+Very early the pupil begins to dilate, and the eyeball tends during the
+first twenty or thirty seconds to rotate as if the patient were looking
+for some object in his field of vision. In full anæsthesia the eyeball,
+however, comes to rest, usually pointed downwards. The pupil is widely
+dilated, the conjunctival reflex is almost or even entirely abolished,
+but the corneal reflex is still brisk. _The respiration_ tends to
+become steadily deeper and more frequent, and in the later stages
+stertor at least, if not stridor usually develops. _The muscles_ under
+ordinary nitrous oxide anæsthesia are rarely entirely relaxed, but the
+limbs hang motionless, and it is only if an attempt be made to move
+them into some abnormal position, that one appreciates the persistence
+of muscular tone.
+
+A phenomenon peculiar to nitrous oxide anæsthesia is observed in its
+deepest stage. Designated as _jactitation_, it consists in a tremor
+beginning in the limbs, but spreading from them to the trunk if its
+development is allowed to proceed. It is a finer movement than that
+described under “ether tremor” (page 38), and wholly different in type
+from the athetosis referred to on page 38. Jactitation is almost wholly
+an asphyxial phenomenon, and is therefore definitely an indication
+that the process of oxygen starvation has been carried as far as is
+permissible.
+
+_The signs of fully developed nitrous oxide anæsthesia_ then are:--
+
+   1. Deep regular snoring respirations.
+
+   2. Dilated pupils.
+
+   3. Rotation of the eyeball downwards.
+
+   4. Loss of conjunctival but persistence of corneal reflex.
+
+   5. A colour of the skin definitely blue, but not blackish blue.
+
+   6. The commencement of jactitations.
+
+_The signs of overdose_ are:--
+
+   1. An enormously dilated pupil not re-acting to light.
+
+   2. Loss of corneal reflex.
+
+   3. A blackish blue colour.
+
+   4. Jactitations fully developed.
+
+   5. Failing respirations.
+
+The final arrest of respiration in nitrous oxide anæsthesia is usually
+painfully sudden. Upon the respiratory side the only warning is one or
+two gasps, and even that is sometimes absent. The paralysed pupil and
+the jactitations are the most useful signs of overdose.
+
+The above, then, may be taken as an account of what one expects to see
+in a normal gas anæsthesia during the induction stage. For the great
+majority of cases, nitrous oxide is given for the purpose of rendering
+painless the extraction of a tooth, and it is, in this large class of
+case, the induction stage only which need be considered. It requires
+only some fifty to sixty seconds to bring the patient to the stage
+described under the heading “fully developed anæsthesia” and when that
+has been attained, the mask may be removed and the operation begun.
+From the moment of removal of the mask, however, it must be noted that
+the patient begins to breathe fresh air and to eliminate the N_{2}O.
+The period of anæsthesia available to the surgeon or dentist during
+which he must perform the operation, is therefore very small. In thirty
+seconds the patient has frequently recovered sufficiently to begin
+to feel pain, and it is rare to secure more than forty-five or fifty
+seconds by the use of a single dose of nitrous oxide.
+
+
+                        Nitrous Oxide and Air.
+
+If the nature of the operation does not necessitate the removal of the
+mask from the face, it is possible to maintain nitrous oxide anæsthesia
+for some considerable time. The exact length of that time varies a good
+deal with two factors--the type of patient and the experience of the
+administrator. Heavily built muscular patients are not easily dealt
+with by prolonged gas anæsthesia (unless with admixture of oxygen as
+explained in chapter viii.) Of far greater importance, however, is the
+other factor. The student can easily be taught to give a single dose
+of gas for the extraction of a tooth, or the momentary incision of an
+abscess. He will, however, be wise to secure a good deal of practice in
+that class of work before attempting to prolong gas anæsthesia for more
+than a minute or two.
+
+With reasonable skill and experience and the utmost care, it is,
+however, perfectly possible to prolong nitrous oxide anæsthesia for
+periods of five, ten, or even fifteen minutes in the average healthy
+patient. As soon as the signs of full anæsthesia appear, the valve
+tap is pushed back to “air” for the space of one inspiration and
+one expiration, and then at once pushed back to “no valves.” By
+this manœuvre, one inspiration of air is permitted to the patient,
+whose colour at once shows amelioration, or at any rate no further
+progression of cyanosis. The admission of air is repeated every third,
+fourth, or at most fifth respiration. After the first minute or so
+of this cycle of events, it is obvious that the contents of the bag
+will be composed of a mixture of nitrous oxide, air, and CO_{2} in
+proportions quite impossible to calculate. It is therefore best to
+push the indicator to “valves,” and allow the bag to be emptied by the
+suction of the patient’s inspirations. The cylinder head is then opened
+by the turning of the foot-key, and the bag filled again with gas. The
+cycle of “air” and “no valves” is then begun again for another minute
+or so.
+
+It must be understood that by this process, it is not to be expected
+that an ideal anæsthesia can be produced. Some movement of the patient
+will not improbably take place when sensitive structures are cut or
+handled by the surgeon, and at no time will the muscles be entirely
+relaxed. Such an anæsthesia is therefore only suitable for a limited
+class of case, but does admirably for, say, opening an abscess,
+exploring its interior, and removing from it a sequestrum or an easily
+found foreign body. During his service in Macedonia the author had not
+at his disposal any of the appliances later to be described under the
+heading of nitrous oxide and oxygen, and found “gas and air” a most
+useful form of anæsthesia for the requirements of military surgery as
+seen in a Base Hospital, under active service conditions.
+
+
+       Contra-indications to the Use of Pure Nitrous Oxide Gas.
+
+In the healthy subject, there is no safer anæsthetic than nitrous oxide
+when administered properly and limited to its proper province.
+
+From the account given of the physiological action of the gas it will,
+however, be obvious to the student that in a limited class of case its
+use is not permissible. Such cases fall into two categories.
+
+_Firstly, cases in which an asphyxial element already exists will
+have their condition greatly aggravated by the substitution of N_{2}O
+for the oxygen in their blood._--Already caught in the vicious circle
+of asphyxia, nitrous oxide would but push them deeper into the
+vortex. Examples of such cases are patients suffering from tumours or
+inflammatory swellings in the neck which are pressing upon the air
+passages. In passing, one may note that it might be the desire of the
+surgeon to submit an individual case falling into this group to the
+operation of tracheotomy for the immediate relief of the condition. The
+short space of time required for this little operation might well tempt
+the unwary to choose nitrous oxide as the anæsthetic, and in point of
+fact such an error of judgment has more than once been made with fatal
+results.
+
+_Secondly, no patient suffering from any condition which will be
+aggravated by a sudden rise of blood pressure, should be submitted to
+nitrous oxide undiluted by oxygen._--Examples of such conditions are
+cases of _dilated right heart_ with weakened cardiac musculature.
+
+Such hearts could not be expected to work against a peripheral
+resistance suddenly raised, say, from 120 mm. of Hg, to 180 or even
+200 mm.--figures well within the possible in deep gas anæsthesia.
+Similarly, so great an increase of pressure would be dangerous
+to a patient suffering from an _aneurysm_, or from _extensive
+arterio-scelorosis_ with high blood pressure.
+
+It will be noted that the above warnings are limited to the use of pure
+nitrous oxide, that is, N_{2}O unmixed with oxygen. The extent to which
+the dangers referred to can be met by the admixture of oxygen in the
+manner to be described in the next chapter is largely a matter of the
+skill and experience of the administrator.
+
+
+                            Nasal Methods.
+
+The object of using this route is to be able to continue the
+administration throughout the period in which the dentist is doing his
+work. The essentials of a suitable apparatus are:--
+
+   1. A malleable nosepiece which can be closely adapted to the
+   nose.
+
+   2. Two supply pipes from bag to nosepiece.
+
+   3. Some means of admitting air to the stream of gas.
+
+   4. A two-gallon bag.
+
+   5. A supply of gas.
+
+   6. A mouth cover with an expiratory valve only.
+
+The patient is instructed to breathe in through the nose, but to
+expire through the mouth. The gas is supplied under some pressure and
+the mouth cover ensures that no air is inspired by that route. Some
+patients find it easier to conduct both inspiration and expiration
+through the nose, and for their benefit an expiratory valve is also
+provided in the nosepiece. After unconsciousness has supervened, nearly
+all patients begin to-and-fro nasal breathing. The mouth cover may then
+be removed, and if it be desired to economise gas, the expiratory valve
+in the nosepiece may be thrown out of action.
+
+  [Illustration: FIG. 17.--Ash’s Modification of
+  Paterson’s Nasal Gas
+
+  DESCRIPTION:--A--Nose-Cap Attachment with Stopcock for
+  Air and Gas, and with Inspiratory and Expiratory Valves
+  and Shutter. B--Nose-Cap. C--Sliding Clip on India-rubber
+  Tubings. D--Bifurcated Mount. E--Bag Mount. F--Gas Bag
+  Compressor. G--Gas Bag. H--India-rubber Tubing. MC--Mouth
+  Cover. This is fitted with an expiratory valve, and should
+  be used at the same time as the Nose-Cap. By using the two
+  together patients are more quickly anæsthetised than they
+  would be if only the Nose-Cap were used, and the Nitrous
+  Oxide is economised.]
+
+Air must be admitted in limited quantity through the tap after
+the first thirty seconds or so; by a judicious regulation of this
+mechanism, anæsthesia may be prolonged for five or ten minutes.
+Facility with nasal gas comes only after some considerable practice.
+
+Fig. 17 shows Ash’s No. 3 Patented Nasal Inhaler, which admits of
+Air or Gas being administered either by the Naso-Oral Method, or by
+to-and-fro nasal breathing. _Air_ only is admitted when the Shutter A
+is open and turned to the right as far as it will go. _Nitrous Oxide_
+is admitted when the Shutter A is open and turned to the left as far
+as it will go, and the patient will breathe it in-and-out through the
+nose. _For the Nasal Oral Method_, close Shutter A and turn it to
+the left as far as it will go. This will cause the patient to inhale
+through the nose and exhale through the mouth.
+
+Nasal attachments are provided with most of the gas-oxygen apparatuses
+mentioned in the next chapter. With them good results can be obtained
+with much greater ease.
+
+For a more detailed account of nasal methods, the student is referred
+to works devoted entirely to Dental Anæsthesia.
+
+
+
+
+                             CHAPTER VIII.
+
+                       NITROUS OXIDE AND OXYGEN.
+
+
+The account given in the previous chapter of anæsthesia by nitrous
+oxide and air will have convinced the student that it is a somewhat
+inelegant method with a limited sphere of usefulness. The reason is
+obvious. In atmospheric air, oxygen exists only in the proportion
+of about one to four of nitrogen. To sustain life it is therefore
+necessary to admit to the anæsthetic mixture an amount of air which
+leaves too little room for the anæsthetic factor--nitrous oxide. If,
+however, pure oxygen be used, the nitrous oxide is diluted to a much
+less degree, and far better results are obtained.
+
+The exact scope for gas-oxygen anæsthesia cannot at present be defined
+with certainty. The work of Crile, and the experience of the war have
+done much to enlarge it. We may say that the following are definite
+indications for its use:--
+
+   (1) Minor operations lasting 5–15 minutes, particularly if
+   performed on out-patients.
+
+   (2) Operations of any variety upon the subjects of severe shock.
+
+   (3) Operations upon patients suffering from acute sepsis.
+
+   (4) Operations repeated upon the same subject at short intervals.
+
+As regards (3) and (4), the lack of toxic properties in nitrous oxide
+gas, and the rapidity with which it is eliminated, give it a tremendous
+advantage over ether or chloroform. To men with shattered bones and
+extensive damage to soft tissues, badly infected with sepsis, who
+required repeated opening up of pockets, changing of gauze packs, etc.,
+the advantage of gas-oxygen over ether was evident, and was easily
+appreciated by the patients themselves during the late war.
+
+There are, however, certain _drawbacks_ to the method which must be
+appreciated--
+
+   (1) The necessary plant is heavy, bulky, and costly; it cannot
+   be easily transported.
+
+   (2) The running cost is high as compared with ether or
+   chloroform.
+
+   (3) It has been said by some that gas-oxygen can only be given
+   by an expert. That is a statement too extreme, in the author’s
+   opinion. Certainly, of all anæsthetics it is the most difficult
+   to give successfully. Adequate study and proper teaching by an
+   expert are required, but given these two helps, any one can soon
+   learn to administer gas-oxygen for minor surgery. Considerably
+   more experience is, however, necessary before the beginner
+   should give it for an abdominal section.
+
+
+                              Apparatus.
+
+A good gas-oxygen apparatus is necessarily rather complicated. The
+machines in the market are numerous, and of the most diverse external
+appearance. Certain broad principles, however, underlie all the
+machines, and it is to be hoped that some one of them will before long
+become practically the standard. Once that is effected, hospitals and
+nursing homes could be expected to provide them. So long as every
+anæsthetist asks for a different machine, they certainly never will do.
+A good machine must provide means for the following:--
+
+   (1) _An even flow_ of both gases under perfect control.
+
+   (2) _A percentage of Oxygen_ in the mixture rising at the
+   will of the administrator from 2 to 15 or 20.[2] To meet this
+   requirement it is not necessary that any indicator should be
+   provided which shows with mathematical precision what percentage
+   of oxygen is being given. The colour of the patient tells us at
+   once if too much or too little oxygen is being supplied, and all
+   we need in the apparatus is some mechanism whereby we can tell
+   approximately to what extent we are increasing or decreasing the
+   percentage.
+
+   (3) _Positive Pressure._--If the pressure at which the gases are
+   supplied to the patient can be raised a little above that of
+   the ordinary atmosphere, absorption is increased and a deeper
+   anæsthesia produced. In the author’s view, this is an essential
+   point in a good instrument.
+
+   (4) _Re-breathing._--To supply the whole volume of gases
+   required for inspiration during a long operation is costly and
+   quite unnecessary. Yet that is what is being done if the whole
+   administration is conducted upon the “valvular” principle.
+   Moreover, a prolonged inhalation upon the valves tends to remove
+   a great deal of CO_{2} from the patient’s blood and tissues
+   (_see_ Chap. IV.). Periods of partial or complete re-breathing
+   do much to deepen respiration, and reduce the cost of the
+   anæsthetic.
+
+   (5) _Warming the Gases._--While not essential, this is certainly
+   an advantage.
+
+   (6) _Addition of Ether Vapour to the mixture._--Gas-oxygen
+   even well given is hardly capable of reducing to quiescence
+   very robust people, unless the oxygen percentage is kept to an
+   undesirably low level. The merest trace of ether vapour as an
+   adjunct is a great assistance during the stages of the operation
+   where very sensitive structures such as the parietal peritoneum
+   are being handled. The more experienced the anæsthetist, the
+   less will he require such assistance.
+
+                          Hewitt’s Apparatus.
+
+This, with the exception of one designed by Dr Guy and the author,
+and described on page 130, is the only machine with any pretence to
+portability by hand. It does not satisfy all the requirements above
+referred to, but the fact that it was the first practicable means
+introduced in this country to give gas-oxygen entitles it to full
+description. (_See_ Fig. 18.)
+
+  [Illustration: FIG. 18.--Hewitt’s gas oxygen
+  apparatus.]
+
+Essentially it consists of the following:--
+
+   (1) A supply of nitrous oxide and oxygen in separate cylinders.
+   Hewitt’s own stand held two of nitrous oxide and one of
+   oxygen.[3]
+
+   (2) Rubber pipes of supply for each of the two gases. For
+   convenience, it is sometimes arranged that one of these shall
+   run inside the other.
+
+   (3) Two 2-gallon bags. Nitrous oxide is led into the one, oxygen
+   into the other. The mouth of _each_ bag is guarded by an
+   inspiratory valve.
+
+   (4) The mixing chamber. Upon the surface of this are marked
+   successively: “Air,” “N_{2}O,” “O_{2}, 1 2 3 4 5 6 7 8 9 10.”
+   As the indicator is pushed from “air” to “N_{2}O,” the patient
+   begins to inhale nitrous oxide only, but as it travels into the
+   numerals 1, 2, etc., a proportion of oxygen is added.
+
+   Immediately below the mixing chamber is the _expiratory valve_.
+
+   (5) Lastly, there is the _facepiece_, identical with that used
+   for pure nitrous oxide.
+
+It would be fallacious to suppose that the numerals 2, etc., on the
+dial represent accurately the percentage of oxygen yielded by the
+instrument when the indicator points to one of these figures, nor
+did Hewitt ever make such a claim. What the figures do represent is
+a number of holes in the wall of the mixing chamber, opposite to the
+aperture from the oxygen bag, which are uncovered one by one as the
+indicator moves over. The amount of oxygen which enters into the mixing
+chamber is regulated by the number of these holes uncovered, and also
+by the tension of the oxygen bag. If the figure on the dial is to be
+even a rough index of the actual percentage of oxygen present in the
+mixture, it is necessary to keep the tension reasonably constant,
+_i.e._ to regulate the flow of oxygen from the cylinder by manipulation
+of the foot key. In a brief administration for, say, a dental case,
+this is not necessary. It is sufficient to fill the oxygen bag once,
+and then turn off the supply. If, however, a long administration is
+required, a constant flow of oxygen of just the requisite amount must
+be secured.
+
+
+                            Administration.
+
+Put the lever at “air,” and fill up each bag to an equal and moderate
+degree of distention. Adapt the facepiece accurately to the patient’s
+face, and then push the lever to “N_{2}O”. After a few inhalations,
+move to 2 of oxygen; regulate the flow of nitrous oxide from the
+cylinder so that the N_{2}O bag remains slightly distended. Gradually
+move the indicator along the numerals until the figure 6 or 8 is
+reached at the end of about a minute or a minute and a half. Women and
+children require more oxygen than men. The former are easily cyanosed;
+if the latter are fed too generously with oxygen, they are apt to
+become excited. Take as your guide to the amount of oxygen required the
+colour of the patient, the type of respiration, and the size of the
+pupil.
+
+The _colour_ aimed at can only be learnt by experience, but is best
+described as a dull pink.
+
+_The Type of Respiration._--Too little oxygen leads to stertor and even
+stridor; too much oxygen, to a light almost noiseless respiration,
+which to the experienced ear is the certain precursor of a stage of
+excitement. Such a stage is clear evidence of too much oxygen having
+been given.
+
+_The pupil_ should not be dilated to anything like the degree seen with
+undiluted nitrous oxide. A moderate distention only is to be desired.
+
+_Full Anæsthesia_ should be reached in 100–120 seconds. It is marked
+by:--
+
+   (1) Dull pink complexion; (2) full respiratory movements with
+   a stertor not exceeding that of gentle snoring; (3) eyeballs
+   rotated downwards; (4) moderately dilated pupils; (5) loss of
+   conjunctival reflex; (6) corneal reflex present but not very
+   active.
+
+If the object be the removal of a tooth, the mask may now be removed,
+and the dentist may rely upon a period of anæsthesia somewhat longer
+than that furnished by pure nitrous oxide. He ought to secure
+approximately one minute in which to do his work.
+
+Anæsthesia by this apparatus may however be prolonged for an
+indefinite time if desired. In order to maintain the patient in the
+condition described above, it will be necessary gradually to increase
+the supply of oxygen. For this purpose Hewitt added to his mixing
+chamber a supplementary oxygen supply giving 10 or 20 volumes of
+oxygen. As a matter of fact, all the necessary supply can be got
+through the original ten holes _if the tension in the oxygen bag
+be increased_. The regulation of all this requires, of course,
+considerable practice and experience.
+
+The signs upon which we rely for warning that the supply of oxygen is
+insufficient to keep the patient safe, are chiefly the colour of the
+face, which must not pass from dull pink to blue, and the size of the
+pupil.
+
+  [Illustration: FIG. 19.--Diagrams to illustrate
+  action of (A) Hewitt (B) Teter gas oxygen apparatus. Note
+  that in A the mouths of both bags are guarded by valves of
+  inspiration, while in B the oxygen bag only possesses it.]
+
+
+                  Deficiencies of Hewitt’s Apparatus.
+
+These are chiefly two:--
+
+   (1) There is no means of producing _positive pressure_. Any
+   attempt to distend the nitrous oxide bag beyond a certain point
+   simply leads to escape of the gas through the mixing chamber and
+   out of the expiratory valve even during inspiration. To this
+   defect especially must we attribute the fact that an anæsthesia
+   deep enough for abdominal section is difficult to secure with
+   the Hewitt instrument.
+
+   (2) There is no means of securing _re-breathing_. The whole
+   administration must of necessity be conducted “upon the valves.”
+   This latter fault is remedied by the modification introduced by
+   _Burns_, who took away the inspiratory valve from the mouth of
+   the N_{2}O bag, and fitted a cap over the expiratory valve which
+   could be rotated so as to throw the valve out of action. The
+   author first met this modification at a Base Hospital in France,
+   and found it a great improvement upon the original instrument.
+   It is, however, only an imperfect attempt to adopt Teter’s chief
+   principle.
+
+
+                    The Teter and Allied Machines.
+
+The rapid spread of nitrous oxide and oxygen anæsthesia in the
+U.S.A. brought forward a number of machines of which Teter’s was the
+forerunner; the other well-known machine of the group is the Clarke.
+They differ in principle from the Hewitt apparatus in that they permit
+re-breathing and the use of positive pressure. Diagrammatically, the
+two are contrasted in Fig. 19.
+
+  [Illustration: FIG. 20.--Details of the Clarke
+  Expiratory Valve. In the position of the lever marked “open”
+  the valve lifts easily and widely, and the breathing will
+  be purely valvular: in the position marked “half open,”
+  the valve lift is diminished, and the breathing is partly
+  valvular, partly to-and-fro. In the position “closed”
+  re-breathing only is possible.]
+
+The key to Teter’s advance is his removal of the inspiratory valve from
+the mouth of the nitrous oxide bag, and his substitution for Hewitt’s
+rubber expiratory valve, of a _rigid_ valve, the lift of which
+can be diminished or entirely abolished, at will (_see_ Fig.
+20). By damming, as it were, the flow from the expiratory valve, the
+administrator can oblige the patient to practise a certain amount of
+re-breathing, and, if he keeps up a free flow of the gases, he can
+develop a pressure in the nitrous oxide bag definitely exceeding that
+of the atmosphere.
+
+Teter also introduced into his apparatus a means to warm the gases, and
+to add a little ether vapour to the mixture when required.
+
+  [Illustration: FIG. 21.--The Clark gas oxygen
+  machine.]
+
+The Clarke machine is similar in principle to the Teter, but makes a
+strong point of the intimate mixture of the two gases produced in the
+mixing chamber which occupies the centre of the apparatus (Fig. 21).
+
+In both these machines, it will be observed, the two bags for N_{2}O
+and O_{2} respectively are attached to the stand, and the mixed gases
+are led to the patient by a pipe of wide bore. When re-breathing
+occurs, it must therefore be up and down this pipe, but the width of
+the bore seems to obviate any disadvantage which theoretically might be
+expected from this form of respiration.
+
+  [Illustration: FIG. 22.--Marshall’s sight-feed
+  gas-oxygen apparatus. Of the two glass bottles the one to the
+  left is the sight-feed, that to the right the ether chamber.]
+
+In the experience of the author and of many other anæsthetists, very
+good results can be obtained from either of these machines.
+
+
+                          Sight Feed Machine.
+
+In the author’s opinion, machines based upon this principle are likely
+to take a prominent place in the future of gas-oxygen. Fig. 22
+explains the simple mechanism. Each gas is led through a tube dipping
+into water contained in the sight feed mixing chamber. The ends of
+the pipes are open, and on the sides of each pipe also are a number
+of holes. If the pressure at which either gas is delivered is small,
+bubbles will be seen ascending towards the surface of the water from
+the upper holes only. The greater the pressure, the further down the
+pipe does the gas carry before all of it escapes through a hole, and
+one can therefore get an accurate estimate of the pressure from the
+number of holes through which the bubbles are seen escaping.
+
+Upon the surface of the water, the two gases meet and enter into
+mixture and are conveyed away by the third pipe which, of course, does
+not dip into the water.
+
+Once the eye of the anæsthetist is trained to its use, this is a very
+simple means of gauging the relative proportions of oxygen and nitrous
+oxide which are being delivered, and manipulation of the cylinder heads
+combined with visual inspection of the sight feed enable one to strike
+the right proportions very easily. The nitrous oxide is usually kept at
+a constant pressure sufficient to ensure bubbles, not only from all the
+side holes, but also a few from the open end of the tube. The oxygen
+pressure is begun at the point where there is a little bubbling from
+the top hole only, and is gradually increased until there is a full
+supply from two holes, occasionally a little even from a third.
+
+Messrs Coxeter have recently brought out two sight feed machines
+designed by Mr Leonard Boyle and Dr Geoffrey Marshall, of which the
+latter is shown in Fig. 22. This apparatus may be put up in either
+portable form or a larger type for use in hospitals. An ether chamber
+is provided for use when necessary in either type.
+
+As originally introduced, the remainder of the apparatus consisted
+simply of an ordinary two gallon bag, Barth 3-way tap, and rubber
+facepiece. With such an appliance, it is not possible to secure
+“positive pressure, a point which the author brought to the notice
+of the makers. Messrs Coxeter are willing to supply a facepiece and
+expiratory valve which obviate this defect, being supplied with a mica
+expiratory valve the lift of which can be controlled. There should be
+no inspiratory valve.
+
+
+    Administration of Gas-oxygen for the purposes of Major Surgery.
+
+The patient is prepared with the same scrupulous care as if ether
+or chloroform is to be administered. Half an hour before operation,
+morphia gr. ⅙ and atropine gr. ¹⁄₁₀₀ are given hypodermically. The
+anæsthetist before beginning administration, must look over the
+apparatus most carefully and satisfy himself that every part of it is
+in perfect order, and that a sufficient supply of both gases is at hand.
+
+The inhalation is begun by the use of nitrous oxide alone, given “on
+the valves,” and at no great pressure. After a few breaths, oxygen
+is added very guardedly, the proportion being steadily raised during
+the first two minutes: after that point, a further increase will not
+be necessary until several more minutes have elapsed. The pressure at
+which the mixture is being given is also steadily increased and should
+reach the maximum permissible within a few minutes. A useful plan
+is to allow the flow of gases to remain constant, but to close the
+expiratory valve at frequent intervals for about forty to sixty seconds
+at a time. During this period of complete re-breathing the tension in
+the supplying bag will of course rise, falling again slightly when the
+expiratory valve is allowed once more to come into action. As soon as
+the tension falls appreciably, the valve is again closed down.
+
+It is wise, particularly in one’s early days, to give a trace of ether
+vapour during the latter part of the induction stage, and to maintain
+it until the operation is well under way. Once the anæsthetist is
+satisfied that the narcosis is proving deep enough for the purposes
+of the operation, the ether may be shut off and will probably not be
+required again.
+
+Remember that _depth_ of anæsthesia can be secured in three ways--(1)
+cutting down the oxygen percentage; (2) increasing the tension of
+the mixed gases; (3) adding a little ether. Of these, No. 1 is most
+undesirable, and if carried to the least excess over a period of more
+than a minute or two may lead to an accident. No. 3 is the means for
+the beginner to rely upon, until he learns the judicious and skilful
+use of No 2. The anæsthetist who is learning the method of anæsthesing
+must resolve that nothing shall tempt him to overstep the stage of dull
+pink colour, and moderate pupils. If with gas-oxygen alone, he cannot
+get a satisfactory anæsthesia without resorting to oxygen starvation,
+let him not be ashamed to turn on his ether.
+
+Abdominal relaxation sufficiently complete to permit the surgeon to
+explore the abdominal cavity with ease, is not readily secured by
+gas-oxygen in a patient of robust type. Fortunately, it is the weakly
+or the severely shocked who really _need_ this form of anæsthesia, and
+in them abdominal relaxation is fairly easily obtained.
+
+Professor Crile, as has already been explained, does not rely upon
+the inhalational anæsthetic alone. He infiltrates each layer of the
+parietes with novocain, thus producing a local anæsthesia. If this
+method be faithfully carried out by the surgeon, a most complete
+relaxation of the muscles can be secured.
+
+
+
+
+                              CHAPTER IX.
+
+                                ETHER.
+
+
+The drug commonly known as ether and otherwise described as ethylic
+ether or sulphuric ether, has a chemical formula (C_{2}H_{5})_{2}O.
+It is a transparent colourless fluid with a specific gravity of ·720
+to ·723. A brand much used in the States has an S.G. of ·713 only, a
+point which is greatly emphasised by its supporters, who claim that it
+volatises quicker and therefore is more powerful in action. The author
+has in actual practise not found much difference between this brand and
+any good British one.
+
+Ether is highly inflammable and volatilises readily at ordinary
+room temperatures. Its boiling point is 96° to 98° Fahr. Whether
+evaporating from a fabric such as gauze, or from bulk in a jar, ether
+cools very rapidly, and the fall in temperature soon reduces the
+ease of its volatisation. This point is of some practical importance
+in anæsthetics, and some years ago the author made a number of
+observations, hitherto unpublished, with a view of ascertaining some
+definite facts in this connection. His results will be found in
+Appendix I.
+
+_Ether vapour_ is heavy--two and a half times heavier than air. It
+therefore tends in a room to flow towards the floor, and to remain
+for some time unmixed with the general atmosphere. Since it is highly
+explosive, this constitutes a definite danger if any naked light or
+open fire is present. Everyone who handles ether should bear in mind
+these physical peculiarities of its vapour.
+
+Ether is affected by prolonged exposure to bright sunlight, and also by
+prolonged bubbling through it of air, nitrous oxide, or oxygen. Ether
+which has been subjected to any of these measures should be inspected
+before being put back into reserve, and if any brown discoloration
+is noticed, it should either be sent to the hospital laboratory for
+redistillation, or presented to the theatre sister for use as a
+cleaning agent. Such contributions are always gratefully received.
+
+Most of the ordinary impurities of ether are acid in reaction, while
+ether itself is absolutely neutral. Any specimen which turns litmus
+paper red should be sent to the laboratory for examination.
+
+
+                          Sources of Supply.
+
+Ethylic alcohol may be prepared either from ethyl alcohol or from
+methylated spirits. In the former case it carries, however, the cost
+of the duty imposed upon potable spirit, and since perfectly good
+anæsthetic ether can be prepared from the latter source, it is waste of
+money to use the more expensive article.
+
+
+                              Physiology.
+
+Ether acts upon the nervous system like other anæsthetics: as compared
+with chloroform, however, the stage of excitation of each centre
+before its paralysis is apt to be marked. There is, therefore, in some
+subjects, a greater tendency to struggle; healthy subjects properly
+handled do not show much evidence of irritation of the cerebrum. All,
+however, show some evidence of stimulation of the respiratory centre,
+which is not prolonged. _Prolonged deep and rapid respiration under
+ether is due to other causes than the action of the drug itself._ It
+is of course seen in “closed ether,” but the active agent is excess of
+CO_{2}, not ether.
+
+The working margin of safety in ether, _i.e._ the stage between loss of
+spinal reflexes and the poisoning of respiratory centre is much wider
+than in chloroform.
+
+Some experiments of Waller made many years ago showed that upon nerve
+tissue, ether acts much less powerfully than chloroform: in the
+proportion, he found, of one to seven or eight. These laboratory
+results have received entire confirmation by later workers who have
+estimated the actual vapour strength required of either drug to produce
+or maintain anæsthesia. Roughly, to induce anæsthesia, we require 2 per
+cent. chloroform, or 16 to 18 per cent. of ether (_see_ Appendix II.).
+
+
+                           The Circulation.
+
+The first effect of ether is a temporary stimulation of the heart,
+which beats more rapidly and more strongly, thus raising the blood
+pressure. This effect is not very prolonged; like all other drug
+stimulation, it is followed by depression. In the healthy subject
+properly anæsthetised, such depression is very moderate in degree, and
+in a normal administration it is probable that the heart, after the
+first few minutes, is acting very much at its normal speed and force.
+Ether is, however, a marked vaso-dilator, and the net result upon blood
+pressure is a slight fall after the first few minutes.
+
+If the method in use is “closed,” the pressure remains slightly raised
+for some considerable time, usually throughout the administration. The
+slight anoxaemia induces a vaso-constriction; and the CO_{2} excess,
+in the view of Henderson (_see_ page 10), maintains a good return of
+venous blood to the heart and a satisfactory cardiac output. For a note
+of certain blood changes resulting from ether and other anæsthetics
+(_see_ Appendix III.).
+
+
+                          Respiratory System.
+
+In addition to the effect upon the medullary centre already referred
+to, ether effects the respiratory tract more profoundly than other
+anæsthetics. The mucous membranes are irritated, and in some cases
+there is a great outpouring of mucous. Though usually limited to the
+upper part of the tract (nose, pharynx, and trachea), the irritation
+sometimes extends deeply into the chest, affecting even the small
+bronchioles. These unpleasant effects of ether are in the great
+majority of cases, quite transient: after the first ten minutes no
+addition to the secretions is noticed. In a minority, however, the
+effect persists, the whole chest is filled with moist sounds, and
+persistence with the drug is impossible.
+
+_The kidneys_ are always slightly irritated by ether, and if they
+are or recently have been subject to inflammatory disease, a very acute
+exacerbation is apt to follow the use of the drug. In the healthy
+kidney this is not to be feared, nor does it seem to be an appreciable
+danger where one kidney is sound, even if the other is the seat of
+gross organic disease necessitating its drainage or removal.
+
+  [Illustration: FIG. 23.--Clover’s ether inhaler, with nitrous
+  oxide attachment.]
+
+
+                      Methods of Administration.
+
+Many methods have been tried, but those which at present hold the field
+are--
+
+   (1) Closed Ether.
+
+   (2) Open Ether, more properly called the Perhalation Method.
+
+   (3) The “Vapour” Method.
+
+   (4) The Rectal Method (Gwathmey’s oil-ether).
+
+   (5) The Intratracheal Method, described separately in Chapter
+   X.
+
+  [Illustration: FIG. 24.--Diagram of a vertical section through
+  the middle of Clover’s Inhaler. A. shows the ether dome; B.
+  Central tube removed from apparatus]
+
+                           (1) Closed Ether.
+
+The two inhalers originally brought out for this were Clover’s in
+London, and Ormsby’s in Dublin. At a later date Hewitt’s “wide bore”
+modification of the Clover was introduced.
+
+(_a_) _The Clover instrument_ (see Fig. 23)[4] consists of a
+face-piece, a dome-shaped ether chamber, and a one-gallon bag, usually
+attached to the top of the ether chamber by a =T=-shaped tube. The
+details of the method by which the amount of ether inhaled by the
+patient is graduated are best appreciated by unscrewing the milled
+head at the top of the dome, and withdrawing the tube which runs
+through it (_see_ Fig. 24). In the tube will be found two slots, one
+about half an inch above the other, and each extending for half the
+circumference of the tube. Between these two slots the tube is divided
+by a diaphragm. In any case, therefore, air passing up or down the tube
+must pass in and out of these slots.
+
+Now turn to the tubular space left in the dome piece, and examine
+visually and with the finger its interior. On the one side of its
+middle will be found two slots leading into the circular ether chamber
+which occupies a large part of the dome. On the other side will be
+found a small cavity, as deep from above downwards as the two slots
+combined, but _not_ communicating with the ether chamber. It is obvious
+that with the tube inside, if this cavity is opposite the slots in
+the tube, air will pass up the tube out of one slot and back into the
+other, without coming into contact with the ether at all. If on the
+other hand the slots in the tube are opposite the slots in the ether
+chamber, the air passes over the surface of the contained ether, and
+volatises some of it.
+
+Intermediate positions of the tube give a condition where part only
+of the air passes over the ether. The indicator attached to the tube,
+combined with the figuring “O, one, two, three, full,” to be found
+on the outside of the base of the dome, shows at any moment what
+proportion of the air is passing into the ether chamber.
+
+To use the instrument, fill the metal measure provided with ether,
+withdraw the stopper from the ether chamber, and pour in the ounce
+and a half of ether which the measure contains. Replace the stopper,
+and blow through the tube to expel any ether vapour which may have
+appeared in it. Leave the rubber bag at first unattached: the patient
+will feel more comfortable if during the first minute the top of the
+tube is open. With the indicator at 0 adapt the face-piece to the face
+and allow the patient to breathe up and down the tube. By rotating
+the dome, ether is then gradually turned on, until the figure two
+is reached in the first minute. The indicator is then slipped back
+nearly to zero for a second, and the rubber bag slipped on during
+an _expiration_: it must be moderately inflated to supply the
+requisite volume of air for respiration.
+
+  [Illustration: FIG. 25.--Hewitt’s wide-bore ether
+  inhaler.]
+
+The rotation of the dome is again begun and the indicator is made to
+travel away from the zero, until at the end of about five minutes, it
+reaches “full.” After the first few minutes, it will be necessary to
+give an occasional breath of fresh air, otherwise an undesirable degree
+of cyanosis will result, but it must be done with great discretion, or
+struggling will ensue. At the end of about five minutes, anæsthesia
+should be fully established. A little extra ether is then poured
+into the chamber, the indicator pushed back to about “two” and the
+administration continued. One breath of fresh air is given in every
+three or four. Spells may be given with the bag off altogether, but
+during such periods the indicator will require to be advanced a little,
+and refills of ether provided more frequently than would be necessary
+if the bag were on.
+
+
+                          Hewitt’s-wide-bore.
+
+The principle of this is identical with that of the Clover, but the
+channels being wider, there is less mechanical interference with the
+ingress and egress of air. The actual construction differs also, in
+that to turn on the ether, instead of rotating the dome, one moves the
+indicator (_see_ Fig. 25). The instrument certainly gives results
+a little better than those obtainable by the Clover, but it is heavier,
+and rather more bulky.
+
+
+                   Ormsby’s Inhaler (_See_ Fig. 26).
+
+This consists of a facepiece, a cage made of wire or thin steel slips
+and containing a sponge; and lastly, a one gallon bag which fits
+over the cage. In the face-piece is an air vent, which can be either
+entirely closed, partially or entirely opened.
+
+  [Illustration: FIG. 26.--Ormsby’s Inhaler. The cage
+  for the sponge does not show in the figure, it projects
+  upwards from the bag-mount, and is therefore enclosed in the
+  bag.]
+
+To use the instrument, take out the sponge and warm it either by
+wringing it out of hot water, or better by leaving it a few minutes on
+the top of a hot steriliser. Push it back into the cage, open the air
+vent fully, and holding the inhaler upside down, pour on to the sponge
+a measure full (about half an ounce) of ether. Tell the patient to
+inhale deeply, and then catch the resulting expiration in the bag by
+quickly adapting the facepiece to the face at the appropriate second.
+
+After a few seconds, begin to close the air vent, when it will be
+found that the bag begins to wax and wane with each expiration and
+inspiration respectively. After the first three minutes, the inhaler
+must be removed, more ether poured in, the air vent opened again
+partially, and the inhaler again applied to the face. After full
+anæsthesia is induced, the air vent may constantly be left partially
+open.
+
+_N.B._--It must be observed that the air vent is not valved: it is
+merely an opening through which part of the respired air may pass in
+and out without going near the ether sponge.
+
+In actual practice, the induction stage of closed ether is almost
+invariably assisted by using either nitrous oxide, or a small dose of
+ethyl chloride as a preliminary: these methods are described in Chapter
+XV.
+
+The question now arises, what _scope_ is to be assigned in modern
+anæsthesia, to closed-ether methods. Formerly a large proportion of
+anæsthesias, long or short, were conducted by the closed method, and
+while the greater number of anæsthetists no longer utilise them to the
+same extent as formerly, they may still be regarded as of the utmost
+value in a limited class of cases. They are speedy in action, powerful
+enough to overcome the most refractory patient, and with reasonable
+skill very safe. On the other hand, the anæsthesia obtained is not
+of the most desirable type. There is a great deal of salivation and
+mucous secretion from the respiratory mucous membranes; the respiratory
+movements are deeper than in open methods, from the excess of CO_{2}
+present in the blood, and this leads to a good deal of heaving of
+the abdominal wall, which may be most troublesome to the surgeon
+if he is opening or closing that cavity. Moreover, after their use
+more headache, malaise, and vomiting occur than after open-ether, and
+perhaps a little more tendency to bronchitis or pneumonia. For these
+reasons, many anæsthetists and surgeons now object to their use in
+abdominal surgery, though some still adhere to them for the induction
+stage, passing to the open method when the patient is once well under.
+
+
+                            (2) Open Ether.
+
+As already explained the strictly accurate term for this is
+Perhalational Ether, but so cumbersome a terminology stands small
+chance of general acceptance.
+
+
+                              Apparatus.
+
+The essential points in a proper outfit have already been explained
+(_see_ page 28) and are all well met by the mask and ether dropper
+introduced by Mr Bellamy Gardner (_see_ Fig. 27). The mask is covered
+with from twelve to sixteen layers of gauze, and lies on the gauze
+ring, shown in the Fig. 28A, which completes the fit between face and
+facepiece. The dropper fits into the ordinary six ounce dispensary
+bottle: the long arm dips into the ether, the short one allows air
+to enter the bottle to replace the ether used. A dropper can also be
+improvised by using a cork with slots cut at each side and with
+a gauze or wool wick inserted along one of these. The author finds
+these uncertain in their action, however: with Gardner’s dropper, a
+steady flow of _drops_ of ether slow or fast as required, can always be
+obtained once the student has acquired the knack of using the appliance.
+
+  [Illustration: FIG. 27.--Bellamy Gardner’s (A) open ether
+  mask; (B) ether dropper.]
+
+  [Illustration: FIG. 28.
+
+  _A._--Open ether. Ready to begin.
+
+  _B._--Open ether. Condensing towel in position.]
+
+  [Illustration: FIG. 28.
+
+  _C._--Open ether. Correct method of holding mouth and jaw.
+
+  _D._--Open ether. Alternative method of holding mask.
+  The towel and gauze have been removed so as to show the
+  tilting of the mask which this method is liable to cause.]
+
+To Mr Bellamy Gardner’s outfit, the author adds a folded towel, pinned
+at one corner, so as to form a short cone. The base of this cone
+embraces the mask and face; through its upper apperture the anæsthetic
+is dropped on to the mask. The cone can be rotated into the position
+most convenient for this purpose in any given position of the patient’s
+head (Fig. 28).
+
+
+                   Problems of the Induction Period.
+
+Open-ether is not a powerful anæsthetic, just not powerful enough for
+one to be sure that one can induce full anæsthesia with it alone, in a
+powerful subject. The reason for this is shown in Appendix II, and may
+be here condensed by explaining that some 18 per cent. to 20 per cent.
+of ether vapour is required to induce anæsthesia, while it is not easy
+to get more than 14 per cent. off an open mask. How is this situation
+to be met?
+
+Reference has already been made to one solution of the problem. _A
+closed ether method may be used for induction_, and this practice is
+widely used. The author does not often adopt this course, fearing that
+the undesirable features of closed ether may persist even after the
+change to an open method has been made.
+
+Another possibility even more widely favoured is to use _chloroform as
+the inducing agent_, and only to turn to ether when full anæsthesia
+is obtained. To this plan the author is strongly opposed. It exposes
+the patient to the risks of the induction stage of chloroform which
+are much greater than those of the later stages. Moreover, to develop
+the full advantages of open-ether, a preliminary hypodermic of morphia
+is essential, and the drawbacks of chloroform _plus_ morphia are
+elsewhere mentioned (page 43).
+
+The use of a _mixture of chloroform two parts, ether three parts_,
+presents the same disadvantage, but in a degree so much smaller that
+in powerful or alcoholic patients, the author believes this to be the
+method of choice (_see_ Chapter xiv.).
+
+_Dr Silk_ has recently suggested another plan. He has sought to make
+open-ether easy for the non-expert with a view of encouraging the
+wider use of so valuable a method. For this purpose he advocates the
+admixture of one part of chloroform in thirty-two of ether (a dram of
+chloroform in four ounces of ether). This is to be given in exactly the
+same way as perhalational ether, and will, Silk says, give a type of
+anæsthesia, and a degree of safety, identical with those of pure ether.
+The author’s experience with Silk’s mixture is too limited to enable
+him to offer any opinion upon its merits.
+
+Lastly, there remains the plan of using _ether as the main inducing
+agent_, but assisting its action by the intermittent and most guarded
+addition of small quantities of C_{2}E_{3} mixture. This is the
+author’s “stock” method; but in teaching it to students, too much
+emphasis cannot be laid upon the small quantities of chloroform mixture
+required or _permissible_. _As a consequence of the perhalational
+method here advocated, every drop of chloroform which appears on the
+mask will when volatilised, give a very much higher percentage of
+CHCL_{3} vapour in the inspired air, than the same quantity exhibited
+on the ordinary open chloroform mask._ Once the student has grasped
+this essential fact, ordinary care and intelligence will enable him to
+guard against a danger which is only existent if unappreciated.
+
+
+                          The Administration.
+
+For many of the hints given in this section the author is indebted to
+Dr W. J. Ferguson of New York, and Dr Hornabrook of Melbourne.
+
+Success in inducing with open-ether is attained only by attention to a
+number of small details. The student who thinks that some of these are
+too trifling for his notice is usually the man who informs you that
+induction by open-ether is impossible, the fact really being that he
+has not taken the trouble to learn, or has never had proper tuition.
+The following are the points demanding attention:--
+
+   1. Always give a dose of morph-atropine or other narcotic, half
+   to three-quarters of an hour beforehand.
+
+   2. See that the patient is comfortable on the table. Prop up his
+   head and shoulders a little with pillows. In powerful subjects
+   Hornabrook tilts the whole table down at the foot-end, for a few
+   degrees.
+
+   3. Adhere strictly to perhalation and to the drop method. You
+   will never induce with open-ether if the whole volume of the
+   respired air does not pass through the gauze.
+
+   4. Chat to the patient as long as consciousness can possibly
+   persist. Tell him he is doing very well. Don’t shout complicated
+   instructions at him as to how to breathe: it annoys and muddles
+   him.
+
+   5. When the gauze ring and the mask are in position, allow one
+   or two drops of ether to fall on the mask, then pause: in a few
+   seconds the mild ether vapour so formed will soothe the upper
+   respiratory tract, and prepare it for the stronger vapours yet
+   to come. This does not waste time--it saves it.
+
+   6. When the administration is again begun, attend closely to
+   the rate of dropping. At first not more than one drop in three
+   or four seconds is wanted. The full rate of dropping cannot be
+   attained for at least ninety seconds.
+
+   7. Give no mixture for the first ninety seconds; thereafter some
+   five to ten drops every half minute or every twenty seconds
+   according to type of patient. Have the mixture bottle handy so
+   that no time is wasted in changing bottles. Stop the addition of
+   mixture as soon as full anæsthesia is attained.
+
+   8. Slip the folded towel over the mask and tuck its base well
+   round the chin and face. Do this only after the first two
+   minutes have elapsed.
+
+   9. As soon as the neck muscles are relaxed, turn the patient’s
+   head over to one side, and let the hands assume the position
+   described in Chapter iii. and illustrated in Fig. 28C.
+
+   10. The student is warned to discourage the too early attentions
+   of the nurse or house-surgeon. These officials are naturally
+   anxious to “get the patient ready for the Chief” and are
+   apt to start “cleaning up” before the patient has lost all
+   consciousness. A man who is doing his level best to go to sleep,
+   derives neither pleasure nor profit from a wholly unexpected dab
+   of ice-cold methylated spirit upon his umbilicus.
+
+By the use of the method here advocated, induction is singularly easy
+and successful in good subjects. The struggling stage is either not
+represented at all, or appears only in the form of the lifting of
+a limb and a slight occasional pause or catch in respiration. Full
+anæsthesia is often announced audibly, by the commencement of a gentle
+“blowing.” Once it is heard, the anæsthetist may rest assured that a
+workable level of anæsthesia is either present or not far off.
+
+
+                      Amounts of Ether required.
+
+If the above instructions are followed, the amount of ether required
+is not excessive. Anæsthesia is attained after the use of about 1½ to
+2 ounces of ether and one or two drams of mixture. The next forty to
+fifty minutes demand about another four or five ounces of ether; no
+mixture at all. Some practice, is required before these small figures
+are attained. The more practice, the less ether is required.
+
+
+                       III.--VAPOUR ANÆSTHESIA.
+
+In a sense, all forms of ether anæsthesia are vapour methods, but
+in all the forms so far described, the patient has to vapourise the
+drug for himself: in a true vapour anæsthesia this is done for him,
+and the mixture of air and ether vapour propelled towards him. One
+of the keenest advocates of this method is Dr Gwathmey, of New York.
+He lays great stress also upon the necessity of warming the vapour,
+claiming that this measure will prevent the loss of heat to the patient
+incidental to the warming up in the air passages of the cold vapour
+usually supplied by other methods; but the results of the laboratory
+experiments upon which Gwathmey founded his case are inapplicable to
+the human subject, in that they were performed upon dogs and cats,
+which lose heat largely from the mouth and air stream. Man is not a
+hairy animal, and transacts most of his thermolysis through the medium
+of his skin. None the less, warming the vapour of ether has value since
+the process removes some of the irritant effects so marked in the case
+of cold ether vapour.
+
+
+                   Apparatus for the Vapour Method.
+
+In 1913, Karl Connell described such an apparatus, which was then in
+use at the Roosevelt Hospital, New York. The ether was vapourised by
+dropping it into a warm chamber. Air was pumped into the chamber, and
+carried the ether vapour in known percentage, and at known pressure as
+shown by gauges. Such mechanism is ideal, but would certainly be rather
+costly. Its great value was that it informed us with certainty what
+proportions of ether in the atmosphere were necessary to induce and
+maintain anæsthesia (_see_ Appendix II.).
+
+A simple mechanism was brought out shortly afterwards by Dr Shipway, of
+Guy’s, and is known as Shipway’s warmed Ether.
+
+It consists essentially of the following parts (_see_ Fig. 29):--
+
+   (1) A small hand bellows (B).
+
+   (2) An ether bottle, with tube for delivery of air stream
+   dipping deeply into the fluid: the exit tube of course does not
+   dip in. The bottle stands in a metal pan in which water at about
+   75° Fahr. is to be placed (E).
+
+   (3) A thermos flask (W) in which is a metal tube (U). The
+   etherised air passes along this tube, and picks up heat from its
+   walls. The thermos is filled with water at about 180° Fahr.
+
+  [Illustration: FIG. 29.--Shipway’s warmed ether vapour
+  apparatus.]
+
+   (4) A mask upon which a towel or gauze is to be stretched: the
+   rubber tube bringing the air and ether is brought through the
+   covering material and delivers the anæsthetic vapour in the
+   region of the mouth.
+
+   (5) Additional to the above, there may be added a small
+   chloroform bottle (C). In specimens of the instrument containing
+   this convenience, there has, of course, to be a regulating tap
+   (T) at the head of the ether bottle, which will divert more or
+   less of the air stream towards the chloroform.
+
+This little machine, somewhat resembling a cruet stand in its
+appearance was widely used in France. Owing to the kindness of
+the Edinburgh Red Cross Committee, one was provided for the Base
+Hospital with which the author proceeded to Salonika, where he used
+it extensively. The impression of it formed by himself and others
+was that it was peculiarly easy to maintain with it a steady level
+of anæsthesia. It had, however, no claim to banish post-anæsthetic
+bronchitis and pneumonia, of which in spite of much anxious care and
+thought, a fair number of cases were seen during the winter time
+(_see_ page 151).
+
+In using the machine, it is necessary to remember that from the
+physical point of view, one is providing from the machine a small part
+only of the total volume of air required by the patient.
+
+The bellows are quite small: one squeeze of the hand will not supply
+more than about the equivalent in volume of one or two fluid ounces.
+The larger part of the volume required by the patient has to be
+obtained from the general atmosphere, so that the percentage of ether
+which may be as high as 25 in the exit tube, will be greatly lowered by
+the time it reaches the patient’s respiratory tract.
+
+       *       *       *       *       *
+
+The actual strength of ether breathed by the patient will depend upon:--
+
+   1. The force and frequency with which the pump is compressed.
+   (_N.B._ It is of course useless to pump during expiration).
+
+   2. The depth of ether in the bottle.
+
+   3. The temperature of the water bath in which the ether bottle
+   stands. The warm water should only be put in at the last moment
+   before starting, otherwise very strong ether vapour will collect
+   on the surface of the ether, and the first puff of the bulb will
+   expel a highly irritant vapour towards the patient.
+
+With specimens of this machine which have the addition of the
+chloroform bottle, it is perfectly possible to conduct even the
+induction stage of anæsthesia; a mere trace of chloroform vapour will
+be sufficient. It is unnecessary to give detailed instructions for the
+use of the machine. A preliminary consideration of the above physical
+facts, together with a little cautious practice, will enable the
+student rapidly to acquire facility with the method.
+
+
+                       IV.--RECTAL ETHERISATION.
+
+For such operations as the removal of jaw or tongue there are obvious
+advantages in being able to introduce ether vapour to the blood per
+rectum, since the mouth and air passages are thereby left free for the
+attention of the surgeon.
+
+Many years ago this was attempted by vapourising ether and propelling
+the vapour through a tube high up into the rectum. This method was
+abandoned, as it led to a good deal of inflammatory trouble afterwards.
+Recently, Dr Gwathmey suggested a new method of utilising the rectal
+route which has largely overcome this objection.
+
+
+                     Gwathmey’s Oil Ether Method.
+
+This consists in passing into the rectum a mixture of olive oil and
+ether. The bowel is first carefully washed out, and an hour before
+operation, the patient receives a hypodermic of morphia, gr. ⅙;
+atropine, gr. ¹⁄₁₂₀. A suppository of chloretone gr. v is also passed
+into the rectum to act as a local sedative. Half-an-hour later, the
+patient is put into the left lateral position, a soft catheter
+attached to a funnel is passed some six inches up the rectum, and the
+mixture of oil and ether poured into the funnel. It is wise to take at
+least five minutes to introduce the whole dose.
+
+The following table shows the dosage required:--
+
+    +------------------+-------------+------------------------------------+
+    |                  | Strength of |                                    |
+    | Age of Patient.  | Ether in    |  Quantity of Mixture required.     |
+    |                  | Mixture.    |                                    |
+    +------------------+-------------+------------------------------------+
+    | Under 6 years    | 50%         |  One ounce to each 20 pounds body  |
+    |                  |             |  weight (no preliminary morphia)   |
+    |                  |             |                                    |
+    | 6 to 12 years    | 55% to 65%  |      Do.                do.        |
+    |                  |             |                                    |
+    | 12 to 15 years   | Do.         |  One ounce to each 20 pounds body  |
+    |                  |             |  weight (but use ¹⁄₁₂ gr. morphia) |
+    |                  |             |                                    |
+    | 16 years and     | 75%         |  One ounce to each 20 pounds body  |
+    | upwards          |             |  weight with ⅙ gr. morphia as a    |
+    |                  |             |  preliminary                       |
+    +------------------+-------------+------------------------------------+
+
+In practice then, for the ordinary adult, one uses eight ounces of the
+mixture, six ounces of which are pure ether. The oil and ether require
+to be shaken together, but remain blended long enough for introduction.
+
+In five or ten minutes, the patient begins to feel a rather pleasing
+numbness and tingling in the lower, and later the upper extremities,
+and drops quietly to sleep in about twenty minutes. In a large
+proportion of cases, it is necessary to deepen the anæsthesia by the
+use of the open mask for a few minutes, but once a deep anæsthesia has
+been thus obtained, the absorption from the rectum will balance the
+loss in expiration and maintain a good anæsthesia for three quarters of
+an hour at least.
+
+On return to bed of the patient, the nurse passes two tubes placed side
+by side, as high into the rectum as she can; the end of a Higginson
+syringe is inserted into one of them, and a considerable quantity of
+soap and water is pumped gently into the bowel, escaping down the
+second tube. The washing must be continued until all smell of ether
+is removed. Finally the soapy water itself is washed away by a little
+saline.
+
+Unless there be some pre-existing local inflammatory disease of the
+rectum (in which case the method should not be used), there are no
+unpleasant sequelæ after oil ether. The chief objection to the method
+is the amount of labour thrown on the nursing staff, which is so
+considerable as to bar it from adoption as a routine. This should not,
+however, be allowed to prevent its use in the limited number of cases
+in which it is strongly indicated. These are:--
+
+   (1) Panic-struck cases who cannot face the ordeal of ordinary
+   methods.
+
+   (2) Nose, throat, and tongue operations where intratracheal
+   ether is not available.
+
+
+
+
+                               CHAPTER X
+
+                  INTRATRACHEAL INSUFFLATION OF ETHER
+
+
+Intratracheal insufflation consists in driving a current of air under
+pressure, through a tube introduced by way of the mouth and larynx,
+deeply into the trachea. The current of air which is continuous,
+returns between the tube and the wall of the trachea, and escapes
+through the mouth and nose.
+
+
+                   Certain Physical Considerations.
+
+The work of Meltzer and Auer has demonstrated that this insufflation of
+air into the trachea under adequate pressure ventilates the pulmonary
+alveoli, and enables the normal diffusion of gases to be carried out
+for many hours, independently of all respiratory movements. If the
+air in its passage under pressure is made to pass through a chamber
+containing ether, we are enabled to introduce into the pulmonary
+alveoli, ether vapour of varying strength, and, by this means, to
+maintain surgical anæsthesia.
+
+       *       *       *       *       *
+
+THE ACTUAL PROCESS OF EXTERNAL RESPIRATION consists in the absorption
+of oxygen from the alveoli into the blood of the lung capillaries, and
+the elimination of carbon dioxide from the lung capillaries into the
+alveoli. The oxygen has to be brought from the outside to the alveoli,
+and the carbon dioxide has to be conducted from the alveoli to the
+outside. Between the outside and the alveoli is the long airshaft,
+consisting of mouth and nose, pharynx, larynx, trachea, bronchi and
+bronchioles. In natural respiration the conduction of oxygen inwards,
+and of carbon dioxide outwards, is carried through by a complicated
+pumping mechanism. In ordinary inhalation anæsthesia, this mechanism is
+entrusted with the task of introducing ether vapour into the alveoli.
+
+In intratracheal insufflation the work of this natural pumping
+apparatus is taken over by an artificial mechanism. In considering the
+justification for this, the following points are to be noted:--
+
+   (1) The patient is unconscious--not naturally so as in
+   sleep--but unnaturally as the result of drugs; there is
+   therefore a probability that the elaborate natural mechanism
+   may not work smoothly--especially is there a danger that the
+   free airway may be interfered with. Intratracheal insufflation
+   obviates this danger.
+
+   (2) By means of the artificial mechanism, air is brought with
+   some force to the mouth of the bronchi, and thus a more rapid
+   and more powerful diffusion of gases takes place.
+
+   (3) The mechanism ensures the maintenance of a current of air
+   blowing forcefully from the trachea and larynx through the
+   pharynx, mouth and nose. This re-current continuous air-stream
+   effectively prevents the entrance of blood or any infectious
+   material into the bronchi and air cells, and thus the danger of
+   septic lung troubles is obviated.
+
+   (4) In certain intrathoracic operations the normal respiratory
+   mechanism is deliberately interfered with. Intratracheal
+   insufflation by the constant maintenance of sufficient positive
+   pressure, prevents or regulates the collapse of the lung
+   which occurs when the thorax is opened, and thus obviates the
+   necessity for the somewhat elaborate positive and negative
+   pressure cabinets and masks which had been devised for
+   intrathoracic operations.
+
+   (5) Incidentally it may be noted that intratracheal insufflation
+   of air provides us with an excellent means for performing
+   artificial respiration. Many instances have now been recorded
+   of its utility in this respect. Dr Elsberg records the case
+   of a patient who had taken morphia with suicidal intent, on
+   whom artificial respiration by this method was kept up for 12
+   hours, without any respiratory movements taking place, recovery
+   ultimately ensuing.
+
+
+                            The Apparatus.
+
+This consists of (_see_ Fig. 30):--
+
+   1. Instrument for producing air current (A).
+
+   2. Ether chamber and various regulating taps (B).
+
+   3. Device for warming vapour (C).
+
+   4. Safety valve (D).
+
+   5. Manometer (E).
+
+   6. Intratracheal catheter, with rubber tubing linking up the
+   various parts of the apparatus (H).
+
+  [Illustration: FIG. 30. Diagram of intratracheal apparatus.]
+
+1. THE AIR CURRENT is obtained either by means of an ordinary
+glass-blower’s foot bellows, or an electric motor may actuate a
+rotatory blower which produces a current of air. The blower may be made
+to rotate at a speed varying from 50 to 1000 revolutions per minute
+(_see_ Fig. 31).
+
+The foot bellows is simple and inexpensive, and there is no reason why
+it should not be efficient. The electrically rotated blower is more
+efficient, ensures a smoother air current, and saves much labour.
+
+2. THE ETHER CHAMBER.--Ether vapour may be produced by either of two
+methods. Fig. 32 shows Kelly’s instrument where air is blown over the
+surface of a considerable quantity of liquid ether. Dr Meltzer[5]
+maintains that the effectiveness of the etherization is proportional
+to the diameter of the ether bottle. In this connection it may be well
+to recall certain points pertinent to the subject of etherization. A
+satisfactory etherization depends on the establishment in the blood
+and tissues of an ether tension of definite strength. Boothby[6]
+states that this tension should correspond to about 15 per cent. of
+ether vapour in the alveolar cells. “If when this tension has been
+established, less than 15 per cent. ether vapour is administered,
+outward diffusion occurs from the tissues and blood to the air and the
+anæsthesia becomes lighter.”
+
+  [Illustration: FIG. 31.--Electric blower to supply current of
+  air for intratracheal anæsthesia.]
+
+  [Illustration: FIG. 32. Kelly’s intratracheal apparatus.]
+
+In an apparatus such as we are describing the strength of the ether
+vapour depends on and is influenced by a variety of factors, among
+which the following may be specially noted:--
+
+   (_a_) _The diameter of the ether chamber._--The larger the
+   diameter the stronger will be the ether vapour. The chamber is
+   generally kept two-thirds full: the less the empty space in the
+   chamber the stronger will be the vapour.
+
+   (_b_) _The rapidity of the air-current._--The larger the amount
+   of air passing over the ether the more rapid will be the
+   vapouration, with the result that the temperature of the liquid
+   ether will rapidly fall and the strength of the ether vapour in
+   the air will be correspondingly lowered.
+
+   (_c_) _The temperature of the liquid ether._--The higher the
+   temperature of the liquid ether the stronger will be the
+   percentage of ether vapour in the air. If the ether chamber is
+   placed in a bath of water which is maintained steadily at an
+   adequate temperature and if the rate of the air flow remains
+   constant, a constant strength of ether vapour will be given off.
+   It is well in this connection to remember that the boiling
+   point of ether is low and that a very high percentage of ether
+   vapour is readily obtained if the temperature in the water
+   bath is allowed to rise beyond 80°F. For further information
+   regarding ether percentages _see_ Appendix I and II.
+
+Such an instrument as Kelly’s requires at its head a _regulating tap_,
+movement of which is capable of diverting part of the air stream direct
+to the patient without coming in contact with the surface of the ether.
+In this way the maximum strength of vapour may be diluted as and when
+required.
+
+In Fig. 33 is shown Shipway’s instrument. Here the drug is dripped
+into a chamber, the floor of which is kept warm. The ether volatilises
+at once and the vapour is carried away by the air stream passing
+through the chamber. The strength of ether vapour in this instrument is
+regulated solely by the rate of drip which is in complete control of
+the administrator.
+
+Whichever method of making ether vapour is utilised the instrument
+should be capable of producing a maximum at least of 15 per cent. to 18
+per cent., and means must be provided to reduce this percentage at will.
+
+3. DEVICE FOR WARMING VAPOUR.--It is doubtful if the warming of
+inspired or insufflated vapour has any appreciable influence on
+the body temperature, but there is a fairly general consensus of
+opinion that if the ether vapour is warmed there is less likelihood
+of irritation of the respiratory mucous membrane. It is to be noted,
+moreover, that in intratracheal insufflation the natural apparatus for
+warming the inspired air is put out of action. This warming can be
+effected by the simple device of carrying the tube through a chamber of
+hot water after it emerges from the ether chamber.
+
+4. SAFETY VALVE.--Dr Meltzer insists very strongly on the necessity
+of having a safety valve capable of controlling the maximum pressure
+under which the air may enter into the intratracheal tube. By a
+simple device, any excess of desired pressure will cause the air to
+bubble through mercury and thus never reach the lungs. In this way any
+possibility of accident from undue intrapulmonary pressure is obviated.
+
+  [Illustration: FIG. 33.--Shipway’s intratracheal
+  apparatus.]
+
+5. MERCURY MANOMETER to indicate the pressure in the tube in m.m.
+of mercury. It has been experimentally established[7] “that the
+pressure in the trachea and in the bronchi is only a small fraction
+of the pressure in the manometer outside of the body, and that the
+intratracheal pressure grows considerably less with the decrease of
+the diameter of the intratracheal tube.”
+
+6. INTRATRACHEAL CATHETER.--It is essential to have an instrument of
+adequate rigidity which can be satisfactorily sterilized. The ordinary
+coudé catheters, or the silk web white enamelled cylindrical catheters,
+are suitable. The size should be selected from a range of 18 to 25
+French. It is preferable to err rather on the side of a small than a
+large tube. An ordinary adult will require a tube of about size 22 to
+24, a plethoric alcoholic, on the other hand, might need a 25.
+
+A tube of too large a calibre interferes with the free return of air
+and spontaneous respiration soon becomes too slow. Expiration is
+prolonged, active, and laboured, and after a few minutes, respiratory
+movements may cease entirely. The only way to meet such a situation is
+to withdraw the tube and insert a smaller one.
+
+TECHNIQUE OF ADMINISTRATION.--It is advisable in adults to administer
+about three quarters of an hour before the operation, a hypodermic
+injection of morphia (gr. ⅙) and atropine (gr. ¹⁄₁₀₀), or of
+scopolamine (gr. ¹⁄₁₀₀) and morphia (gr. ⅙). The latter combination is
+more efficacious in alcoholic subjects. In children, atropine alone
+should be given.
+
+It is to be remembered that intratracheal insufflation of ether is a
+method of maintaining not of inducing anæsthesia. Induction is carried
+out in the ordinary way. When this has been done, the catheter is
+passed.
+
+The introduction of the catheter does present some difficulty, but
+this is largely overcome as skill and confidence are acquired with
+practice. It may be carried out indirectly, or a view of the glottis
+may be obtained by the aid of such an endoscope as Hill’s, and the
+catheter inserted between the cords. The latter method is probably the
+more satisfactory, but it is well to acquire the skill to pass the
+catheter indirectly as in a certain small proportion of cases there are
+obstacles to the use of the endoscope.
+
+To facilitate catherization the pharynx and epiglottic region may
+be cocainized with a 5 per cent. solution before induction. Hill’s
+endoscope (Fig. 34) is distally illuminated by a small electric lamp,
+which is connected with a small pocket battery. A useful modification
+of this has been devised by Mr Dott. In it, the catheter is passed
+along a separate compartment, so that the view of the glottis is
+undisturbed. The point of the catheter comes into view at the distal
+extremity of the endoscope and can be guided between the cords into the
+trachea.
+
+  [Illustration: FIG. 34.--Hill’s Direct Laryngoscope.]
+
+It is essential before attempting intubation, that there should be
+thorough relaxation. The lower jaw should be so slack that a gag is not
+required. The head is then placed in the occipito-shoulder position, or
+is allowed to hang over the end of the table. The tongue is controlled
+by forceps, and the endoscope passed slowly along its dorsum until the
+epiglottis comes into view. The point of the endoscope is then passed
+sufficiently far below the tip of the epiglottis to ensure that it will
+not slip; too deep insertion must be avoided. The endoscope being held
+in the left hand, the hyoid bone is lifted up by a tilting movement of
+the hand. The glottis is thus brought into view. The catheter stiffened
+by means of a probe is then passed through the glottis into the
+trachea and the endoscope withdrawn. The bifurcation of the trachea in
+the adult is at a distance of about 26 cm. from the incisor teeth. The
+catheter should be marked accordingly, and inserted to a point just
+short of this. The probe is then withdrawn, and connection made with
+the air current.
+
+It occasionally happens that unexpected difficulty is met with on
+attempting to pass the catheter by direct vision. The larynx may be so
+fixed that the glottis does not readily come into view; or in the case
+of an intraoral neoplasm the view may be obstructed by the presence of
+blood. In such cases the catheter can be introduced by the indirect
+method. The middle finger of the left hand is passed along the dorsum
+of the tongue until the epiglottis is felt. The index finger is then
+used to guide the point of the catheter to the glottis through which
+it is then passed. No undue force must be used. A stilette should be
+inserted into the catheter which should be moulded almost to a right
+angle at its terminal third. If the stilette is withdrawn when the
+point of the catheter is over the mouth of the glottis, the instrument
+will, as a rule, slip easily into the trachea.
+
+Occasionally the tube passes into the œsophagus. With care and adequate
+relaxation such a mistake should not occur, but the possibility of it
+should be kept in mind. If the operator will abstain from attempting to
+pass the catheter until such time as he has a satisfactory view of the
+glottis, mistakes of this kind will seldom occur. The essentials are a
+good illumination and an adequate relaxation.
+
+Mild glottic spasm may supervene on the passage of the catheter but
+this rapidly passes off. At first the degree of concentration of the
+vapour should be low or irritation will result, evidenced by spasm and
+coughing. The strength of the vapour is gradually increased until the
+necessary concentration is attained. The pressure should vary according
+to the requirements of the case and should range between 10 mm. to 25
+mm. Hg. The safety valve must be set so as to make any pressure above
+this impossible.
+
+In the majority of cases the course of anæsthesia is smooth and
+uneventful; the colour remains a rosy pink, the pulse is good, and the
+respirations quiet and regular. It is undesirable that the respiratory
+movements should be abolished altogether; their presence indicates that
+neither the central nor the peripheral respiratory mechanism is being
+overdosed with ether.
+
+Theoretically, the constant plus-pressure in the lungs might be
+thought to interfere with the circulation in the large veins, and
+in the pulmonary vessels themselves. It is therefore well to reduce
+the pressure in the catheter to zero every minute by opening the tap
+provided for the purpose for a second or two.
+
+At the conclusion of the operation, before withdrawing the catheter
+it is well to flush out the lungs with air so as to remove any ether
+vapour that is present. In a certain number of cases, notably in
+big alcoholic subjects, difficulty may be experienced in securing
+a sufficiently deep anæsthesia with good relaxation. It is seldom,
+however, that patience and the careful introduction of a stronger
+vapour will not suffice to overcome this. In alcoholic subjects, as
+previously suggested, preliminary medication with scopolamine and
+morphia will help. It really becomes a question, if one may put it
+so, of coaxing the unconscious patient to tolerate an ether vapour of
+adequate strength.
+
+
+                  Advantages and Special Indications.
+
+The general opinion of anæsthetists appears strongly to favour the view
+that the absence of strain and the perfect æration in intratracheal
+ether insufflation tend to lessen the shock of operation. The
+post-operative history of patients also suggests that there is a
+lessened liability to pulmonary complications as compared with cases
+in which ether has been administered by other methods. Dr Elsberg[8]
+of New York in this connection writes: “The absence of any pulmonary
+complications has led us to use this method of anæsthesia in all
+patients in whom pulmonary complications were to be feared after an
+anæsthesia or operation. Thus on all asthmatics, in patients with
+chronic bronchitis and emphysema, in patients who require gastric
+resection and the like, we no longer, during two years, have seen the
+much dreaded post-operative pneumonia wherever intratracheal anæsthesia
+was used.”
+
+In addition, there is ample evidence[9] that the introduction of a
+catheter into the trachea and its presence therein does not tend,
+as might have been expected, to set up any irritation at the time
+or predispose to subsequent trouble. Apart from these general
+considerations, which suggest the advantage of a somewhat extended use
+of intratracheal ether insufflation, the method has obvious advantages
+in all operations about the mouth, such as those for excision of the
+upper jaw, those undertaken for the removal of nasopharyngeal growths
+and various plastic operations involving the nasal and buccal cavities.
+In such cases the danger of aspiration of blood, mucus, etc., is
+obviated and the anæsthetist is well out of the surgeon’s way, while at
+the same time an even interrupted delivery of ether vapour is effected.
+In operations for removal of glands in the neck the surgeon has the
+field to himself, and is not hampered nor is his asepsis endangered by
+the proximity of the anæsthetist’s mask.
+
+In such operations as laminectomy and nephrectomy the postural
+difficulties with which the anæsthetist has to contend, and which also
+tend to interfere with free respiration, are eliminated.
+
+The great advantage of the method in intrathoracic operations has
+already been referred to.
+
+The introduction of intratracheal insufflation of ether was rendered
+possible by the pioneer work of Drs Elsberg, Meltzer, and Auer. The
+writer would like to acknowledge his indebtedness to their writings, of
+which he has made free use.
+
+
+
+
+                              CHAPTER XI.
+
+                              CHLOROFORM.
+
+
+                       Physical Characteristics.
+
+Chloroform is chemically trichlor-methane, CHCL_{3}. It is a
+colourless, transparent fluid, with a specific gravity of 1·491 at
+17°C. Its vapour is even heavier than that of ether, approximately
+four times heavier than air. It is not inflammable, but the action of
+an open fire or naked flame tends to break it up into hydrochloric
+acid and phosgene, both of which are highly irritant gases to all who
+breathe them. The patient suffers, but since all the other occupants of
+the theatre are also affected, warning is given before serious harm has
+been inflicted.
+
+Chemically pure chloroform is a somewhat unstable product, but the
+addition invariably made to it by the producers, of a trace of
+alcohol, prevents any serious risk of decomposition in bulk. It should
+be neutral in reaction and have an agreeable non-irritating odour:
+departure from the normal in either respect indicates the possibility
+of the presence of acids or aldehydes, and the necessity for referring
+a specimen to the laboratory.
+
+Like ether, chloroform may be obtained from pure ethyl alcohol or from
+methylated spirits, and the remarks made in the chapter upon ether
+apply to the case of chloroform also. A third source of supply is
+acetone, from which perfectly good chloroform can be produced.
+
+
+                              Physiology.
+
+Chloroform is an irritant to the skin and mucous membranes. A drop left
+on the skin and covered over with impermeable material will produce a
+deep and painful blister. A drop falling into the eye, if not instantly
+washed away, produces a very powerful inflammatory reaction, and many
+eyes have been totally lost from carelessness in this respect. Such
+incidents are of course actionable, and heavy damages may be given.
+
+  [Illustration: FIG. 35.--Diagrammatic representation of
+  various blood pressure curves obtainable with chloroform.
+
+  Line ABA′ represents curve desired in normal chloroform
+  administration.
+
+  Line ABCB′ represents gradual overdosage.
+
+  Line ABCC′ represents recovery by inversion.
+
+  DD′ represents syncope from vagal inhibition: in its course,
+  one attempt of the heart to “escape” is shown.]
+
+The special peculiarities of the action of chloroform upon the nervous
+system have already been emphasised in the account given of the
+physiology of ether (see page 75). Its action upon the _circulatory
+and respiratory systems_ has been the subject of many researches,
+and of much embittered controversy. The literature is therefore very
+extensive, and the account of it must be severely condensed. The
+following may be taken as a brief resumé of present day opinion (_see_
+Fig. 35):--
+
+   (1) In every case of chloroform administration, there is a fall
+   of blood pressure.
+
+   (2) If the drug be presented in weak concentration (less than 2
+   per cent. vapour strength), the fall is gradual and even (line
+   AB).
+
+   (3) If the same strength (say 2 per cent.) of vapour as produced
+   the above effect be prolonged unduly, the respiration will cease
+   at a time when blood pressure is still well above zero (line
+   ABCB′).
+
+   (4) The fall of pressure is due to diminished force of cardiac
+   action, and at a later stage also to vaso-motor paresis.
+
+   (5) The cessation of respiration is due partly to fall of
+   blood pressure in the vessels supplying the medullary centre;
+   partly to gradual poisoning of the centre itself by the drug.
+   That the fall of B.P. in the cerebral vessels is in itself one
+   explanation of the cessation of respiration, was proved many
+   years ago by Leonard Hill in his inversion experiments. Just
+   at the stage when respiration had ceased, the anæsthetic was
+   withdrawn, and the animal inverted into the head-down position.
+   The B.P. in the carotid at once began to rise, and natural
+   respiration was resumed (line A′BCC′).
+
+The above conclusions refer to chloroform given in moderate vapour
+strength; other effects are produced if higher percentages are
+administered:--
+
+   (6) With high concentration of chloroform vapour, the fall
+   of blood pressure is rapid, and is apt to become suddenly
+   precipitous (line DD′).
+
+   (7) The cause of these sudden falls is inhibition of the
+   heart by over-activity of the vagus: cutting the vagi always
+   terminates the effect unless delayed so long that the animal is
+   dead: in an animal fully under atropine, these vagal actions
+   cannot be produced.
+
+   (8) If the heart is inhibited by vagal action, the respiration
+   ceases at once, usually after one deep inspiratory sigh.
+
+   (9) An inhibited heart may “escape” from vagal action before the
+   animal is dead: frequently, however, the inhibition persists and
+   the animal dies.
+
+   (10) Struggling and breath-holding in the early stages of
+   induction cause sudden falls of blood pressure. Many observers
+   believe that these falls also are due to vagal activity, others
+   hotly deny this. All are united in believing that to _press_
+   chloroform upon a patient who is struggling and holding the
+   breath, is fraught with grave risk of causing sudden syncope.
+
+   (11) The abnormal irritability of the vagus above referred to is
+   a feature mainly of the induction stage, disappearing once full
+   anæsthesia is developed.
+
+   (12) It is an undoubted clinical fact that there is a risk
+   of sudden arrest of heart’s action if the operation is begun
+   before the stage of full anæsthesia is reached. A reasonable
+   explanation of such accidents is furnished by supposing a reflex
+   inhibition acting through the vagal centre already rendered
+   hyper-sensitive by partial chloroformisation.
+
+
+                        Views of Goodman Levy.
+
+This worker has demonstrated in animals that the heart is sometimes
+thrown by chloroform into the condition of fibrillation--a delirium
+of the cardiac muscle, from which recovery is rare. It occurs in
+the early stage, before full anæsthesia has been reached, and is
+predisposed to by the infliction of trauma. The practical outcome of
+this is that the induction stage of chloroform should not be unduly
+prolonged, and that the operation should not be begun until the third
+stage is fully developed.
+
+So far as the author understands the views of Dr Levy, his explanation
+of chloroform syncope need not be taken as introducing any new
+principle into the administration of the drug. Even those who lay most
+emphasis upon the danger of using vapours of too high a percentage
+strength would admit the force of Levy’s contentions. As usual, safety
+lies in steering between two extremes.
+
+During his work on this subject, Levy further demonstrated that
+the introduction into the circulation of _adrenalin_ during
+incomplete chloroform anæsthesia was very liable to induce fatal
+cardiac fibrillation. He thus furnished the explanation of a number
+of deaths which had occurred in the practice of nose and throat
+specialists. Since the publication of Levy’s work, the rule has been
+absolute that if _adrenalin_ is to be used in a case requiring
+chloroform anæsthesia, the adrenalin must _precede, not follow_
+the anæsthetic.
+
+
+                            Administration.
+
+Basing upon these views as to the action of chloroform, and upon the
+lessons of practical experience, we may formulate definite rules for
+giving the drug.
+
+
+General Principles for giving Chloroform.
+
+   (1) Give chloroform evenly, not spasmodically.
+
+   (2) Increase the vapour strength of chloroform gradually from
+   zero until 2 per cent. or at most 2½ per cent. is reached at the
+   end of two or three minutes; maintain that strength until full
+   anæsthesia is obtained; thereafter, drop down to 1–1·5 per cent.
+   This will result in a B.P. curve corresponding to the line ABA′
+   in the diagram (Fig. 35).
+
+   (3) Be guided chiefly by the patient’s respiration. Chloroform
+   kills by stopping the heart, but in the immense preponderance
+   of cases, evidence of failure of respiration appears in ample
+   time to give warning of approaching circulatory failure. The eye
+   reflexes give confirmatory evidence of the depth of anæsthesia,
+   but the superlatively important thing is to _maintain a free
+   airway, and be sure the patient is using it_.
+
+   (4) If serious struggling and breath-holding occur, withdraw the
+   anæsthetic until the patient “resumes normal.”
+
+
+                      Methods of Administration.
+
+The logical application of such general principles would be to use an
+instrument which gives a definite and known percentage of chloroform,
+variable at the wish of the administrator. Many such machines have
+been brought forward, and while none of them have obtained general
+acceptance, a description of the best known instrument will be given,
+as the reader may as a house-surgeon meet with it, and with a surgeon
+who wishes it to be used.
+
+
+                      Vernon Harcourt’s Inhaler.
+
+In principle, this is a “draw-over” instrument; the patient’s own
+inspirations are the motive power. Passing over the surface of the
+fluid drug, the inspired air picks up from it a known percentage of
+vapour. The other system available for the construction of percentage
+chloroform instruments is the “plenum”; in this the vapour is propelled
+to the patient by a pump.
+
+  [Illustration: FIG. 36.--Vernon Harcourt’s Percentage
+  Chloroform Inhaler.]
+
+In appearance, the inhaler resembles the letter T, with a rubber
+face-piece attached to the lower end of the vertical limb (_see_ Fig.
+36). The T portion itself is made of metal tubing of a definite size
+in cross section. One end of the horizontal limb admits pure air, the
+other, air which has passed over chloroform and picked up from it a
+certain proportion of vapour. The proportion of the total inspired
+volume of air which passes through each of the ends is regulated by
+a lever seen at the junction of horizontal and vertical limbs, and
+the exact percentage of chloroform being inhaled is indicated by a
+series of numerals marked on the dial over which the lever moves. These
+figures are correct provided:--
+
+   (1) The chloroform receptacle is not shaken (this would greatly
+   increase the percentage).
+
+   (2) The temperature of the chloroform is not allowed to fall
+   below 13° centigrade. To ensure that this cannot take place
+   without the knowledge of the administrator, two coloured beads
+   are thrown into the chloroform. At the desired temperature of
+   the chloroform (13°–15°C) the blue bead sinks to the bottom,
+   the red one nearly to the bottom. Below 13°C, the red bead also
+   touches bottom, and when this is observed, the chloroform vial
+   is warmed up in the palm of the hand. At the point 15°C, both
+   beads float, and the warming must then stop, or an undesirable
+   addition to the vapour strength yielded will occur.
+
+The face-piece is made of rubber, and must be closely adapted to the
+face; in its side is seen the expiratory valve. Inspiratory valves are
+present at each end of the horizontal limb.
+
+The great advantage of this instrument, to the author’s mind, is for
+teaching or demonstration purposes. If the student _sees_ the lever
+gradually being moved over from ·2 to 2 per cent., then slipped back to
+about 1·5 per cent. after full anæsthesia has been obtained, he begins
+to appreciate what it is he is aiming at when giving chloroform by the
+ordinary open method.
+
+  [Illustration: FIG. 37.--Schimmelbushch’s mask.]
+
+
+                             Open Method.
+
+The appliances requisite are:--
+
+   (1) A mask. Schimmelbushch’s is the best known (Fig. 37): as
+   elsewhere explained, it does not accurately fit the face.
+
+   (2) Material to stretch on the mask. The best is two layers of
+   domette or one of flannelette: surgical gauze is so light that
+   heavy drops of chloroform are apt to “spark” through it and burn
+   the skin of the face: lint rapidly becomes sodden; the drug
+   drips away from its edge instead of vapourising properly.
+
+   (3) A good drop bottle, of which many varieties are marketted
+   (Fig. 38): it is essential that it should be capable of
+   producing definite _drops_: the old method of intermittent
+   “douching” of chloroform is to be condemned as violating the
+   first general principle for giving the drug.
+
+  [Illustration: FIG. 38.--Chloroform drop bottles.]
+
+It is not possible by the open method to be mathematically accurate
+with percentages, but the necessary appliances are simple, easily
+transported, and practically always at hand. If the student learns to
+use it, and while doing so _to think in percentages_, he will
+achieve as good results as or better than he will with percentage
+instruments. While he may not have in front of his eyes a dial which
+shows the percentage graphically, observation of the patient will
+inform him whether the percentage being given should be maintained,
+raised, or lowered. The only remaining point for him to realise, then,
+is how in practice such regulations of percentage strength can be
+achieved by the open method. The strength of the vapour will depend
+upon three factors:--
+
+   (1) Nature of the material used on the mask.
+
+   (2) Closeness with which the mask is adapted to the face.
+
+   (3) Amount of chloroform exhibited on the mask.
+
+To ensure uniformity of result, two of these factors should be kept
+constant, and the necessary increase or decrease of vapour strength
+achieved by varying the third. Always use the same type and thickness
+of material on the mask, and allow the mask to lie lightly on the face.
+If the amount of chloroform is then regulated by a strictly “drop”
+method, results of great uniformity may be obtained by the open method.
+
+
+                          The Junker Inhaler.
+
+This instrument was originally introduced as an attempt to achieve a
+percentage method. Air is pumped through a certain depth of chloroform
+contained in a bottle, and the vapour brought to the patient in the
+face-piece shown in Fig. 39. The calculations by which it was sought
+to establish this as a reliable dosimetric or percentage method are of
+no great value. From that standpoint the instrument has not achieved
+success. It delivers to the patient a _small quantity of high
+percentage vapour_ which is diluted by a much larger quantity of
+air inspired by the patient from the general atmosphere, and the final
+percentage inhaled by the patient is therefore no more accurately known
+to the administrator than in the open method.
+
+The instrument is, however, of considerable value for tongue and jaw
+cases, where anæsthesia has to be maintained for some considerable
+time after the mask with which anæsthesia has been induced has had to
+be removed, to give access to the surgeon.
+
+  [Illustration:
+
+  FIG. 39.--Junker’s Chloroform Inhaler showing hand
+  bellows, bottle and mask. Alternatively to the latter, the
+  nasal tube shown above, may be used.]
+
+The Figure 39 shows the instrument as usually marketed. It consists
+of:--
+
+   (1) A hand-bellows.
+
+   (2) Chloroform bottle. A mark cut on this shows the level to
+   which it is to be filled: if more than the proper quantity be
+   poured in, droplets of fluid chloroform are apt to be blown
+   along the exit tube, with dangerous results.
+
+
+
+For convenience and neatness, it is usual to make the exit surround
+the inlet tube. The entering air bubbles through the chloroform,
+and a stream of air and chloroform vapour passes out from the exit
+tube.[10] It is unnecessary to give a detailed account of the use of
+the instrument, but the student must remember the following points:--
+
+   (1) The amount of chloroform vapourised will depend on the
+   vigour of the pumping, the depth of fluid, and the temperature
+   of the chloroform. In order to achieve uniform results, it
+   is therefore necessary to keep up a steady but not excessive
+   pumping, to warm up the bottle occasionally by holding it in the
+   palm of a disengaged hand, and to watch that the level of the
+   chloroform does not fall too low.
+
+   (2) The pumping should be timed to synchronise with inspiration:
+   a puff of vapour delivered during an expiration will be wasted.
+
+
+              Advantages and Disadvantages of Chloroform.
+
+The light portable appliances which are alone necessary for chloroform
+anæsthesia, the comparative cheapness of the method, and the _apparent_
+ease with which its administration may be conducted, are all great
+temptations to its use. Those who feel the temptation strong upon them
+are advised to remember the following quotation from the writings of
+Professor Leonard Hill:--
+
+“Chloroform is a drug used by the young anæsthetist with the utmost
+hardihood, and until he has had the misfortune in his practice to meet
+with a death caused by it, he derides the danger of the drug, and
+asserts that its safety merely depends on the care and skill of the
+administrator. After losing his patient, he falls to descanting on the
+unavoidable dangers of the drug, dangers which he is now the first to
+maintain cannot be met by any degree of skill in administration.”
+
+The most distressing and probably the most common chloroform fatalities
+are exemplified in administration given for the most trifling
+conditions, such as opening abscesses or extracting teeth.
+
+In general, we use chloroform if for any reason ether is not
+applicable. For examples of cases of this description, the reader is
+referred to the chapter upon the choice of anæsthetics.
+
+
+
+
+                             CHAPTER XII.
+
+                            ETHYL CHLORIDE.
+
+
+Chemically this drug has the formula C_{2}H_{5}Cl. It is a colourless
+fluid so volatile that it boils at ordinary room temperature. Its
+vapour is highly explosive, and the fluid itself very inflammable. The
+drug is supplied by the makers in small tubes with a metal end which
+can be opened by pressing a little lever (_see_ Fig. 40), varying
+in type with the brands made by various makers. Two brands are sold
+by each firm; one is chemically pure, intended for use as a general
+anæsthetic; the other is not so pure, and is only sold for local
+anæsthesia. Such a product is not suitable for inhalation.
+
+  [Illustration: FIG. 40.--Tube of Ethyl Chloride.]
+
+
+                              Physiology.
+
+The special points in the physiology of ethyl chloride may be briefly
+summarised as follows:--
+
+   1. After a trifling preliminary rise, the effect of the drug
+   is to lower the blood pressure appreciably. In the human adult
+   subject, this fall becomes appreciable when more than 3 c.c.
+   have been given; if the dose exceed 5 c.c. a fall of 30 to 40
+   mm. of Hg. is probable,--occurring as it does within a period of
+   perhaps twenty or thirty seconds, such a fall cannot be regarded
+   as safe.
+
+   2. The cause of this fall is diminished cardiac output from
+   weakening of heart muscle. The vagus though not paralysed, does
+   not appear to be unduly irritable, as it does with chloroform.
+
+   3. The respiratory centre is at first perceptibly stimulated,
+   and respiration is therefore deeper and quicker than normal. The
+   stimulant effect rapidly passes away and gives place to a stage
+   of depression.
+
+In the majority of cases, death appears to take place from paralysis
+of the respiratory centre, the heart still showing a little power of
+contraction after respiration has ceased. There is therefore a fair
+prospect of recovery if artificial respiration be resorted to promptly.
+
+
+                      Methods of Administration.
+
+
+                             OPEN METHOD.
+
+The extreme volatility of the drug has discouraged most anæsthetists
+from giving it upon an open mask. Hornabrook, of Melbourne, advocates
+this system, however. His mask fits the face accurately, and his whole
+method is strictly perhalational. He uses some 4–6 c.c. of the drug
+for a child, 6–8 c.c. for an adult, and achieves his anæsthesia in a
+minute to a minute and a half. He also advocates open ethyl chloride
+as a preliminary to open ether. For some twelve months, the author
+adopted the method. At the end of that time he came to the conclusion
+that while it greatly facilitated the induction stage of open ether,
+it appeared to increase the after sickness. He therefore abandoned it,
+though rather reluctantly.
+
+
+                            CLOSED METHOD.
+
+This is the usual means employed. A variety of inhalers have been
+produced on the market, one of which is shown in Fig. 41. Essentially
+all consist of:--
+
+   (_a_) A face-piece which must fit the face with reasonable
+   accuracy.
+
+   (_b_) A one-gallon rubber bag attached to the mask by a
+   T-piece.
+
+   (_c_) A glass vial, with numerals from 1 to 5 marked on the
+   outside to facilitate the measurement of the drug in c.c. Into
+   this the drug is squirted from the makers’ tube. The vial is
+   attached to the T-piece (or alternatively the bottom of the bag)
+   by a rubber tube.
+
+  [Illustration: FIG. 41.--Ethyl Chloride Inhaler.]
+
+
+                            Administration.
+
+To use such an inhaler, the glass vial is first detached from the
+rubber tube, and the chosen dose of drug squirted into it. A child
+of five or six will require 3 c.c., an adult up to 5 c.c.; this dose
+should never be exceeded. The vial is then rapidly reconnected with
+the inhaler. The face-piece is adapted to the face, care being first
+taken to place between the teeth a mouth prop or a gag. This enables
+one to get immediate access to the mouth when the inhaler is removed.
+The patient is then told to breathe deeply once or twice. During the
+inspiration the mask is lifted slightly, and the ensuing expiration is
+then caught in the bag by pressing down the mask on to the face. To
+volatilise the drug there are two alternative methods. In the one, part
+or the whole of the dose is tipped into the rubber bag by elevating the
+vial. A far better is the “Vapour” method, almost universally used in
+Edinburgh owing to the advocacy of Dr Logan Turner. A tumbler is filled
+with hot water, and the bottom of the glass vial is allowed first to
+touch, and after a few seconds to be immersed in it. Some thirty to
+forty seconds suffice to vapourise the whole of the dose.
+
+Ethyl chloride given by itself should always be administered to a
+patient in the recumbent position. A dose sufficient to produce
+anæsthesia without the aid of nitrous oxide or ether will not be safe
+in the erect posture. The case is quite different where a small dose
+only is given, to assist the action of nitrous oxide, or facilitate the
+induction stage of ether.
+
+
+                         Signs of Anæsthesia.
+
+Ethyl chloride is very rapid in its action, some sixty seconds
+availing to produce quite a deep anæsthesia. _Respiration_ is
+at first deepened and quickened: as full anæsthesia is attained it
+remains rather deeper than normal, and is accompanied usually by light
+snoring. The colour should remain perfectly good: the pupils show
+marked dilatation, the corneal reflex is abolished, and good muscular
+relaxation is attained.
+
+With no anæsthetic is it so essential as with this, to become
+acquainted with the type of respiration normally to be expected, and to
+watch for any departure therefrom with cat-like vigilance. The other
+danger signal is the pupil. It should be dilated, but a rim of iris
+should still be perceptible.
+
+Once anæsthesia is established, the inhaler should be removed, and the
+surgeon may begin his work. He will have for its completion some 80–90
+seconds against the 40–50 available after nitrous oxide. With ethyl
+chloride there is a somewhat prolonged “analgesic” stage. The patient
+is partly conscious and may even be phonating, but seems unconscious of
+the infliction of pain unless very severe measures are being used.
+
+
+                     The Scope of Ethyl Chloride.
+
+When first introduced, it was expected by enthusiasts that the
+lightness and portability of the drug itself and of the necessary
+inhaler, would enable ethyl chloride to oust nitrous oxide from its
+recognised place in surgery and dentistry. These high expectations
+have for several reasons not been fulfilled. In the first place, this
+drug is essentially a “single dose” anæsthetic. Most authorities view
+coldly all attempts to prolong anæsthesia by repeated or continued
+administration. Secondly, ethyl chloride has a mortality rate very
+much greater than nitrous oxide if doses sufficient in themselves to
+produce anæsthesia are habitually used (_vide supra_). The introduction
+of the “vapour” method has done much to mitigate the risks, but even
+then, this anæsthetic cannot approach the high level of safety rightly
+credited to N_{2}O. Moreover, it leads to after vomiting much more
+commonly than its rival.
+
+In many schools these considerations have been held so powerful that
+ethyl chloride has been entirely abandoned. It is, however, a very
+valuable drug for the following purposes:--
+
+   (1) The removal of tonsils and adenoids. For this operation,
+   the speed with which the patient (usually a child) loses
+   consciousness, the pleasant type of anæsthesia and absence of
+   all serious asphyxial phenomena, and the rapid re-appearance
+   of the cough reflex when once the inhaler is removed, are all
+   strong recommendations.
+
+   (2) As an adjuvant to gas, or gas oxygen (_see_ Chapter
+   XIII.).
+
+   (3) As a help to the speedy and comfortable induction of “closed
+   ether” (_see_ Chapter XV.).
+
+
+
+
+                             CHAPTER XIII.
+
+             MIXTURES OF NITROUS OXIDE AND ETHYL CHLORIDE.
+
+
+Dr Guy, Dean of the Edinburgh Dental School, introduced some years
+ago a method of giving ethyl chloride in mixture with nitrous oxide.
+Guy’s objective was to utilise the many excellent features of the drug
+without incurring the risks which are apparently inherent in it when
+a dose sufficient in itself to induce full narcosis is used. Given in
+mixture with gas, a much smaller dose suffices.
+
+  [Illustration: FIG. 42.--Guy’s inhaler for N_{2}O and Ethyl
+  Chloride.]
+
+His original apparatus is shown in Fig. 42, the details are shown in
+Fig. 43. The horizontal limb of a 3-way gas tap is prolonged half an
+inch. In each side of the prolongation is a hole. The bag mount has
+in its side also one hole, which is connected by a universal ball and
+socket joint, with the rubber tube to which the ethyl chloride vial is
+attached. An indicator on the outside of the bag mount and a mark upon
+the outside of the horizontal limb of the 3-way tap, serve by their
+apposition or the reverse to show whether the ethyl chloride vial is in
+direct continuity with the interior of the inhaler. For purposes of
+description, Dr Guy calls these two positions, “in register” and “out
+of register.”
+
+To use the instrument, the ethyl chloride vial is removed, and the side
+pipe attached to a cylinder of nitrous oxide. The indicator of the
+3-way tap is put at “air” and the bag mount “in register.” The bag is
+then filled with gas by opening the head of the cylinder. The bag mount
+is now put “out of register,” and the side tube disconnected with the
+cylinder. The bag, being closed, remains full of gas.
+
+  [Illustration: FIG. 43.--Guy’s Instrument for Gas and Ethyl
+  Chloride. Details of valve piece and bag mount, showing side
+  tube for attachment of Ethyl Chloride vial.]
+
+A suitable dose of ethyl chloride is now squirted into the vial. To
+an adult, Dr Guy gives 3 c.c.: on no account is this dose exceeded:
+children take 1½–2 c.c.--even adults often get less than 3 c.c. The
+vial is now attached to the side tube again, and the inhaler is ready
+for use.
+
+After application of the mask to the face, the 3-way tap is at once
+pushed over to “no valve” and the patient rebreathes the gas in and out
+of the bag for some six or eight respirations. The bag mount is now
+turned round “into register,” and the ethyl chloride tipped into the
+bag. In a further twenty-five seconds the mask may be removed and the
+operation begun.
+
+The available period of anæsthesia is eighty to ninety seconds,
+counting from the instant of the removal of the inhaler.
+
+This method was in use for some years at the Dental Hospital of
+Edinburgh; no instance of danger to life was ever seen. With so small a
+dose of ethyl chloride, the erect position necessary for the purposes
+of dentistry is perfectly safe.
+
+  [Illustration: FIG. 44.--Diagram of the method
+  introduced by Dr Guy and the author for giving Nitrous Oxide
+  and Oxygen, with or without Ethyl Chloride.]
+
+This inhaler, of course, will serve admirably for giving ethyl chloride
+without gas, and the author habitually uses it for giving the drug by
+the “vapour” method.
+
+In 1911, Dr Guy and the present author modified the method so as to
+permit the use of oxygen with the nitrous oxide. The inhaler which
+they then introduced serves also for nitrous oxide and oxygen, unaided
+by ethyl chloride, and the author has by its means given gas-oxygen
+to a considerable number of major surgical cases. He now, however,
+limits its use to short anæsthesias, and uses a sight-feed or a Clarke
+apparatus for long cases.
+
+  [Illustration: FIG. 45.--The Guy-Ross Inhaler for
+  Nitrous Oxide and Oxygen, with or without Ethyl Chloride.]
+
+In Fig. 44 will be found a diagram showing the method by which the
+oxygen is introduced. The 1-gallon oxygen bag is either attached
+directly to a cylinder, or suspended on an upright as shown in Fig.
+45. In either case, the bag is, before the administration, moderately
+filled with oxygen: one bagful will suffice for a short anæsthesia, and
+the supply of the oxygen from the cylinder is therefore turned off at
+once. For long cases, of course, a small trickle of oxygen into the bag
+is required to replace the gas used.
+
+In the outlet pipe from the oxygen bag is placed a ball syringe of 2
+ounces capacity. A valve in the pipe obliges the flow of oxygen to take
+place in one direction only when the bulb is squeezed, viz. from oxygen
+bag to inhaler.
+
+The remainder of the apparatus is identical with Guy’s original
+inhaler, except that the bag is of 2-gallon capacity, and is perforated
+at its base by a =Y=-tube, one limb of the fork bringing in the
+nitrous oxide, the other the oxygen.
+
+
+                            Method of Use.
+
+A few breaths of pure nitrous oxide gas are usually allowed “on the
+valve.” Rebreathing is then instituted, and the addition of oxygen
+begun. The amount required to each type of patient can only be learnt
+with experience, but the average is one full compression of the bulb
+every ten seconds. If anæsthesia is not complete at the end of one
+minute, put the indicator to “valves” again, and allow the patient
+nearly to empty the bag. Then push back the indicator to “no valves,”
+and refill the bag with nitrous oxide by opening the cylinder with the
+foot key. Some four to six compressions of the bulb are made while the
+nitrous oxide is running in. The time will now have come to add the
+dose of ethyl chloride if it be judged necessary at all. This will have
+been placed in the vial before the administration is begun. After
+emptying the ethyl chloride into the bag of the inhaler, anæsthesia
+should be complete in twenty-five seconds.
+
+The same small doses of ethyl chloride are used as is the case with
+Guy’s original method.
+
+After a little practice under supervision, students at the Dental
+Hospital learn to use this method safely and well. No example of risk
+to life has arisen after eight years’ daily experience.[11]
+
+
+
+
+                             CHAPTER XIV.
+
+                   MIXTURE OF CHLOROFORM AND ETHER.
+
+
+The mere addition of ether does not remove all the undesirable features
+of chloroform anæsthesia. A heart poisoned by excess of CHCl_{3} does
+not respond to ether stimulation. Nevertheless, CE mixtures of varying
+proportions have great value. The less lethal drug takes on part of the
+work of the more dangerous one; it also keeps the respiratory centre
+active. Viewing mixtures as dilute chloroform, it is also obvious that
+there will be with them a greater margin of error in dosage, than with
+the pure drug.
+
+Some chemical change takes place when the two drugs are mixed, for heat
+is evolved; of the nature of this change we are ignorant.
+
+The first mixture introduced was known as ACE, and consisted of one
+part absolute alcohol, two parts chloroform, and three parts ether.
+Alcohol evaporates very slowly and if it be introduced at all it should
+be in much smaller proportion. Schäfer’s mixture is one part alcohol to
+nine parts chloroform. Neither of these mixtures is now much used. The
+most useful combination is two parts chloroform and three parts ether,
+and is known as C_{2}E_{3}. In special cases, one part of chloroform to
+two parts ether may be better.
+
+
+                               Methods.
+
+_Cones_ of varying type were at first extensively used for
+mixtures. The best known is Rendle’s (Fig. 46). It is made of
+celluloid, and is perforated at the top by a series of small holes
+through which the anæsthetic is introduced. A sponge is packed into
+the upper part of the cone, and a flannelette cover completes the
+appliance. The objection to the use of this and kindred cones is that
+since chloroform evaporates more slowly than ether, the more dangerous
+drug is apt to collect in the sponge, completely altering the strength
+of the vapour after a time. This fault is remedied to a large extent by
+the open drop method now used.
+
+  [Illustration: FIG. 46.--Rendle’s Cone.]
+
+
+                        The Open (Drop) Method.
+
+For this the mask and ether dropper of Bellamy Gardner are admirably
+suited (Fig. 27). A material less close than the gauze advocated for
+open-ether is required. One layer of flannelette does very well, or
+the cheap cotton towels which used to be known in Edinburgh as “penny
+towels” in the pre-war period. The mask should fit the face with
+reasonable accuracy: there is no reason why a gauze ring should not be
+used to ensure this if the administrator is careful to adhere strictly
+to a “drop” method.
+
+The bottle into which the dropper is inserted should be of different
+_colour_ to those in which pure ether is habitually carried. This is a
+greater safeguard against a dangerous forgetfulness than a mere label.
+
+As already said, the anæsthetic must be given by a strict “drop”
+method. “Douching” at frequent intervals gives results far inferior.
+
+THE TYPE OF ANÆSTHESIA is a compromise between that of chloroform
+and open-ether. Respirations and colour are better than with pure
+chloroform, not so good as with open-ether. The size of the pupil is
+also intermediate.
+
+SCOPE.--As elsewhere explained there are many patients to whom
+open-ether cannot well be given; the greatest number of these can take
+a mixture perfectly and C.E. should certainly be chosen in preference
+to pure chloroform when possible. For refractory cases, it serves
+admirably as the inducing agent before the use of open-ether.
+
+
+
+
+                              CHAPTER XV.
+
+                              SEQUENCES.
+
+
+By a sequence we mean a method in which anæsthesia is partially or
+wholly induced by one anæsthetic or one method, and maintained by
+another. The methods mentioned in Chapter XIII. as devised
+by Dr Guy for dental purposes are examples which have already been
+sufficiently described.
+
+
+                     C.E. Mixture--Ether Sequence.
+
+Of the method of inducing anæsthesia by _C.E._, and turning later to
+_open-ether_, we have also already spoken. One thing remains to be
+said in this connection. Learn to judge the appearance of the type of
+patient who will require this alternative to open-ether induction, and
+use the sequence to such patients from the beginning. Don’t start off
+with open-ether, and find out in a few minutes that the patient is too
+obstreperous. A change from mixture to ether is harmless, the reverse
+process needs much care.
+
+The sequence of _C.E. to closed ether_ was advocated by Hewitt as a
+means of dealing with very alcoholic men, and for this purpose has
+great merits. The mixture is given until the stage of struggling is
+just about to commence, a point which experience enables one to fix
+with considerable accuracy. The remainder of the induction is conducted
+by a closed-ether inhaler, either the Hewitt wide-bore or preferably
+the Ormsby. The ether indicator which stands at about one when the
+inhaler is first applied, may be advanced very rapidly full ether
+strength being attained within a minute or two. As soon as rebreathing
+is begun with either of these instruments, it is very striking to watch
+the rapid and apparently safe subsidence into anæsthesia of the most
+troublesome patient. The struggling is cut short and greatly minimised
+in violence, and a stage which under CHCl_{3} might have presented some
+considerable risk of secondary syncope, is thus eliminated.
+
+
+                  Nitrous Oxide and Ether Sequences.
+
+This is a method greatly superior to the induction by closed-ether
+described on p. 79. Instead of the 1-gallon bag of the Clover or Hewitt
+instrument, the valve piece and 2-gallon bag of a gas apparatus are
+attached to the head of the ether inhaler (Fig. 23, on page 77).
+
+Once the gas bag is inflated from the cylinder, the supply of gas may
+be cut off. A few breaths of gas “upon the valves” are given, until the
+bag is half empty; the valve tap is then pushed over to “no valves” and
+rebreathing begun. Ether may be turned on a few seconds later, and the
+strength of the vapour may be increased more rapidly. Three-quarter
+strength of ether may be attained as a rule in ninety seconds. There is
+very little likelihood of struggling in this method.
+
+
+                       Ethyl Chloride and Ether.
+
+This is a valuable method for short operations, being easily portable,
+speedy and safe in action, and fairly agreeable to the patient. Some
+anæsthetists use this induction method as a prelude to open-ether.
+
+The Clover (or Hewitt wide-bore) instrument is interposed between the
+face-piece and the T. of the ethyl chloride inhaler, as shown in Fig.
+47. A small dose of ethyl chloride only is requisite; for an adult, 3
+c.c. is enough. This is vapourised over hot water in the usual way; a
+very light anæsthesia is induced in some sixty seconds, and the ether
+can then be turned on at a much quicker rate than if the induction be
+conducted by that drug alone.
+
+
+                                Scope.
+
+The gas-ether and ethyl chloride-ether sequences are most useful
+methods. They are quick, safe, and powerful.
+
+  [Illustration: FIG. 47.--Clover’s Inhaler adapted
+  for the Ethyl Chloride-Ether sequence.]
+
+Either may be used as “single dose” anæsthetic, the ether being pushed
+quickly up to “full” and the inhaler then withdrawn. If, however, no
+access to the mouth is required by the surgeon, ether anæsthesia may,
+by occasional breaths of fresh air be prolonged for as long as desired.
+
+
+
+
+                             CHAPTER XVI.
+
+                     THE ACCIDENTS OF ANÆSTHESIA.
+
+
+The minor difficulties of anæsthesia have already been dealt with,
+and if the instructions already given, particularly in Chapter
+III., are faithfully carried out, incidents of real danger
+will rarely occur. The soundest knowledge and the most conscientious
+care will, however, never entirely rid anæsthesia of an element of
+danger to life. The conditions now to be considered are:--
+
+   (_A_) Vomiting.
+
+   (_B_) Failure of respiration.
+
+   (_C_) Failure of circulation.
+
+
+                             (A) Vomiting.
+
+This always exposes an unconscious patient to the danger of inhaling
+solid or fluid material into the larynx, with resulting asphyxia. If
+the patient be tided through that immediate difficulty, he is liable to
+develop an inhalational pneumonia subsequently.
+
+A healthy patient properly prepared should not vomit during the
+induction stage, nor during the progress of the operation. If he
+does, it means that the induction has been too slow, or that the
+administration has been intermittent, and the patient has been
+permitted to come to too light a level of anæsthesia during the
+operation.
+
+During emergency operations where the patient’s stomach may be full of
+food, the case is different. Such patients commonly vomit early in the
+induction stage, and no skill can avert the incident.
+
+A patient suffering from intestinal obstruction, or from generalised
+peritonitis has his stomach and intestines full of highly infective
+fluid. Reverse peristaltic may set in merely as the result of the
+inhalation, or later from handling the contents of the abdomen, and
+the feculent fluid gushes up the œsophagus with little or no warning.
+Since vomiting in these cases may occur even in deep anæsthesia, when
+the cough reflex which is the normal sentry to the entrance of the
+larynx, is abolished, the dangers of insufflation are very real indeed.
+Personally, the author prefers to wash out the stomach before beginning
+to induce anæsthesia in these cases, but some surgeons believe that the
+shock of this procedure outweighs the advantages.
+
+
+                  SYMPTOMS AND TREATMENT OF VOMITING.
+
+In ordinary cases, vomiting is usually heralded by a definite train of
+symptoms. Respiration becomes shallow, the colour a little pale and the
+pulse rather small. The pupil dilates, but remains active to light,
+indicating that the alteration of respiration and circulation is not
+due to overdose.
+
+At the first appearance of such symptoms, a brisk rub of the lips and
+thereafter an increase of the vapour strength of the anæsthetic will
+often avert the impending vomiting by deepening the anæsthesia, but if
+the possibility of this complication has occurred to the anæsthetist
+too late for its prevention, the head must be turned well to one side,
+and the other shoulder slightly elevated by a pillow, so that vomited
+material will fall out of the mouth at once. When the actual act of
+vomiting is over, no time must be lost in mopping out the mouth and
+pressing on with the production of a deeper anæsthesia.
+
+
+                       (B) Respiratory Dangers.
+
+These divide themselves into two groups:--
+
+   (1) MECHANICAL.--The respiratory movements continue, but the
+   ingress and egress of air is blocked.
+
+_The symptoms and preventative treatment_ have been referred to at some
+length in Chapter III., and no further account of these is therefore
+necessary. _The treatment of a complete blockage_ of the air passages
+which resist the measure there described, alone remain to be mentioned.
+Of these, the only two effective are _artificial respiration and
+tracheotomy_ (or laryngotomy if preferred by the surgeon). Forcible
+artificial respiration by the Sylvester method, with the mouth gagged
+open and the tongue held forward by the tongue forceps, is frequently
+successful in getting over even a complete block, but the last resort
+of opening the air passage by the knife must not be delayed until too
+late. In deciding such a point, considerable judgment is of course
+called for.
+
+
+               (2) NON-MECHANICAL.--Respiratory arrest.
+
+This is usually seen in conjunction with a serious failure of the
+circulation caused by over-dosage. Exceptionally, some act of the
+surgeon sets up a reflex inhibition of the respiratory centre; the
+circulation is at the same time depressed, but to a varying degree.
+The cardinal _symptom_ is arrest of all respiratory effort. The
+_treatment_ is best dealt with under the heading of circulatory
+failure.
+
+
+                 (C) Circulatory Failure, or Syncope.
+
+By the term syncope, we mean a more or less sudden failure of the
+cardiac pump, as opposed to the form of circulatory failure seen in
+surgical shock, where the condition is chiefly, though not wholly, one
+of vaso-motor paralysis (_see_ Chapter II.).
+
+Syncope occurs under varying conditions which may for descriptive
+purposes be divided into four classes. It is not, however, always
+possible to decide with certainty into which class an individual case
+should be placed.
+
+The _symptoms_ common to all classes of syncope are:--
+
+   (1) Pallor, and loss of all tone in the muscles, noticeably
+   those of expression. The pulse is weak or imperceptible.
+
+   (2) Cessation of respiration.
+
+   (3) Dilatation of the pupil, which ceases to react to light.
+
+The four classes above mentioned are as follows:--
+
+
+                          A. PRIMARY SYNCOPE.
+
+This is peculiar to chloroform. With no other anæsthetic is it seen, at
+any rate in the healthy subject. It arises during the induction period,
+and is not necessarily preceded by any respiratory difficulty. There is
+one big inspiratory gasp, sudden and extreme pallor, and the pupil goes
+out to the rim in a few seconds. The only reasonable explanation of
+such an incident is the occurrence of vagal inhibition (_see_ page
+112). Its prevention therefore is a matter of the avoidance of a high
+percentage of chloroform.
+
+
+                         B. SECONDARY SYNCOPE.
+
+This term is applied to a collapse arising as a secondary result of
+embarrassed respiration. Though not peculiar to chloroform, it is
+far more common with that drug than with any other (ethyl chloride
+excepted). The most common time for the accident is towards the end
+of the induction period. The patient has probably been struggling,
+has clenched the jaws, and developed “mechanical” asphyxia. Violent
+inspiratory efforts are still being made, and considerable cyanosis
+develops. Either at the very moment when the respiratory difficulty
+is overcome, or while it still persists, the colour suddenly alters
+from blue to white, and the other symptoms of syncope rapidly appear.
+The exact period required to transform a blue struggling patient with
+heaving chest, into one with pallid face, and motionless chest and
+limbs, varies greatly, for reasons furnished below.
+
+The most reasonable explanation offered of such an accident is that
+given by Leonard Hill. The attempts to inspire through an air way
+mechanically blocked cause an immense strain upon the heart muscle. The
+flow of blood in the lung capillary is hindered, and the right side of
+the heart becomes over distended with blood. Its musculature is further
+damaged by the fact that the blood in the coronary vessels is deficient
+in oxygen, and that a considerable dose of anæsthetic has already been
+absorbed. There is the further fact, not mentioned by Hill, that during
+the whole period of asphyxia the peripheral resistance is rising from
+vaso-constriction. Under circumstances such as these, it is obvious
+that _any_ heart must ultimately succumb, _no matter what anæsthetic is
+in use_. It is also obvious that with chloroform and ethyl chloride,
+which are themselves heart poisons, secondary syncope will happen much
+more readily than with ether or nitrous oxide, which are not; and that
+a heart with diseased musculature will fail quicker than a healthy
+organ.
+
+Secondary syncope is almost certainly the commonest fatal accident of
+anæsthesia. The reason why this fact is not more widely recognised
+arises from the natural instinct of any one who has suffered the misery
+and ignominy of causing a death under an anæsthetic, to attribute it
+to some cause beyond human control. The _essential_ cause of secondary
+syncope is failure to maintain a free air way, which cannot be styled
+unavoidable. Two consolations may, however, honestly be offered to the
+person who has acted as anæsthetist in a case of secondary syncope.
+Firstly, it is, in certain types of cases, very difficult indeed to
+maintain a free air way; and secondly, a heart with muscle degenerated
+from fatty or other changes, may give out after very little respiratory
+embarrassment.
+
+
+                        SYNCOPE FROM OVERDOSE.
+
+This is a more gradual affair than the two foregoing; and has been
+sufficiently dealt with in the chapter devoted to the Stages of
+Anæsthesia (see p. 36).
+
+
+                          C. REFLEX SYNCOPE.
+
+Exceptionally, a patient not overdosed with anæsthetic, and not
+suffering from any mechanical obstruction to respiration, has a sudden
+attack of syncope during the progress of the operation. We here exclude
+patients who are suffering from surgical shock; the condition arises
+too rapidly for such an explanation to be accepted. Much speculation
+has been expended upon these cases. One view is that some procedure of
+the surgeon has set up a reflex inhibition of the heart through the
+vagus; another, that the reflex has taken the form of sudden vasomotor
+paresis. Levy would ascribe the condition to cardiac fibrillation.
+It may well be that all cases cannot be met by one explanation. The
+older surgeons stoutly maintained that reflex syncope could not arise
+if the patient were properly under, and that it was in the practice
+of those anæsthetists who were afraid of pushing the anæsthetic
+sufficiently, that such accidents occurred. The author’s own belief
+is that a _very_ light chloroform anæsthesia does pre-dispose to
+this accident, but that it may occur also at a deep, the very deepest
+possible level. With an anæsthetic other than chloroform, it is
+extremely rare--perhaps unknown.
+
+
+                         Treatment of Syncope.
+
+This must be speedy to be of any avail. The following are the points
+upon which to concentrate:--
+
+   (1) _Withdraw the anæsthetic._
+
+   (2) Make sure that the _air way is free_.
+
+   (3) Begin _artificial respiration_ by Sylvester’s method, the
+   movement of _expiration_ being first performed (_see_ Fig. 48).
+
+   (4) _Lowering of the head and shoulders_ is usually to be
+   recommended. It is best done by tilting the whole table as if
+   for the Trendelenberg position.
+
+   The lowering of the head attracts more blood to the carotid
+   artery and raises the blood pressure of the main vessel and
+   its cerebral branches (_see_ Fig. 35). It must, however, be
+   remembered that it will also tend to empty the blood in the
+   veins of the lower extremities and abdomen into the right side
+   of the heart, and cases in which marked cyanosis has preceded
+   pallor, are probably suffering already from engorgement and
+   dilatation of the right heart. The tilting of the table should
+   in such cases be very moderate in degree, and should not be
+   persisted in if it seems to do no good. In no case, indeed,
+   should the tilting be extreme. An angle of more than 15 or 20
+   degrees is as likely to do harm as good.
+
+  [Illustration: FIG. 48A.--Artificial respiration by
+  Sylvester’s method. Expiration.]
+
+   (5) Hot cloths may be placed over the precordial region, care
+   being taken not to burn the skin.
+
+   (6) The only _drugs_ likely to be of any avail are atropine and
+   strychnine, the former being used with the idea of paralysing
+   the terminations of the vagus in the heart muscle, the latter as
+   a cardiac tonic and a stimulant to the respiratory centre. Some
+   authorities have recommended the injection of atropine by a long
+   needle passed into the heart muscle, but most are content to
+   give either or both drugs hypodermically. Really to paralyse the
+   vagus, a very large dose of atropine is required--about ¹⁄₃₀ gr.
+   Strychnine should be given in a dose of ¹⁄₄₀–¹⁄₃₀ gr.
+
+  [Illustration: FIG. 48B.--Artificial respiration by
+  Sylvester’s method. Inspiration.]
+
+   (7) In cases where the right heart has certainly been
+   over-distended, the expedient of venesection has been tried.
+   Some six ounces may be withdrawn from the external jugular or
+   one of the veins of the arm.
+
+   (8) As a last resort, _the heart may be massaged_. The only
+   practicable route is to open the abdomen (if not already done)
+   pass one hand under the left side of the vault of the diaphragm,
+   placing the other hand over the precordial region. Between the
+   two hands, the heart can first be thoroughly compressed to empty
+   its presumably flaccid and over-distended cavities, and then
+   lightly massaged. Several cases of recovery from this measure
+   are on record.
+
+
+                          Status Lymphaticus.
+
+Before leaving the subject of accidents it may be well to allude
+to this condition, which is also known as status thymicus, and as
+lymphatism.
+
+It is met with mostly in the young, the commonest ages probably being
+five to fifteen years. Certain pathological conditions have been found
+in fatal cases, of which the most important are an enlargement of the
+thymus gland, of various lymph glands, and of the tonsils, including
+the naso-pharyngeal tonsil (adenoids). The heart muscle is frequently
+degenerated. Of the cause of these abnormalities we are as yet in
+doubt. There is some reason to believe that the condition tends to
+disappear with advancing years, if the subject survive.
+
+The most outstanding clinical fact in connection with the disease
+is its tendency to cause sudden death on very little provocation. A
+fright, a sudden exertion, and above all an anæsthetic may cause sudden
+and fatal syncope.
+
+
+                              DIAGNOSIS.
+
+Suspicion that the disease is present may be aroused in several ways.
+The presence of enlarged tonsils and adenoids, combined with general
+enlargement of lymph glands from no obvious cause, and a tendency
+to faint, make a very suggestive picture. “Night-crowing” (a sudden
+attack of laryngeal spasm, occurring at night, and often repeated
+at intervals) also raises grave doubt. The diagnosis can only be
+established with certainty by an X-ray photograph, when the great
+enlargement of the thymus may be seen in the upper part of the chest.
+
+
+                  ANÆSTHETICS IN STATUS LYMPHATICUS.
+
+Too frequently the condition has never been suspected, and a fatality
+occurs from sudden syncope, usually during the induction period, but
+occasionally during the progress of the operation. It would, however,
+be fallacious to suppose that an anæsthetic is necessarily fatal even
+to an undoubted case. If the drug (preferably ether) be given with
+great care, and the operation done carefully at a level of anæsthesia
+neither too light nor too deep, there is every reason to believe that
+the danger can be, and often is, successfully averted.
+
+At the same time, it must be understood that in a known case, operation
+should always be avoided or deferred if possible.
+
+
+
+
+                             CHAPTER XVII.
+
+                      THE SEQUELÆ OF ANÆSTHESIA.
+
+
+                          Respiratory System.
+
+After operations performed under any form of anæsthesia, even spinal,
+there is always a possibility of pneumonia or bronchitis. The
+anæsthetic itself is not always to blame. The patient has suffered
+trauma and is confined to bed, and may develop a hypostatic pneumonia
+just as a person who has suffered from a fractured thigh so commonly
+does, even though he has had no anæsthetic at all.
+
+It is probable that organisms, capable under certain circumstances of
+causing inflammatory disease of the respiratory tract, are present
+in a large proportion of apparently healthy people. Pneumococci and
+streptococci of varying strains may be grown from nasal or pharyngeal
+secretions of patients who suffer from catarrh of these regions, and
+may reappear upon slight provocation even when prolonged treatment had
+apparently banished them permanently. All that is required to start
+an acute infection of lungs or bronchi, is some factor that depresses
+vitality and lowers body resistance to the organism. And if in addition
+use has been made of an inhalational anæsthetic such as ether, which
+may cause an immediate and fairly acute congestion of the respiratory
+mucous membranes, it is not to be wondered at that serious sequelæ
+follow in a certain proportion of cases.
+
+Laboratory results go to show that ether lowers the opsonic index
+of the blood to pneumococci and streptococci, but without placing
+undue emphasis upon a mere isolated phenomenon such as that, it is
+plain that the whole conditions of the patient after operation are
+favourable to the occurrence of pneumonia or bronchitis, and that of
+all anæsthetics ether is the most likely to be the determining factor.
+
+Experience gained during the war has thrown a certain amount of light
+upon this subject. Post-anæsthetic bronchitis and pneumonia was
+very prevalent among the wounded, far more so than among civilian
+patients. It is, the author believes, reasonable to attribute this
+fact to several causes. In the first place, the soldier’s life,
+alternating between stuffy billets and wet trenches, predisposed him
+to naso-pharyngeal catarrh of a fairly high degree of infectivity.
+Enthusiastic press representatives might state that you could not take
+cold so long as your feet and legs were always buried in half frozen
+mud, but experience hardly bore out their golden promises. Again, the
+soldier did not improve his catarrh by inveterate cigarette smoking.
+Lastly, military hospitals were large institutions, some under canvas,
+some in huts, some in buildings constructed for other purposes, and
+rapidly altered to the urgent needs of the army. Of whatever type,
+nearly all had one feature in common--many of the surgical wards were a
+long (and draughty) way from the operating theatre.
+
+For the prevention of post-anæsthetic pneumonia, the author offers the
+following tentative suggestions:--
+
+   (1) See that the skin is kept covered up as much as possible
+   during the operation and that the patient is not exposed to
+   draughts during or after it. Rooms can, and should be, well
+   ventilated without cold draughts.
+
+   (2) If a patient has an acute or sub-acute naso-pharyngeal
+   catarrh, treat it as fully as possible before operation by
+   sprays and gargles.
+
+   (3) Do not use ether to patients who suffer or recently have
+   suffered from such conditions.
+
+   (4) Give a hypodermic of morphia and atropine before operation
+   as a routine.
+
+   (5) In so far as possible, let the patient’s shoulders and head
+   be raised by pillows during the early hours of convalescence.
+
+   (6) Lastly, remember that while no care will absolutely banish
+   these dangerous sequelæ from our practice, the greater care
+   and skill shown by the anæsthetist, the less bronchitis and
+   pneumonia will appear among his patients. As regards ether, the
+   author believes that it is the strength of vapour used, more
+   than the duration of the anæsthesia, which counts. It is for
+   that, among other reasons, that he has for the induction period,
+   no hesitation in recommending a method whereby a small part of
+   the requisite ether strength is replaced by chloroform.
+
+
+                               Vomiting.
+
+After an anæsthesia lasting more than a few minutes, it may almost be
+regarded as normal for the patient to vomit once or twice. Usually this
+occurs a few minutes after the administration has ceased. In the case
+of nitrous oxide and oxygen, even this slight disturbance may not occur.
+
+The amount of vomiting which after this stage may be regarded as
+normal is difficult to determine. The author took notes of some 300
+cases on this point. The details of his results are not suitable for
+a text book, but, broadly speaking, it would appear that after an
+operation of ordinary duration and severity, the vomiting returns on
+the average some five or six times, and usually ceases on the evening
+of the operation day. A limited number continue to vomit at intervals
+until the early hours of the following morning. With nitrous oxide
+and oxygen the vomiting is far less than the above, though even with
+this anæsthetic quite severe emesis may occur. With closed-ether, the
+trouble is very violent for a short time, large quantities of mucous
+being ejected: it is probable that after the first two hours, it is no
+more marked than after open methods. The use of morphia and atropine
+before operation most certainly reduces the violence and duration of
+this sequela.
+
+Prolonged more than twenty-four hours, the condition must be regarded
+as definitely abnormal.
+
+
+                       PREVENTION AND TREATMENT.
+
+The adoption of open-ether preceded by morphia and atropine and due
+skill and thought on the part of the anæsthetist, combined with proper
+preparation of the patient, are the only means of prevention at our
+command.
+
+The raised position of the head and shoulders during the recovery
+stage undoubtedly tends to reduce the nuisance. It is a vexed question
+whether to give or to withhold fluids after operation--and this matter
+is of course in the hands of the surgeon, not the anæsthetist. In
+certain cases, the author believes that it is worth while trying the
+effect of a cup of fresh tea with very little sugar or milk. Even if
+rejected in a few moments, the astringent effect of the infusion seems
+to soothe the gastric mucous membrane, and give relief.
+
+
+                       Post-operative Acidosis.
+
+               (Synonym--Delayed Chloroform Poisoning).
+
+In a limited number of cases, post-operative emesis assumes a grave
+type, and definitely threatens life. Such cases began to be studied
+in the early part of this century, and though our knowledge of the
+condition is still incomplete, the student should be acquainted with
+the present views held upon the subject.
+
+Clinically, the earliest symptom to raise suspicion, is the
+reappearance of vomiting at a time when one would expect such trouble
+to have abated, usually twenty-four or thirty-six hours after
+operation. Within a few hours, the nature of the vomit changes from
+the usual bilious stomach contents, and shows obvious evidence of
+the presence of _altered blood_. The pulse and temperature begin to
+rise, the countenance assumes an anxious look. A trace of jaundice is
+usually present. The nervous system becomes affected as shown first in
+restlessness, and later, delirium. Every degree of this condition is
+possible, but a very large proportion of recognisable cases pass into
+coma, and death supervenes within a few days, sometimes less.
+
+Investigation into such cases has shown that the essential underlying
+condition is an acidosis closely allied to that seen in diabetic coma.
+The breath has the peculiar sweetish aroma of acetone, and acetone,
+diacetic acid, and B. oxybutyric acid successively appear in the urine.
+
+Post-mortem, the most striking change found is a profound fatty
+degeneration of the liver, the cells of which are disintegrated as in
+acute yellow atrophy.
+
+It is obvious from the foregoing that there is present a very
+remarkable abnormality of metabolism. Mr Rendle Short, in his admirable
+book, _The New Physiology in Surgical and General Practice_, gives
+the following explanation of the condition:--
+
+“The physiological process of dealing with fat is to resolve it into
+carbon di-oxide and water. If we make a pound of fat into tallow
+candles and burn it, we shall obtain carbon di-oxide and water, and a
+certain amount of heat will be evolved. If the pound of fat is eaten
+and absorbed by a man or an animal, it will be burnt to the same end
+products, and the same amount of heat will be given out. But in certain
+circumstances, an abnormal mode of breaking down is followed, and
+there are produced, first B. oxybutyric acid, then diacetic acid, and
+finally acetone. If this takes place on a large scale, the conversion
+into acetone fails to keep pace with the production of acids. Therefore
+first acetone appears in the urine, then diacetic acid, and finally
+oxybutyric acid; the last may rise rapidly to an enormous figure: 30,
+50, or even 180 grams may be passed daily.”
+
+Later in the same chapter, Short propounds the question as to what are
+the special circumstances in which the breaking down of fat deviates
+from its normal course, and follows this dangerous route. The answer
+is, he says, quite definite and decisive. When the tissues are unable
+to obtain sugar from the blood, fat is broken down _via_ these
+dangerous acids to acetone, instead of to carbon di-oxide and water.
+
+Such an inability on the part of the tissues to obtain sugar arises
+under several conditions:--
+
+   (_a_) In diabetes, where sugar though freely present in
+   the blood cannot, for some reason still not clearly known, be
+   assimilated by the tissues.
+
+   (_b_) In poisoning by salicylates.
+
+   (_c_) In starvation, for obvious reasons. The supply of sugar
+   from the liver has been used up, and the patient, living on his
+   own fats, breaks them up abnormally.
+
+   (_d_) In post-anæsthetic poisoning, for reasons which are
+   at present not clearly ascertained.
+
+Upon the theoretical side it is therefore not possible to say more than
+that anæsthetics sometimes initiate this abnormal metabolic process. To
+the question as to why and how they do so, we can as yet give no answer.
+
+Upon the practical side, we can, however, speak much more definitely.
+Acidosis follows the use of ether very rarely indeed: after nitrous
+oxide it is unknown. Chloroform has been the drug used in almost every
+recorded case, while ethyl chloride has been responsible in a few
+isolated instances. Young children are much more prone to suffer than
+adults, though the author had a fatal case in a lady well over forty
+years of age: he has also seen a case very nearly fatal in a soldier
+aged twenty. This man was, a week after recovery from acidosis,
+anæsthetised for half-an-hour with nitrous oxide and oxygen, without
+exhibiting any signs of a return of his dangerous condition. Anæsthesia
+repeated in the same subject after a short interval is more prone
+to start the process than a first inhalation. Lastly, acute sepsis,
+particularly in the young, is notorious for its liability to be
+followed by acidosis.
+
+
+                       PREVENTION AND TREATMENT.
+
+The obvious moral of the foregoing is that chloroform should not be
+administered to patients suffering from acute sepsis, particularly if
+they be very young. Indeed, so common is a mild degree of acidosis
+among children, some surgeons consider there is a definite risk in
+giving chloroform to them at all unless special precautions are taken.
+Chief among these are regular dosage for a day or two before operation,
+with considerable doses of bicarbonate of soda and sugar, which is a
+routine measure in some children’s hospitals.
+
+As regards curative treatment, much can be done if the gravity of the
+condition is recognised early. The stomach is first washed out with
+alkalis, and a substantial dose (one dram) of bicarbonate of soda left
+in it. The same dose is repeated hourly by the mouth, if retained, or
+per rectum. A useful addition to the alkaline treatment is dextrose,
+also in teaspoonful doses. In grave cases, these drugs should be given
+intravenously in saline solution.
+
+These measures combined with warmth, and ample fluids by mouth or
+rectum, will often save life, but to be of any value they must be
+begun early. Fulminating cases occur which succumb rapidly in spite of
+treatment.
+
+
+
+
+                            CHAPTER XVIII.
+
+                        POSTURE OF THE PATIENT.
+
+
+The position in which the patient is lying is of as much importance to
+the anæsthetist as to the surgeon. It is for the surgeon to say what
+he wants and for the anæsthetist to realise how his own work will be
+thereby affected.
+
+
+                          Dorsal Decubities.
+
+This is the ordinary position and calls for no extended comment. The
+pillows must be so arranged that at no spot is the body acutely flexed
+or extended. Abdomen, thorax, neck, and head must all be roughly in a
+straight line.
+
+Deep-chested subjects require a higher pillow than those with shallow
+chests, otherwise the neck is bent back and respiration obstructed.
+
+The arms should either be folded and retained by a bandage or other
+device over the chest, or extended so that the hands can be slipped
+under the buttocks and retained there by the body weight. An arm which
+is allowed to hang over the side of the table is likely to show next
+day and for many months afterwards, the condition of drop-wrist from
+musculo-spiral paralysis.
+
+
+                          Face-down Position.
+
+This is an awkward position for the anæsthetist; there being a general
+tendency to respiratory embarrassment. Put a pillow under the upper
+part of the thorax, leaving the lower part and the abdomen as free as
+possible. Let the head project from the pillow, so that the face can be
+got at without undue rotation of the neck. The intratracheal method is
+a great help.
+
+
+                           Lateral Position.
+
+This may be called for either with or without the addition of a
+sand-bag or inflatable air-pillow to push the loin upwards. In either
+case, there is a tendency for the upper shoulder to fall forwards, the
+position then assimilating itself to the face-down position. This is
+best met by a support fixed to the table, upon which the upper arm may
+be rested. Failing such a convenience, a sand-bag may be pushed in to
+keep up the shoulder, or the assistance of a nurse may be required.
+
+
+                      The Trendelenburg Position.
+
+Slight tilting of the head end of the table downwards is often useful
+in assisting the return of bowel into the abdomen: in this position,
+the patient usually takes the anæsthetic very well. It must not be
+assumed until the third stage of anæsthesia is reached.
+
+For many gynæcological operations, however, the full Trendelenburg
+position is required. Healthy subjects usually do quite well in it, but
+stout persons not uncommonly show a good deal of cyanosis. At the close
+of the operation it is essential to restore the table to the horizontal
+_slowly_: the physics of the circulation are profoundly modified,
+and if any serious degree of shock is present, rapid return to normal
+may initiate a collapse.
+
+In the full position, the weight of the body should be taken by metal
+supports attached to the table against which the shoulders may rest. To
+hang the entire weight of the body upon the legs may cause a good deal
+of after-suffering to the patient.
+
+
+               The Sitting-up Position. (_See_ Fig. 49.)
+
+The object of this position is to diminish venous engorgement and
+bleeding in operations requiring delicate dissection in the region of
+the neck. Prof. Alexis Thomson introduced the position into Edinburgh
+surgery: the author was at first rather nervous of it, but has found
+that with proper precautions the patients do uncommonly well. Beyond
+all doubt, the position is a great help to the work of the surgeon.
+
+Not every surgical table is capable of giving the full position without
+the use of many pillows and sandbags. The head-piece of the table is
+tilted up at an angle of about 75° or even 80°, and the patient pulled
+up so that the flexion of the body occurs in the lumbar, not the dorsal
+spine. A small sand-pillow is placed behind the neck so as to produce
+slight extension. Another heavier one is placed under the thighs to
+prevent the body slipping down. A slight tilt downwards towards the
+head end may be given to the table as a whole with the same object.
+
+  [Illustration: FIG. 49.--Sitting-up posture for operations
+  on the neck.]
+
+One should not in this position attempt to induce a deep chloroform
+anæsthesia. Weak C.E. mixture at most, but better simply open-ether is
+the method of choice. The induction is begun with the shoulders raised
+to a modified degree, and the full position assumed in a light third
+stage anæsthesia.
+
+Intratracheal ether combined with this position is an ideal anæsthesia
+for the removal of goitre or extensive dissections in the neck for
+enlarged glands.
+
+
+        O’Malley’s Position for Nasal Surgery. (_See_ Fig. 50).
+
+The author became acquainted with this useful position while acting as
+Anæsthetist at the Royal Herbert Hospital, Woolwich, where the Nose
+and Throat Department was under the charge of Major O’Malley, F.R.C.S.
+Major O’Malley was kind enough in a recent letter written by request to
+refresh the author’s memory of the details.
+
+  [Illustration: FIG. 50.--O’Malley’s posture for
+  intra-nasal surgery.]
+
+With the patient lying as shewn in the photograph, every part of the
+interior of the nose can be easily inspected by the surgeon; the
+elevation of the head and shoulders prevents undue bleeding, and
+such hæmorrhage as does occur goes down the gullet, where it does no
+particular harm, instead of into the larynx. The degree of flexion
+of the head upon the neck is not so extreme as to interfere with
+respiration.
+
+The details of O’Malley’s procedure are as follows:--
+
+The interior of the nasal cavities are packed with gauze soaked in
+adrenalin and novocain a quarter of an hour before operation, and the
+patient receives a very small dose of morphia and atropine immediately
+before anæsthesis is induced; given in this way it does not complicate
+the induction with chloroform to the same extent as if given earlier.
+The patient lies with the top of the head level with the top of the
+table, and the head and shoulders (including the upper two-thirds of
+the shoulder blades) supported on the usual depth of pillow. Induction
+is by chloroform or mixture; a very light third stage only is aimed
+at. When it is attained the mouth is opened by a gag, and Phillip’s
+Oral Airway inserted (_see_ Fig. 8). Strict oral respiration is
+essential to success. If air is passing in and out of the nose, blood
+is spluttered all over the surgeon, seriously interfering with the
+harmony of the proceedings. Junker’s chloroform bottle is ready, and
+the end of the supply pipe is passed into one of the side holes in the
+air way.
+
+The head of the table is now elevated to an angle of 45°, and a small
+sand pillow slipped behind the occiput. The gauze is removed from the
+nose, and the operation can be performed with great comfort.
+
+The circulation of the patient needs careful watching for the first
+minute or two after the table head has been elevated, but thereafter
+there is usually no special cause for anxiety. The area of operation
+is locally anæsthetised by the action of the novocain and a light
+chloroform sleep only is required.
+
+
+
+
+                             CHAPTER XIX.
+
+                         CHOICE OF ANÆSTHETIC.
+
+
+In considering this matter, some repetition of points to which
+reference has already been made, is inevitable. Indeed, this chapter
+may be regarded as a revision of the whole subject.
+
+Before deciding upon drug and method suitable for the individual case,
+we must consider the age and sex, the physical type and temperament,
+the possible presence of some definite pathological condition, and the
+nature and duration of the operation.
+
+In relation to this last point, we must remember that an anæsthesia
+must be adequate to the purpose of the surgeon, but that it is improper
+to incur more risk to life than is necessary. For instance, an
+abdominal section case must be fully relaxed, and if in an individual
+case, chloroform is the only drug which will give that effect, there
+need be no hesitation in using it. On the other hand, many other
+methods with a far smaller mortality rate are available if all that is
+required is the extraction of a tooth or the incision of an abscess,
+and in that group of cases, unfamiliarity with such anæsthetics as
+nitrous oxide or “ethyl chloride and ether” will not be held as a
+sufficient defence if chloroform has been given with a fatal effect.
+
+
+                           Normal Subjects.
+
+Let us take first the case of the healthy adult about to undergo a
+_major_ operation. For this, we unhesitatingly choose what we may term
+the “stock” method--open-ether preceded by morphia and atropine.
+
+If the operation be _brief_, we have a choice of methods. For the
+extraction of teeth, where access to the mouth is essential, the
+following table will help:--
+
+  +------------------------+---------------------------+-------------------------+
+  |                        |Duration of Available      |                         |
+  |ANÆSTHETIC DRUG AND     |  Anæsthesia, when         |        REMARKS.         |
+  |METHOD.                 |  given as “Single         |                         |
+  |                        |  Dose.”                   |                         |
+  +------------------------+---------------------------+-------------------------+
+  |Nitrous oxide           |30 to 40 seconds           |                         |
+  |Nitrous oxide and       |40 to 50 seconds           |                         |
+  |  oxygen                |                           |                         |
+  |Ethyl chloride          |70 to 90 seconds           |Only to be recommended   |
+  |                        |                           |  in special cases (_see_|
+  |                        |                           |  page 127).             |
+  |Gas and ethyl chloride  |70 to 90 seconds           |                         |
+  |Gas-oxygen and ethyl    |70 to 90 seconds           |                         |
+  |  chloride              |                           |                         |
+  |Gas and ether           |Anything up to 2 to 5      |May cause after vomiting.|
+  |                        |  minutes according to     |                         |
+  |                        |  duration of inhalation   |                         |
+  |Ethyl chloride and ether|Anything up to 2 to 5      |May cause after vomiting.|
+  |                        |  minutes according to     |  More portable.         |
+  |                        |  duration of inhalation   |                         |
+  |Nasal gas               |5 to 10 minutes (not a     |Requires considerable    |
+  |                        |  “single dose” anæsthetic)|  practice to give well. |
+  |Nasal gas and oxygen    |No limit                   |Easier to give than      |
+  |                        |                           |  above but apparatus    |
+  |                        |                           |  rather importable.     |
+  +------------------------+---------------------------+-------------------------+
+
+In cases where access to the mouth is not required, and where it is
+therefore unnecessary to “charge up” the patient with anæsthetic, we
+have also a choice which may be expressed tabularly:--
+
+  +------------------------+-----------------------------------------------------+
+  |      ANÆSTHETIC.       |                     REMARKS.                        |
+  +------------------------+-----------------------------------------------------+
+  |Nitrous oxide           |Apparatus simple: short administration can be        |
+  |                        |  mastered easily. A little more practice required   |
+  |                        |  for cases prolonged by admitting air. Muscles      |
+  |                        |  not relaxed, and patient may move when cut.        |
+  |                        |                                                     |
+  |Nitrous oxide and       |Apparatus more complicated, but short administrations|
+  |  oxygen                |  present no great difficulty to the beginner.       |
+  |                        |  Muscles not completely relaxed unless a little     |
+  |                        |  ether added.                                       |
+  |                        |                                                     |
+  |Gas and ether           |Quick and safe anæsthetic. Deep anæsthesia           |
+  |                        |  may be obtained if ether is “pushed.”              |
+  |                        |                                                     |
+  |Ethyl chloride and ether|The same. More portable than above.                  |
+  +------------------------+-----------------------------------------------------+
+
+In this group of short operations, special reference must be made to
+the _reduction of dislocations_. Here two important features
+require notice. The whole object of the proceeding is to relax muscles,
+and therefore nitrous oxide or gas-oxygen are unsuitable. Secondly,
+the tendency to reflex syncope just at the moment of reduction is very
+great. For this reason, chloroform has here a painfully high mortality
+rate; closed-ether, preceded by gas or ethyl chloride, is undoubtedly
+the method of choice.
+
+
+                         The Extremes of Age.
+
+Children up to the age of ten years take ether badly, salivation
+and bronchial secretion being sometimes very troublesome. Atropine
+mitigates this nuisance to a limited degree only. Chloroform is the
+best drug up to five or six years; from five to ten, mixture; after
+that, open ether.
+
+In children of any age, suffering from acute sepsis, the immediate
+annoyances and possible respiratory sequelæ of ether must be faced
+(_see_ page 156), owing to the probability of acidosis.
+
+As regards short anæsthetics in children, nitrous oxide, if given at
+all, should be freely diluted with oxygen, otherwise most undesirable
+cyanosis will occur. To children under three or four, even gas-oxygen
+is of doubtful safety. Short anæsthesias in such cases may be induced
+by open ethyl chloride, with a few drops of ether added.
+
+Old people are, unless very feeble, best anæsthetised by a mixture of
+chloroform and ether. Whatever anæsthetic be chosen, the utmost care
+must be taken to avoid cyanosis. A cylinder of oxygen should be at hand
+from which to enrich the atmosphere breathed, by trickling the gas into
+the mouth through a rubber tube, and is a great safeguard in dealing
+with the old.
+
+
+                                 Sex.
+
+On the average, women take anæsthetics much better than men, being far
+less liable to jaw clenching and other forms of mechanical asphyxia,
+and showing less excitement during the induction stage. In the female
+subject induction by open-ether requires very little assistance from
+C.E. mixture.
+
+
+          Physical Type and Temperament, and Habits of Life.
+
+Heavily built muscular men are troublesome subjects. Induction requires
+a rather strong vapour of ether: if the open method is used, there may
+be to the beginner much temptation to make use during the induction
+stage of C.E. mixture to an extent not contemplated in the description
+given of that method in chapter IX.: it is therefore wise to induce
+either with closed-ether or with C.E. mixture as described in chapter
+XV., and to change to the perhalation method only when full anæsthesia
+is attained.
+
+As regards alcoholics and excessive smokers, these are well dealt with
+by the C.E. open-ether sequence. Recourse may be made to the Ormsby
+inhaler as already explained on page 137. The reader is warned not to
+be deceived by the stout, rosy face of the typical alcoholic. He often
+looks a great deal stronger than he really is. Many such are really
+feeble subjects: although they shout and struggle no great addition
+to the usual vapour strength of anæsthetic is safe or required: what
+_is_ required, is a little extra time. Once fully under, the robust
+appearance of the patient disappears, and the fact that one is dealing
+with a rather broken constitution and a poor circulation is obvious.
+
+Reference has already been made to the fact that persons with defective
+nervous systems, neurotics, and especially epileptics, show persistence
+of some muscular movements for some time, and therefore require very
+careful watching.
+
+
+    Special Operations and Pathological Conditions in the Patient.
+
+These are of the utmost importance, but to consider each fully from
+the anæsthetic point of view, would lead us into great detail. The
+anæsthetist must acquaint himself with any abnormality present, and
+consider it carefully in the light of the general principles already
+explained. The following very brief hints for selected cases and
+operations may, however, be found useful.
+
+
+                          UPPER AIR PASSAGES.
+
+_Artificial teeth._ Must be removed before inducing.
+
+_Tongue and jaw cases._--Intratracheal ether the best--failing that,
+rectal oil ether, or Junker’s inhaler.
+
+_Nasal operations._--If adrenalin is to be used, it must precede,
+not follow, chloroform--many fatalities have occurred from injecting
+or even packing with adrenalin in light chloroform narcosis. Some
+surgeons object to ether because of the bleeding, but this can be
+largely remedied by raising the head and shoulders, and by packing with
+adrenalin. Many surgeons prefer local to general anæsthesia.
+
+_Nasal insufficiency._--Don’t allow a patient to continue to make
+ineffectual attempts to breathe through a narrow nose. Establish mouth
+breathing, or use Silk’s tubes (_see_ Fig. 9).
+
+_Tonsils and adenoids._--Give ethyl chloride by the vapour method.
+
+_Tumours and inflammatory swellings obstructing respiration._--
+Don’t use closed methods. Have tracheotomy instruments at hand, and a
+cylinder of oxygen.
+
+_Gôitres, especially exophthalmic gôitre._--Don’t use chloroform: it
+has caused many fatalities; morph-atropine, followed by open-ether is
+the safest. In bad cases, use rectal oil ether if intratracheal is not
+available. The “sitting up posture” is a great help (_see_ page 168).
+Use anoci-association if surgeon is willing.
+
+
+                                CHEST.
+
+_Bronchitis and pneumonia_ (_see_ remarks in chapter XVII).
+
+_Emphysema and rigid chest wall._--Patients take anæsthetics badly;
+they cyanose quickly, the abdominal wall cannot be made either lax or
+quiet, since the patient’s natural method of respiration is abdominal
+rather than thoracic. Lastly, there is frequently a dilated heart with
+degenerate cardiac muscle, giving an abnormal tendency to secondary
+syncope. Give a trickle of oxygen through a tube from a cylinder: don’t
+be tempted to overdose with anæsthetic in the vain hope of securing
+ideal relaxation of the abdominal wall.
+
+_Empyæma._--Be careful: a good many accidents have happened. Use
+chloroform with added oxygen: aim at an anæsthesia just deep enough
+to prevent straining which might rupture the empyæma into the lung
+and drown him in his own pus. Withdraw the anæsthetic as soon as the
+abscess is opened.
+
+_Phthisis._--Don’t use closed-ether: it may start
+hæmorrhage--open-ether rarely does any harm unless the condition is
+very acute.
+
+
+                          CIRCULATORY SYSTEM.
+
+_High tension, arterio-sclerosis, and aneurysm._--Avoid pure
+nitrous oxide: in severe cases, C.E. mixture and oxygen is the safest.
+
+_Heart._--Well compensated cases of _valvular disease_
+take chloroform or open-ether well, provided a free air-way is
+maintained. Closed methods should be avoided. Cases of _myocardial
+disease_ with dilated cavities present special dangers. Open-ether
+with added oxygen meets the case better than any other anæsthetic.
+_Pericarditis_, both acute and chronic, has been found as the
+determining factor in many anæsthetic fatalities.
+
+
+                       ACUTE INFECTIOUS DISEASE.
+
+_Febrile patients_ absorb anæsthetics very rapidly and therefore
+go under very quickly. Acute septic cases must not have chloroform
+or ethyl chloride (_see_ page 155): nitrous oxide and oxygen is
+ideal, ether the next best. Patients who have suffered from acute
+infectious disease, especially diphtheria and influenza, may present
+some weakness of heart muscle for many months after the attack.
+
+
+                     EXHAUSTED AND SHOCKED CASES.
+
+Give nitrous oxide and oxygen if possible--failing that, ether.
+Closed-ether sometimes does very well for the induction stage.
+
+
+                               DIABETES.
+
+Chloroform is wholly inadmissible.
+
+
+                        GENITO-URINARY SYSTEM.
+
+_Kidneys._--Avoid ether in acute or sub-acute nephritis: give it,
+however, for nephrectomy when the other kidney is sound.
+
+_Bladder._--Distending the bladder with lotion often causes reflex
+inhibition of respiration: if that happens, stop the anæsthetic, give
+artificial respiration, and ask the surgeon to get on with opening the
+bladder. _Morphia_ usually arrests temporarily the secretion of urine:
+it should therefore not be given if chromocystoscopy or catheterisation
+of the ureters is contemplated.
+
+_Prostatectomy cases_ are often rather broken subjects: give a fairly
+deep anæsthesia until the shelling out of the prostate is begun: then
+be careful--the patient is breathing deeply as a rule, and can readily
+get an overdose. He will inevitably suffer a fair amount of shock:
+be ready to lower the table at the head end if any serious collapse
+occurs. Don’t be shy of starting a little artificial respiration even
+though the natural function is not entirely abolished.
+
+_Circumcision_ usually causes a good deal of laryngeal spasm,
+especially in children. Don’t try to abolish this by deepening the
+anæsthesia. You won’t succeed unless you nearly kill the patient. Rub
+the lips, and if very severe ask the surgeon to stop a minute until the
+crowing becomes less.
+
+_Castration._--Always give ether, or gas-oxygen. Castration and
+reduction of dislocation are the two commonest causes of reflex syncope
+under chloroform.
+
+
+                 MENSTRUATION, PREGNANCY, AND LABOUR.
+
+It is usual to avoid anæsthetics during the menstrual period if
+possible, the nervous system being unlikely to be at its best at that
+time.
+
+Pregnant patients take no harm from an anæsthetic properly given,
+but undue cyanosis must be avoided or abortion may occur. The pains
+of labour may be alleviated by chloroform given to an early second
+stage only, or by “twilight sleep” (_see_ page 44). For the major
+operations of obstetrics, however, ether has its usual advantages,
+provided no bronchitis be present. The shock of such operations as a
+difficult version is considerable, and quite sufficient to call for
+ether rather than chloroform.
+
+   _Indication for Local and Spinal Anæsthesia._--The foregoing has
+   been written in reference to inhalational anæsthesia solely. Mr
+   Wood has indicated in chapters XX. and XXI. the class of case in
+   which the methods he describes are to be preferred.
+
+
+
+
+                              CHAPTER XX.
+
+                           LOCAL ANÆSTHESIA.
+
+
+By the term local anæsthesia, or more correctly _local analgesia_,
+is meant the loss of sensibility to painful stimuli without loss of
+general consciousness. It may be induced in a considerable number
+of ways, but for practical purposes there are only four methods of
+value:--(1) by infiltration of the tissues to be operated upon by a
+solution of the drug, (2) by injecting the solution into or around
+the nerve trunks supplying the part, (3) by painting the solution on
+a mucous surface, and (4) by the application of intense cold. The
+last method has only a limited application. The method of injecting
+the anæsthetic into the blood vessels of the part is still in the
+experimental stage and is not to be recommended for general use.
+
+It is advisable first to consider the behaviour of the principal drugs
+which are employed.
+
+
+                               Cocaine.
+
+This was the first drug to be widely used for the production of
+local anæsthesia. It is an alkaloid occurring in the leaves of
+_Erythroxylon Coca_. It is only slightly soluble in water--about
+1 in 1300, but the hydrochloride of cocaine is freely soluble, and it
+is this salt that is commonly used for aqueous solutions. The solutions
+do not keep well, and should be made up shortly before being used. The
+drug is decomposed by boiling.
+
+ACTION.--When a solution of cocaine is injected into the tissues,
+the sensory nerve endings become anæsthetic over the area into which
+the drug penetrates, direct paralysis of the nerve terminals being
+produced. When it is injected into or around a nerve trunk it blocks
+the transmission of nerve impulses. When it is applied locally to a
+mucous membrane, it produces, besides a loss of sensation, a feeling
+of constriction and a distinct pallor and contraction of the vessels,
+which point to a local action on the vessel walls. The drug is very
+frequently applied to the eye. There it produces not only local
+anæsthesia, but also contraction of the conjunctival vessels, and this
+is followed by dilatation of the pupil and often by partial loss of the
+power of accommodation.
+
+COCAINE POISONING.--Certain patients show an idiosyncrasy to the
+action of cocaine, and the greatest care must be exercised in its use.
+Absorption of small quantities usually causes mental excitement. The
+patient becomes restless and garrulous, and a feeling of happiness
+may be produced, but in other cases the patient becomes anxious
+and confused. In some patients a small dose is followed by a calm
+languorous state, resembling that produced by morphia, but with less
+tendency to sleep. The pulse is accelerated, the respiration is quick
+and deep, and the pupils are dilated. When poisonous doses have been
+administered, the heart becomes extremely accelerated, powerful tonic
+or clonic convulsions supervene, the breathing becomes rapid and
+shallow, and may be finally arrested during a convulsion. In some
+cases a different set of symptoms are observed, fainting and collapse
+occur, and convulsive seizures are almost entirely absent. The heart
+is slow and and weak, the respirations are slow and shallow, the skin
+is cyanotic and cold, and death takes place from gradual arrest of
+respiration.
+
+TREATMENT.--The treatment consists in endeavouring to encourage the
+action of the heart by every possible means. The patient is placed
+flat on his back, if he is not already in this position, hypodermic
+injections of ether and strychnine are administered, and hot coffee
+given by the mouth; warmth is of great importance. Artificial
+respiration is commenced if respiration begins to fail. There is no
+specific antidote to cocaine.
+
+DOSAGE.--The maximum dose of cocaine that can be given with safety is
+¾ of a grain. The amount of solution that may be employed depends
+upon the strength. To make a 1 per cent solution, 1 gr. of cocaine
+hydrochloride is dissolved in 110 minims of distilled water or half
+strength normal saline; from these proportions the amount of cocaine
+in a given solution can be calculated. It will be seen that the amount
+of cocaine solution, even with strengths as weak as ½ or ¼ per cent,
+that can be used with safety is small and insufficient to anæsthetise
+an area of any great extent. Owing to its toxicity cocaine has largely
+fallen out of use for the production of infiltration or regional
+anæsthesia, though it is still widely used in ophthalmic surgery and in
+the surgery of the ear, nose and throat.
+
+
+                              Novocaine.
+
+This drug is immensely superior to cocaine for ordinary surgical
+purposes. It is the hydrochloride of a synthetic base, its chemical
+formula being C_{13}H_{20}N_{2}O_{2}, HCl. It is soluble in water 1
+in 1, and can be heated to 120°C without decomposition. Its solutions
+possess slight antiseptic properties, and are capable of repeated
+boiling without affecting their strength. They may be kept for several
+months without suffering any change in their action, a quality not
+possessed by any other anæsthetic agent.
+
+The _toxicity_ of novocaine is one-fifth or one-seventh of that of
+cocaine. When used in conjunction with adrenalin, its anæsthetic
+activity is equal to that of cocaine. When injected into the tissues
+it produces no irritant effects like certain other local anæsthetics,
+notably stovaine. For the production of local anæsthesia it is used in
+½ per cent. solution with the addition of three or four minims of 1 in
+1000 solution of adrenalin chloride to each ounce. Several ounces of
+this preparation may be used with the greatest safety.
+
+Allen makes the following statement regarding this drug:--“After a
+rather extended experience, including a large number of cases embracing
+the entire field of surgery, in which this agent has been almost
+exclusively used, we have failed to note a single case in which there
+has been any unpleasant local or constitutional action. We, therefore,
+feel thoroughly justified in unqualifiedly recommending it as the
+safest, most reliable, and satisfactory of any local anæsthetic agent
+yet introduced.”
+
+
+                             Tropacocaine.
+
+This drug was first isolated from the leaves of the coca plant of Java,
+but is now prepared synthetically. Its formula is C_{15}H_{19}NO_{2}.
+Its action is exactly the same as that of cocaine, except that it
+is one-half as toxic and the duration of anæsthesia is shorter. The
+hydrochloride is freely soluble in water, and can be boiled without
+fear of decomposition. It is the agent which is most suitable for
+spinal anæsthesia, as fewer unpleasant effects have followed its use
+than that of any other drug.
+
+
+                               Stovaine.
+
+Stovaine is the hydrochloride of a synthetic compound of the benzoyl
+group. It occurs as a white crystalline powder, soluble in water, 1 in
+14. Its solutions withstand boiling, but are decomposed when heated
+to 120°C. Its action is the same as that of cocaine, except that it
+is slightly less toxic and less powerful. It has a distinct irritant
+effect locally. When injected in dilute solution, it produces a slight
+burning pain before anæsthesia appears, and very often a distinct
+inflammatory reaction persists for some time after the operation. It is
+therefore unsuited for local anæsthesia. It has been widely used for
+the production of spinal anæsthesia, especially by the French school,
+but since its injurious effects on nerve tissues have become more
+apparent, it has been less used than formerly.
+
+
+                               Eucaine.
+
+Eucaine was introduced as a substitute for cocaine, and, before the
+introduction of novocaine, was extensively used. It has a similar
+action to cocaine, and although it is less toxic, it is by no means
+free from danger unless it is used in very dilute solutions. It is a
+vaso-dilator, and must therefore be used in combination with adrenalin.
+It can be boiled without undergoing decomposition, and is practically
+non-irritant. It has been largely superseded by novocaine.
+
+
+                    Quinine and Urea Hydrochloride.
+
+The use of this drug for purposes of local anæsthesia is still in the
+experimental stage. It is made by adding urea to a solution of quinine
+in hydrochloric acid. The crystals are soluble in their own weight of
+water. For the production of local anæsthesia it is used in strengths
+of ·25 to 1 per cent. It is free from toxic effects, and its solutions
+can be sterilised by boiling.
+
+The striking feature about this drug is the extraordinary duration of
+the anæsthesia, this being from one to six days. It has therefore been
+used by Crile and other American surgeons to prevent pain during the
+first few days after operation. The great drawback to its use, however,
+is that it causes a persistent indurated condition of the tissues which
+interferes with primary union, and which is sometimes followed by
+actual sloughing. In addition, it is now established that its use has
+been followed by tetanus in several cases, and it is recommended that a
+dose of antitetanic serum should be given immediately before or after
+the injection of quinine.
+
+Although the action of this drug is of great interest, it cannot be
+recommended at present for ordinary purposes.
+
+
+                              Adrenalin.
+
+Adrenalin is obtained as an extract from the suprarenal glands of
+animals. It is a greyish white powder, slightly soluble in water, and
+readily so in weak acids. The usual preparation is a 1 in 1000 solution
+of adrenalin chloride in normal saline. It contains ·5 per cent. of
+chloroform as a preservative. The drawback to the animal extract is
+that the solution does not keep well, decomposition being indicated by
+a brownish colour. Of late a synthetic preparation has been introduced,
+which appears to have the same action, and which can be sterilised by
+boiling.
+
+The action of the drug is to cause marked vaso-constriction by direct
+action on the vessel walls. It has no analgesic action, and is used as
+an addition to solutions of anæsthetic drugs. The advantages of its use
+are that the action of the anæsthetic is concentrated and prolonged,
+owing to the delay in absorption, and that the field of operation is
+rendered practically bloodless. In large doses it may produce toxic
+symptoms in the form of palpitations and breathlessness, or even actual
+syncope, so that care is necessary in its use. For purposes of local
+anæsthesia, it is added to the solution of the anæsthetic drug in the
+strength of 3 drops to the ounce, and large injections of this dilute
+solution may be made without risk. At least twenty drops may be safely
+given.
+
+
+                     Induction of Local Anæsthesia
+
+Local anæsthesia may be induced by the use of anæsthetic drugs in three
+ways--(1) infiltration anæsthesia, (2) regional anæsthesia, and (3) by
+application to a mucous surface or to the surface of the eye.
+
+INFILTRATION ANÆSTHESIA.--In this method anæsthesia is induced by
+injection of the drug directly into the tissues to be operated upon.
+This method acts by paralysing the sensory nerve-endings. Although
+the term anæsthesia is constantly used, it is, strictly speaking,
+an operative analgesia that is aimed at; it is a paralysis of the
+pain-conducting fibres, and not of those which conduct purely tactile
+sensations, the patient being often able to feel the contact of the
+fingers and instruments during the operation. True anæsthesia can be
+secured, but it is necessary to use considerably stronger solutions
+than those that are required for the production of analgesia.
+
+SOLUTION OF THE DRUG.--Novocaine is far superior to any other drug for
+infiltration anæsthesia. The strength for most purposes is ½ per cent.,
+though some operators find ¼ per cent. quite satisfactory. In specially
+sensitive parts, such as the nose, throat, or mouth, 1 or even 2 per
+cent. solutions may be preferable. Sufficient sodium chloride should
+be added to prevent osmosis of the solution into the tissue cells. The
+most satisfactory preparation is:--
+
+    Novocaine                       0·25, 0·5, 1 or 2 (¼ to 2 percent.)
+    Normal salt solution (half      100·0 (·45 per cent. NaCl)
+      strength)
+
+  [Illustration: Fig. 51. All-Metal Syringe for Infiltration
+  Anæsthesia.]
+
+Adrenalin is added to the solution in the proportion of 3 drops of 1 in
+1000 adrenalin chloride to the ounce, and as much as 6 ounces of this
+preparation may be safely given. The novocaine solution can be boiled
+before use, but the adrenalin must not be added until after boiling.
+
+For private practice it is sometimes convenient to procure the
+novocaine in tabloid form of definite strength combined with sodium
+chloride. These tabloids are added to the necessary amount of water,
+and the whole boiled. The adrenalin can then be added.
+
+CHOICE OF SYRINGE.--The best form of syringe for infiltration
+anæsthesia is the all-metal syringe illustrated in Fig. 51. It ought
+to have a capacity of at least 10 c.c. The advantage of the all-metal
+syringe over glass syringes is that it can be safely sterilised by
+boiling, and does not get broken. Between the syringe and the needle is
+a metal segment which is curved so that the needle is set at an obtuse
+angle to the syringe. This renders the infiltration of the tissues at
+the proper depth much easier. The needles employed are the ordinary
+hypodermic needles which are sold in small tubes. The sizes which
+should be selected are 1 inch, and 3 or 3½ inches. The needle fits into
+a hole in a small metal mount, which screws on to the intermediate
+metal portion. This section also is attached to the syringe by a screw,
+and these screw attachments have the advantage of rendering leakage
+impossible.
+
+Failing the syringe described, a 10 c.c. Record syringe will be found
+to be quite efficient, if suitable needles can be obtained. The
+syringe, needles, and glass measure for the solution should be boiled
+in plain water or normal saline, as soda interferes with the action of
+the drug.
+
+TECHNIQUE OF INJECTION.--The needle is introduced into the
+subcutaneous tissue, and pushed on slowly to its full length, the
+fluid being injected as the needle advances. The needle is then partly
+withdrawn, and pushed in in a different direction so as to infiltrate a
+fresh area. This procedure is repeated, and as wide an area as possible
+infiltrated from the one puncture. The needle can then be completely
+withdrawn and introduced at a fresh point which has already been
+rendered analgesic. The deeper tissues can nearly always be infiltrated
+from the surface, but if large blood-vessels traverse the region to be
+infiltrated, it may be necessary to defer the deeper injection until
+these have been exposed. It is wise to infiltrate wide of the intended
+line of the incision, since it is not possible to anticipate with
+certainty the extent of an operation until it has been commenced. The
+secret of successful anæsthesia is to employ plenty of the solution,
+and make the injection thorough.
+
+The skin over the area becomes blanched within a few minutes of the
+injection owing to the action of the adrenalin. Anæsthesia is not
+usually complete until ten minutes have elapsed, and the operation
+should not be commenced until it has been made certain by suitable
+tests that the anæsthesia is complete. The duration of the anæsthesia
+is usually at least an hour and a half.
+
+It will be seen that the injection in the manner described above is
+entirely subcutaneous, the pain-conducting nerves from the skin being
+caught up by the drug as they traverse the superficial fascia in the
+area infiltrated. This method usually gives complete satisfaction,
+but some surgeons advise that the infiltration should be commenced
+with an _intra-dermal_ injection so as to reduce the pain of the
+needle punctures to a minimum. A fine needle is employed, the prick
+of which is practically painless. If the skin at the selected point
+is pinched up between the finger and thumb, and held firmly, this
+lessens its sensibility. The needle is advanced beneath the epidermis
+with a quick but light thrust. The injection into the substance of the
+skin causes a distinct wheal, which stands out from its surroundings
+like an urticarial wheal. From this starting-point a long needle can
+be introduced into the deeper tissues without pain. The intra-dermal
+injection may be carried along the whole length of the area to be
+infiltrated, each fresh puncture being made in the margin of the
+wheal-like area already anæsthetised.
+
+PRECAUTIONS.--The most careful asepsis is essential throughout.
+Infiltration with novocaine causes no interference with the healing
+of the wound, and although cases of sloughing of the tissues have been
+reported after its use, these are almost certainly due to infection
+of the wound. Care must be exercised also to avoid injecting the drug
+into a vein. When this accident takes place, the drug is carried at
+once into the general circulation, and may reach the higher nerve
+centres in such quantity as to produce serious toxic results. The use
+of adrenalin calls for special care and thoroughness in securing all
+bleeding-points, as, after the effect of the adrenalin passes off,
+even a slight ooze may increase and give rise to a hæmatoma which may
+jeopardise the healing of the wound.
+
+
+                         Regional Anæsthesia.
+
+In this method of producing anæsthesia, the sensory nerve paths are
+blocked by injecting the anæsthetic drug into, or around, a nerve
+trunk. By this procedure complete anæsthesia is produced in the area of
+distribution of the nerve, and the effect corresponds to a temporary
+physiological section of the nerve trunk. A temporary motor paralysis
+is also produced in a mixed nerve.
+
+TECHNIQUE.--The solution of the drug must be stronger than that
+employed for infiltration anæsthesia. A 2 per cent. solution of
+novocaine in half-strength normal saline with the addition of adrenalin
+is employed. The injection may be paraneural or intraneural.
+
+A _paraneural_ injection is made by passing a needle through the
+tissues to the known position of a nerve trunk and injecting the
+anæsthetic around it. The solution gradually diffuses into the nerve
+tissue, and anæsthesia of the nerve is produced. This method is open
+to the objection that unless the anæsthetic is accurately placed, no
+anæsthesia will result, and that in the case of certain nerves there is
+considerable risk of making the injection into a vein. The latter risk
+can be avoided by using a glassbarrelled syringe and applying a little
+suction before the injection is made; if a vein has been pierced, blood
+will enter the syringe.
+
+The _intraneural_ method is more accurate but requires the expenditure
+of considerable additional time and trouble, and is only employed
+where other methods of anæsthesia are not feasible. The tissue over
+the nerve having been infiltrated, the nerve is exposed by open
+dissection. It must not be pinched by forceps or other instruments,
+as such manipulations cause severe pain referred to its peripheral
+distribution. The injection should be made with the nerve lying in its
+bed by inserting a fine needle in the long axis of the nerve, first
+into the sheath, which is infiltrated, and then into the nerve itself.
+The infiltration of the nerve is continued until it presents a fusiform
+swelling and this may require from 5 to 15 minims of the solution.
+Complete anæsthesia of its entire distribution usually results in from
+five to ten minutes.
+
+A third method of inducing regional anæsthesia--first recommended by
+Hackenbruch--which is worth mention, is by the production of a ring
+of infiltration around a peripheral part, such as a finger, or around
+and underneath a tumour. By this means the nerve fibres are caught up
+by the anæsthetic and their conductivity interrupted as they enter the
+area to be operated upon. In dealing with such conditions as a large
+lipoma, or an umbilical hernia, it may be possible to avoid the use of
+an excessive amount of anæsthetic solution by employing this method.
+
+
+    Methods of Application of Infiltration and Regional Anæsthesia.
+
+It is sometimes stated that local anæsthesia should be limited to
+small and superficial operations, but with a knowledge of anatomy and
+of the correct technique, there are few operations which the surgeon
+cannot undertake with this form of anæsthesia. If we remember that the
+mortality from the anæsthetic is practically nil, it is obvious that it
+is often the duty of the operator to give the patient the choice of
+local anæsthesia. In urgent conditions in which the administration of a
+general anæsthetic would be attended with great danger, it is often a
+life-saving measure. Either infiltration or regional anæsthesia may be
+used alone; in some cases it is convenient to combine the two methods.
+
+
+                  Operations on the Upper Extremity.
+
+Regional anæsthesia is sometimes employed in operations on the upper
+extremity in conditions, such as diabetic gangrene or advanced cardiac
+disease, where a general anæsthetic is contra-indicated. In similar
+conditions in the lower extremity, spinal anæsthesia is usually
+preferred, though it is quite possible to anæsthetise the lower limb
+by blocking the sciatic, femoral, and lateral cutaneous nerves with a
+local anæsthetic. Crile lays great stress on the blocking of nerves
+with a local anæsthetic during operations on the limbs as a means of
+preventing shock, even where a general anæsthetic is being employed.
+The effect of the local anæsthetic is to prevent the impulses which
+produce shock from passing up to the higher centres. Only those methods
+which are applied to the upper extremity need special description.
+
+ANÆSTHESIA OF THE WHOLE ARM.--The nerves of the upper extremity are all
+derived from the brachial plexus except the intercosto-brachial. This
+nerve, which is the lateral cutaneous branch of the second intercostal,
+crosses the axilla and pierces the deep fascia on the medial side of
+the arm. It supplies the skin on the dorsal part of the medial aspect
+of the upper arm. The lateral cutaneous branch of the third intercostal
+nerve sometimes crosses the axilla also, and reaches the medial
+side of the arm. Injection of the brachial plexus produces complete
+analgesia of the shoulder and entire arm, and is particularly suited
+to high amputations and disarticulations at the shoulder. If the area
+supplied by the intercosto-brachial is encroached upon, this can be
+anæsthetised by infiltration with a few drams of solution injected
+subcutaneously along the floor of the axilla from its lateral and
+posterior borders.
+
+METHOD.--The injection may be intraneural or paraneural. The
+intraneural is made after exposing the plexus by an incision under
+infiltration anæsthesia from the junction of the middle and lower
+thirds of the sterno-mastoid to the union of the middle and lateral
+thirds of the clavicle. It is found lying on the scalenus medius and
+each of its branches is separately injected with a few drops of 5 per
+cent. solution of novocaine containing a few drops of adrenalin to the
+ounce.
+
+The paraneural injection is less satisfactory, since the nerves
+are too large to be readily penetrated in effective quantities by
+the anæsthetic solution, and since there are numerous veins in the
+neighbourhood into which the solution may be accidentally injected with
+dangerous results.
+
+The injection is usually made above the clavicle. In this region the
+plexus lies mainly above and to the lateral side of the third part
+of the subclavian artery, the lowest trunk lying directly behind the
+vessel as it rests on the first rib. The position of the artery is
+first localised with the finger by its pulsations, and the skin and
+subcutaneous tissue infiltrated immediately above the mid-point of
+the clavicle. From this point a long fine needle, unattached to the
+syringe, is passed downwards, backwards, and medially in the direction
+of the second or third thoracic spine. The distance to which the
+needle penetrates varies from 2 to 4 c.m. When the plexus is reached a
+slight radiating pain is felt down the distribution of the radial or
+median nerve. At this point the needle is held stationary, the syringe
+attached, and the injection made. The reason for not attaching the
+syringe earlier is that should the artery be entered, blood will flow.
+This accident is of little consequence, the needle being withdrawn
+slightly and introduced a little more laterally. About 10 c.c. of a
+2 per cent. solution of novocaine and adrenalin is injected; the
+needle is then slightly withdrawn and a further 10 c.c. injected in the
+neighbourhood. Anæsthesia occurs in from three to fifteen minutes.
+
+  [Illustration: FIG. 52.--Point at which the needle
+  is introduced in paraneural injection of brachial plexus.]
+
+The individual nerves of the upper limb can be readily injected. The
+_median_ can be exposed at the bend of the elbow for an intraneural
+injection, or a needle may be passed under the tendon of the palmaris
+longus at the wrist for a paraneural injection. The _ulnar_ can be
+easily reached as it lies on the posterior aspect of the medial
+epicondyle of the humerus for a paraneural or intraneural injection.
+The _superficial radial_ can be reached for a paraneural injection
+about two inches above the wrist to the lateral side of the tendon of
+the brachio-radialis (supinator longus). The injection is made into the
+deep fascia, and carried across the lateral border of the forearm for
+about an inch, to ensure reaching all the branches of the nerve.
+
+The _medial antibrachial_ (internal) _cutaneous_ can be blocked on
+the front of elbow by a paraneural injection about half an inch
+medial to the biceps tendon, and the _lateral antibrachial cutaneous_
+(musculo-cutaneous) at a corresponding point on the other side of the
+tendon.
+
+ANÆSTHESIA OF THE ARM BELOW THE ELBOW.--In operations below the elbow,
+in conditions in which a general anæsthetic is not permissible, as in
+diabetes, nephritis or advanced cardiac disease, a full anæsthesia
+can be obtained by intraneural injection of the median, ulnar, and
+radial (musculo-spiral) nerves, combined with paraneural injection
+of the medial and lateral antibrachial cutaneous. The median and
+radial are each exposed by an incision under infiltration anæsthesia,
+the radial being exposed in the groove between the brachialis and
+brachio-radialis. The infiltration to expose the median nerve usually
+blocks the anterior branch of the medial antibrachial cutaneous. To
+make certain that the posterior branch is also anæsthetised, it is
+advisable to inject a little anæsthetic solution over the front of the
+medial epicondyle. The intraneural injection into the ulnar nerve can
+often be made without exposing it.
+
+ANÆSTHESIA OF FINGER.--The paraneural method applied to the digital
+nerves at the root of the finger gives perfect results. A circle of
+anæsthetic solution is first injected round the root of the finger.
+The needle is then passed through the infiltrated skin on each side of
+the finger, and a few drops of ½ per cent. novocaine solution injected
+around the nerves. Complete anæsthesia of the finger results in a few
+minutes.
+
+IN THE LOWER LIMB injection of individual nerves is rarely employed,
+as anæsthesia is easily obtained by the method of spinal analgesia.
+The _lateral cutaneous_ can be injected as it lies immediately medial
+to the anterior superior iliac spine emerging from under cover of the
+inguinal ligament. This procedure may be useful in obtaining skin
+grafts, the grafts being taken from the antero-lateral aspect of the
+thigh. Amputations in the middle third of the thigh have been performed
+by injecting the sciatic, the posterior cutaneous (small sciatic), the
+femoral (anterior crural), and the lateral cutaneous at the root of the
+limb. The obturator nerve is difficult to find and anæsthetise in such
+cases. Operations below the knee can be painlessly performed by this
+method of anæsthesia.
+
+
+                        Operations on the Neck.
+
+TRACHEOTOMY.--This operation is conveniently and safely performed under
+infiltration anæsthesia. The anæsthetic solution is injected in the
+usual way in the line of the incision down to the trachea but not into
+it, as the trachea itself is insensitive to pain.
+
+GOITRE.--A parenchymatous or adenomatous goitre can be readily
+removed under local anæsthesia, though the administration of ether by
+intra-tracheal insufflation is usually to be preferred. The principal
+nerve supply to the field of operation is derived from the cervical
+plexus, whose branches become superficial about the middle of the
+posterior border of the sterno-mastoid. An intradermal injection may
+be made first at this point, and a longer needle then passed down
+to the posterior border of the muscle, and an area of infiltration
+produced. From this point the needle is directed first upwards and
+then downwards round the margin of the goitre so as to produce a zone
+of infiltration. The same procedure may be repeated on the opposite
+side, so that the whole gland is surrounded with a zone of infiltration
+with a special depot of solution around the branches of the cervical
+plexus. Where only one lobe is involved, it is sufficient to carry the
+injection down in the middle line after one side has been encircled.
+When the sheath has been incised and the surface of the gland exposed,
+the isthmus is infiltrated and divided. The affected half of the gland
+is then rolled outwards, and the attachments between the posterior
+aspect of the gland and the larynx and trachea are infiltrated, special
+attention being paid to the upper pole. The rest of the operation can
+then be carried out painlessly.
+
+EXOPHTHALMIC GOITRE may also be operated upon under local anæsthesia
+after a preliminary hypodermic injection of morphia and scopolamin,
+though many operators prefer a general anæsthetic on account of the
+nervous state of the patient. In bad cases a procedure which is
+often of great value is ligature of the superior thyroid artery on
+both sides under local anæsthesia. After ligature of the vessels a
+colloid degeneration takes place in the gland, and the symptoms of
+hyperthyroidism subside. After a delay of two or three months it may
+be possible to carry out the radical operation with little or no
+danger. The incision is two and a half inches in length, and crosses
+transversely the central part of the thyroid cartilage. The line of the
+incision is infiltrated with novocain solution in the ordinary way, and
+both superior thyroid arteries exposed and ligatured.
+
+
+                       Operations on the Thorax.
+
+The greater part of the wall of the thorax is supplied by the
+intercostal nerves. In front the supraclavicular nerves come down
+as far as the second intercostal space or sometimes as far as the
+nipple, and the lateral and medial anterior thoracic nerves supply
+the pectoral muscles, sending a few twigs to the overlying skin. The
+long thoracic nerve extends down the side of the chest, supplying the
+serratus anterior. The intercostal nerves can be blocked in the region
+of the angles of the ribs and the supraclavicular by carrying a line of
+infiltration along the clavicle. The anterior thoracic can be blocked
+by deeper injections. In this way the greater part of the chest wall
+and the pleura can be anæsthetised.
+
+ACUTE EMPYEMA.--This operation should always be performed under local
+anæsthesia. Exhaustion from septic absorption and from the antecedent
+pneumonia or other disease, with the dyspnœa from the pressure of the
+pus on the lung may render a general anæsthetic highly dangerous. The
+method of producing local anæsthesia is simple and easily carried out.
+A point is selected on the rib which is to be resected a short distance
+behind the line of the incision and an intra-dermal injection made with
+a fine needle. A long needle is then substituted and passed down to the
+upper border of the rib until it reaches the plane between the external
+and internal intercostal muscle, the injection being continued lightly
+as it advances. When the desired point is reached one or two drams of
+the solution are injected. The needle is then slightly withdrawn and
+passed to the lower border of the rib to reach the same plane and the
+same procedure carried out. The infiltration is then carried along
+the line of the incision or it may be made to pass obliquely upwards
+to the rib above and obliquely downwards to the rib below so as to
+catch up the nerves coming from behind into the area of operation. The
+anæsthesia of soft parts, bone, and pleura is perfect after the above
+injection.
+
+
+                      Operations on the Abdomen.
+
+The anterior abdominal wall, including the anterior parietal
+peritoneum, is supplied by the lower six intercostal nerves, the last
+thoracic nerve, and the ilio-hypogastric and ilio-inguinal nerves
+from the first lumbar. It is a very interesting and important fact
+that, although the parietal peritoneum is exceedingly sensitive to
+touch and pain, the visceral peritoneum and the viscera themselves
+are insensitive. When operations are performed under local anæsthesia
+of the abdominal wall, the viscera can be freely handled or incised
+without the patient experiencing the slightest discomfort, provided
+that the parietal peritoneum is not put upon the stretch by traction
+on the mesentery or other peritoneal attachment. Thus the colon
+can be opened twenty-four or forty-eight hours after being brought
+outside the abdominal wall without any anæsthetic in the operation of
+colostomy. Local anæsthesia is therefore well adapted to cases in which
+a small amount of manipulation of the viscera is required, and where a
+general anæsthetic would be dangerous, as in grave cases of intestinal
+obstruction and in cases of carcinoma of the œsophagus with weakness
+and loss of flesh from starvation.
+
+GASTROSTOMY.--This operation is commonly performed under local
+anæsthesia and may be taken as an illustration of the procedure
+employed. The incision is made through the middle of the left rectus
+and is about two and a half or three inches long, beginning about an
+inch below the costal margin. An intradermal wheal is established at
+the middle of the proposed incision. A long needle is entered at this
+point and passed first upwards and then downwards in the line of the
+incision, infiltrating the subcutaneous fat as it goes. The needle is
+then passed in through the anterior wall of the rectus sheath, this
+being easily recognised as a plane of decided resistance. The needle
+is advanced a little inside the sheath, the injection being continued
+as it advances. The same procedure is repeated at various points along
+the line of the incision. The extra-peritoneal fat may be infiltrated
+in the same way, the posterior wall of the sheath being identified
+as a deeper plane of resistance and gently pierced. This step may be
+deferred until the posterior wall of the sheath has been exposed.
+The infiltration may be completed by forming a line of intradermal
+infiltration along the line of incision, though this last step can
+often be omitted.
+
+The abdomen can then be opened painlessly. The only step in the
+operation which may cause a little discomfort is the traction which may
+be necessary to bring the shrunken stomach down from under cover of the
+ribs. The incision into the stomach is quite painless.
+
+GASTRO-ENTEROSTOMY can be performed under local anæsthesia, the only
+special step required being infiltration of the meso-colon before it is
+perforated.
+
+APPENDICECTOMY is not suitable, as a rule, for local anæsthesia. If the
+cæcum is fixed or the appendix bound down by adhesions, the traction
+necessary to bring the appendix to the surface causes considerable pain.
+
+In ACUTE OBSTRUCTION, when the procedure of enterostomy has been
+decided upon owing to the gravity of the patient’s condition, local
+anæsthesia is often of great value. The abdominal wall is infiltrated
+in the manner described, and a distended loop of bowel brought to the
+surface and sutured to the parietal peritoneum. A Paul’s tube can then
+be introduced.
+
+INGUINAL HERNIA. Local anæsthesia is specially suited to cases of
+strangulated hernia, but it may be employed in the ordinary case. It
+should be pointed out that spinal anæsthesia gives equally good results
+and is less troublesome to carry out.
+
+The injection is commenced with a fine needle a little beyond the
+lateral end of the proposed incision. An intradermal wheal is produced
+at this point, a long needle introduced into the subcutaneous tissue,
+and about half-an-ounce of anæsthetic solution injected in this
+position. The needle is then passed downwards and medially, and the
+subcutaneous fat infiltrated in the line of the incision. The needle
+is then partly withdrawn and again advanced until it reaches the
+resistance of the aponeurosis of the external oblique. This is gently
+pierced and about half-an-ounce of solution injected underneath so as
+to block the ilio-hypogastric and ilio-inguinal nerves. In most cases
+this is all that is necessary. As additional precautions the line of
+incision may be infiltrated intradermally, and an injection may be made
+around the neck of the sac after it is exposed.
+
+FEMORAL HERNIA.--A femoral hernia may be anæsthetised by infiltration
+along the line of the incision, or by injecting around the
+circumference of the hernia after the method of Hackenbruch. After
+the sac has been exposed and defined, it is necessary to inject some
+novocaine solution around the neck, care being taken to avoid the
+femoral vein which lies on the lateral side.
+
+UMBILICAL HERNIA.--Local anæsthesia is sometimes of great value in
+dealing with umbilical hernia, especially if it is strangulated, in
+stout patients who are bad subjects for a general anæsthetic. The
+injection is best made around the circumference of the hernia. Several
+intradermal injections are made at points around the swelling, and
+through these the long needle can be introduced and the deeper tissues
+infiltrated. If the muscles are fairly well defined and can be felt,
+they may be infiltrated at the commencement, but it may be advisable in
+fat subjects to inject only the subcutaneous tissues to begin with, and
+to delay the injection of the muscles and extra-peritoneal fat until
+the sac has been opened and a protecting finger can be introduced to
+guard the intestines. Omental adhesions can be divided without causing
+pain. If the intestines are extensively adherent to the sac it is
+better to infiltrate the points of adhesion, as extensive manipulation
+may cause cramp-like pains.
+
+After the circumferential injection has been made in these cases, it is
+best to wait for ten or fifteen minutes before making the incision in
+order to allow the anæsthetic solution to diffuse.
+
+SUPRAPUBIC CYSTOTOMY.--In operations for drainage of the bladder local
+anæsthesia is highly successful. The skin and subcutaneous tissues are
+infiltrated in the line of the incision. The needle is then carried
+between or through the recti muscles and several drams injected into
+the layer of fat in front of the bladder. It is unnecessary to inject
+the wall of the bladder itself.
+
+HÆMORRHOIDS.--In patients in whom there is some contra-indication to
+the use of a general anæsthetic the removal of hæmorrhoids can be
+carried out quite safely and painlessly under local anæsthesia. A
+circumferential injection is first carried out round the muco-cutaneous
+junction. It is best to start the infiltration about an inch out
+from the anus as the skin immediately around the anal orifice is
+extremely sensitive. The infiltration is made subcutaneously, and each
+re-insertion of the needle is made just short of where the previous
+injection stopped. When the circumferential injection has been
+completed, a finger is passed into the rectum, and the long needle
+introduced through the anæsthetised area, injecting as it advances, to
+a depth of about 2½ inches, keeping just outside the sphincters. Four
+such injections are made, one on each side of the bowel, one in front
+and one behind, from 5 to 10 c.c. being injected in each position.
+
+Anæsthesia results almost immediately and the anal canal can be readily
+dilated.
+
+THE TONGUE.--For the Whitehead operation of removal of one half of the
+tongue, complete anæsthesia can be obtained by the infiltration method.
+A long needle is introduced at the tip of the tongue, and the injection
+carried in the middle line to a point behind the tumour. The mucous
+membrane of the floor of the mouth and the glosso-palatine fold are
+infiltrated, and a last injection made across the affected half of the
+tongue well behind the tumour.
+
+The tongue can be anæsthetised also by blocking the lingual nerve
+with a paraneural injection. The nerve lies under the mucous membrane
+of the mouth opposite the last molar tooth. If the tongue is drawn
+well over to the opposite side, the nerve can be felt and the
+injection made around it. The only drawback to this method is that
+it does not anæsthetise the posterior third, which is supplied by the
+glosso-pharyngeal nerve.
+
+OPERATIONS ON THE SKULL AND BRAIN can be readily performed by
+infiltration of the scalp. In the later stages of the recent war, a
+large proportion of operations on the skull and brain were performed
+under local anæsthesia. The brain itself is insensitive to touch
+and painful stimuli, and infiltration of the scalp is all that is
+necessary. A 1 per cent. solution of novocaine with adrenalin has
+been commonly employed, and is injected into the subaponeurotic space
+so as to surround the field of operation with a wall of anæsthetic
+solution--the method of Hackenbruch. The advantages are that hæmorrhage
+is reduced to a minimum, and the head can be conveniently and safely
+elevated and the intra-cranial tension thus reduced.
+
+
+      Analgesia from the Application of Cocaine to the Eye or to
+                           a Mucous Surface.
+
+FOR OPERATIONS ON THE EYE.--Analgesia is obtained by the instillation
+of a few drops of a 4 per cent. solution into the conjunctival sac.
+This is repeated two or three times, and analgesia is obtained in five
+or ten minutes. It may be necessary to repeat the instillation during
+the course of the operation.
+
+FOR OPERATIONS ON THE NOSE, PHARYNX, OR LARYNX cocaine is commonly
+used. A 5 or 10 per cent. solution is employed and is merely painted
+on the surface. Care must be taken that such strong solutions are not
+swallowed.
+
+
+
+
+                             CHAPTER XXI.
+
+                          SPINAL ANÆSTHESIA.
+
+
+Spinal Anæsthesia or _Analgesia_, consists in the production of
+analgesia in the lower extremities and in the lower part of the trunk
+by the injection into the subarachnoid space of an anæsthetic drug
+which blocks the spinal nerves as they enter and leave the spinal
+cord. The cord ends at the lower border of the first lumbar vertebra
+and the subarachnoid space at the second sacral vertebra so that there
+is a considerable area into which the injection may be made without
+risk of injury to the cord. It is, in reality, a special variety of
+regional analgesia, the anæsthetic being injected into that part of
+the subarachnoid space which is occupied by the cauda equina. The
+subarachnoid space of the medulla spinalis contains the cerebro-spinal
+fluid and communicates above with the subarachnoid space inside the
+skull and through the foramen of Magendie, with the ventricular system
+of the brain. The subdural space of the medulla spinalis is merely a
+capillary interval. At the upper end of the cauda equina the nerve
+trunks of the two sides are separated by a median interval--containing
+only the filum terminale--which has been termed the cysterna
+terminalis. It is into this median space that the injection is made, in
+order to avoid wounding the nerve trunks and to procure equal diffusion
+of the anæsthetic to both sides of the middle line. If the injection is
+made among the nerve trunks on one side, a unilateral anæsthesia may
+result, the drug being prevented from diffusing freely to the other
+side by the presence of the numerous nerves.
+
+The ligamentum denticulatum forms an imperfect scalloped septum between
+the posterior and the anterior nerve roots, passing from the surface
+of the cord to the dura mater. The presence of this septum probably
+explains the fact that the motor nerves are not affected with the same
+constancy and to the same extent as the sensory roots.
+
+
+                              Technique.
+
+The drug which is most commonly employed in the Edinburgh school is
+Tropacocaine, and the results of its use with proper technique are
+eminently satisfactory. The dose of the drug for most purposes is ·07
+gramme. Smaller doses are sometimes used but the larger dose gives
+more constant anæsthesia and appears to be well within the limits
+of safety. The dose is dissolved in 1 c.cm. of distilled water and
+sufficient sodium chloride added to make a solution isotonic with the
+cerebro-spinal fluid. A convenient method of obtaining the drug is
+in glass ampoules, each ampoule containing one dose, which has been
+carefully sterilised.
+
+  [Illustration: FIG. 53.--Needle and syringe for
+  spinal analgesia. Note the short oblique character of the
+  point of the needle.]
+
+The syringe and needle employed are illustrated in Fig. 53.
+
+The point of the needle must be sharp but short. If a needle with a
+long slender point is employed, only part of the point may enter the
+membranes; a free flow of cerebro-spinal fluid may then take place,
+but when the injection is made part of the anæsthetic solution escapes
+outside the membranes. The needle should he 3½ to 4 inches long and 1
+m.m. in diameter. A stylet fits inside the needle and prevents it from
+becoming blocked during the introduction. To prevent the possibility
+of rusting, both needle and stylet should consist of hard nickel. The
+barrel of the syringe must consist of glass so that the appearance
+of the cerebro-spinal fluid can be seen. The Record type is very
+satisfactory. The syringe usually supplied for spinal analgesia has
+a capacity of 2 or 3 c.cm., but one holding 10 c.cm. is more useful.
+Syringe and needle must be carefully sterilised by boiling in plain
+water; any trace of soda causes decomposition of the drug. The ampoule
+containing the tropococaine is sterilised in a strong antiseptic
+solution so as to avoid the possibility of contamination of the hands
+when the drug is being transferred to the syringe.
+
+_Method of Injection._--The patient should be given a hypodermic
+injection of ⅛ gr. of morphine and ¹⁄₁₅₀ gr. of scopolamine an hour
+before the operation. There are a number of minor variations in the
+method of making the spinal injection, but limitations of space forbid
+a discussion of theoretical questions and of the relative merits of
+the different procedures. Only one method, which has been found safe
+and reliable, will be considered here. The injection is made in the
+space between the third and fourth lumbar spines, the objective being
+the mid-line of the subarachnoid space between the two divisions of
+the cauda equina. The position of the patient is such that the spaces
+between the lumbar spines are opened up as widely as possible. The
+most convenient plan is to have the patient sitting on the table with
+the head and shoulders bent well forward (_see_ Fig. 54.) If the
+patient is unable to sit up, the injection may be made with him lying
+on his side, with the knees drawn up and the shoulders bent forward.
+
+  [Illustration:
+
+  FIG. 54. Position for the injection. The cross
+  indicates the point at which the lumbar puncture is
+  made--about half an inch from the median plane and in the
+  space between the third and fourth lumbar spines.]
+
+The skin of the back is carefully sterilised; painting with tincture of
+iodine serves admirably. The ampoule containing the tropacocaine is
+opened, and the drug sucked into the syringe through a spare cannula.
+The loaded syringe is then placed on a sterile towel at the back of the
+patient. With a little practice there is no difficulty in making the
+lumbar puncture. The fourth lumbar spine is located by noting the level
+of the highest point on the iliac crest--this may be indicated by an
+assistant. A line joining the highest points on the two iliac crests
+will pass through the tip of the fourth lumbar spine. When this process
+has been carefully identified, the needle is introduced half-an-inch to
+one side of the median plane and midway between the third and fourth
+spine. Some surgeons prefer to go in exactly in the middle line to make
+sure of entering the middle of the subarachnoid space, but in this
+position the tough supra-spinous and interspinous ligaments are met
+with, and to avoid the resistance of these it is best to keep a short
+distance out from the median plane. By carefully noting the direction
+of the needle, the cysterna terminalis can always be entered. The
+needle is passed forwards, very slightly upwards, and slightly medially
+so as to hit off the centre of the subarachnoid space. As the needle
+passes through the ligamentum flavum, there is a sudden diminution of
+resistance and immediately afterwards the point of the needle lies in
+the subarachnoid space. The passage of the needle through the membranes
+is sometimes accompanied by a slight pricking pain.
+
+The stylet is withdrawn at this stage and the cerebro-spinal fluid
+usually trickles out drop by drop. The syringe is picked up, carefully
+emptied of air bubbles, and fitted on to the needle. The piston is
+withdrawn until the syringe is filled with cerebro-spinal fluid, which
+mixes freely with the anæsthetic solution, and the contents then
+slowly injected. The 10 c.cm. syringe is to be preferred for this
+purpose as it is essential to mix the tropacocaine thoroughly with the
+cerebro-spinal fluid. If the smaller syringe is used, it should be
+refilled with cerebro-spinal fluid and emptied a second time so as to
+ensure thorough diffusion of the drug. The needle is then withdrawn and
+the puncture sealed with collodion.
+
+The injection should never be made until a free flow of cerebro-spinal
+fluid is obtained, since this is the only certain indication that the
+needle has entered the subarachnoid space. If failure is met with in
+the space between the third and fourth spines, the interspinous space
+above or below should be tried.
+
+After the injection has been completed the patient is placed flat on
+his back and then lowered into the Trendelenburg position. Analgesia
+appears first in the scrotum and perineum, extends down the medial
+side of the leg to the foot, then appears on the front of the leg, and
+travels up to the groin and the lower part of the abdomen. The progress
+of the analgesia is tested from time to time by lightly pinching
+or pricking the skin, the patient’s eyes being screened. When the
+analgesia reaches the level of the nipples, the patient is raised into
+the horizontal position and the the operation may be commenced. Some
+surgeons object to the lowering of the head as rendering paralysis of
+the respiratory centre from upward diffusion of the drug more likely.
+If tropacocaine is used in the dosage indicated and the table elevated
+when the anæsthesia reaches the nipple line, there seems to be little
+risk of this complication. If analgesia is only desired in the lower
+extremity, the lowering of the table may be omitted; but if a good
+anæsthesia is desired above the level of the groin, it should always be
+carried out.
+
+Analgesia is complete in five or ten minutes as a rule. The duration
+varies from three-quarters of an hour to an hour and a half. If a
+preliminary hypodermic injection of morphine and scopolamine has been
+given, the patient lies quietly and patiently until the operation is
+completed. In some cases the patient actually drops off to sleep from
+the effects of the morphine. It is not uncommon to observe a temporary
+nausea and faintness about fifteen or twenty minutes after the
+injection has been made, and it is good practice to give the patient a
+little brandy and water at this stage.
+
+
+                   Complications and After-Effects.
+
+A great deal has been written in the past with regard to unpleasant
+results of spinal analgesia, but most of these would appear to have
+been the result of faulty technique or of the use of an impure or
+irritating drug. When tropacocaine is used in the manner described, the
+usual result is that, except for occasional nausea and faintness at
+the commencement, the patient has a comfortable, painless operation,
+and a recovery which is unmarred by the sickness and other distressing
+symptoms which are so common after general anæsthesia.
+
+_Deaths_ have been recorded, and these have been ascribed to
+the drug having travelled too high and brought about paralysis of
+the respiratory centre in the medulla oblongata. Too much importance
+has probably been ascribed to these fatal cases. They have been most
+common in patients greatly enfeebled by shock, old age, or debilitating
+illness, who are liable to die during the operation whatever anæsthetic
+is used. Thousands of cases have been recorded without a death, and
+in the hands of surgeons of skill and judgment fatal cases are almost
+unknown.
+
+An occasional complication is severe _headache_ which may
+persist for a week or longer. Other complications are all exceedingly
+rare; paralysis of the lateral rectus muscle of the eyeball or of
+other ocular muscles has been recorded, and is probably due to toxic
+bye-products which are the result of impurity of the drug. Persistent
+nausea and paralysis of the bladder and rectum and even of the lower
+extremities have also been recorded, but are to be regarded as the
+greatest rareties, and probably due to impurity of the anæsthetic.
+
+
+                             Indications.
+
+Spinal analgesia may be used for any operation at or below the level of
+the umbilicus. Excellent anæsthesia is obtained for the operation for
+radical cure of umbilical hernia, but anæsthesia above this level is
+not so constant, and is regarded by many authorities as unsafe.
+
+The procedure is of special value in cases in which a general
+anæsthetic is unsafe:--(1) In old enfeebled patients suffering from
+strangulated hernia, enlarged prostate, disease of the female pelvic
+organs, and other conditions where anæsthesia is necessary below the
+umbilicus. (2) In patients who are already suffering, or who are likely
+to suffer, from severe shock. The drug has the same effect on the nerve
+trunks of the cauda equina as on the peripheral nerves--it causes
+blocking of the centripetal sensory impulses which are such a potent
+factor in the causation of shock.
+
+(3) In diabetic gangrene spinal analgesia is the safest form of
+anæsthesia to employ.
+
+
+                          Contra-Indications
+
+Children up to the age of fourteen or so are apt to be frightened,
+and spinal analgesia is better avoided except in special cases. It
+is contra-indicated also in septic conditions on account of the
+possibility of septic meningitis resulting from metastasis of the
+infection, the drug having possibly the action of lowering the vitality
+of the cord and meninges. In tuberculosis and syphilis it is better
+avoided for the same reason. It should not be used where organic
+disease of the spinal cord or brain is already present.
+
+
+                    Analgesia Produced by Freezing.
+
+A transient analgesia can be produced by freezing the skin. An ether
+spray was formerly employed, but was found to be troublesome and
+inconvenient. The most convenient procedure consists in freezing the
+part by means of a spray of ethyl chloride. This drug is supplied in a
+glass cylinder with a very fine outlet so that it breaks up into a fine
+spray as it escapes. The cylinder is held about 8 or 10 inches from the
+patient’s skin, and pressure applied with the thumb to a stopcock on
+the neck of the cylinder. Under the influence of the heat of the hand
+the liquid escapes in a fine jet which impinges on the patient’s skin.
+Freezing takes place in a few seconds, the frozen patch becoming hard
+and white. The freezing can be hastened by blowing on the skin.
+
+This method is only suitable for the opening of small abscesses and
+other procedures requiring a very short anæsthesia. The anæsthesia is
+very imperfect, and only lasts for a few seconds. Many patients appear
+to have as much pain with this form of anæsthesia as without it.
+
+
+
+
+                              APPENDIX I.
+
+         SOME EXPERIMENTAL OBSERVATIONS BY THE AUTHOR UPON THE
+                 PHYSICAL FACTS OF ETHER EVAPORATION.
+
+
+The apparatus was very simple. It consisted of a pump which would
+propel air towards the ether bottle; a glass bottle containing ether,
+the roof of which was pierced by two tubes, one of which carried the
+air from pump to bottle, and the other from bottle to a Waller’s tube,
+where it was collected. The percentage of ether in the air was then
+estimated by Waller’s gravimetric method. The ether jar stood in a
+water bath which could be either left otherwise empty or filled up
+with water of known temperature. The following tables show some of the
+results. In each case, the air was propelled for five minutes, by which
+time the cooling effect upon the ether was very marked; the figures
+given are averages taken from several observations.
+
+
+                               TABLE A.
+
+                  AIR BLOWING OVER SURFACE OF ETHER.
+
+  +---------------------+----------------+----------+--------------+----------+
+  |   Temperature of    |  Quantity of   |   Rate   | Temperature  |          |
+  |    Bath (Fahr.)     |  ether before  |    of    |   of ether   |Percentage|
+  | before experiment.  |experiment.     |   pump.  |(Fahr.) at end|obtained. |
+  |                     |                |          |of experiment.|          |
+  +---------------------+----------------+----------+--------------+----------+
+  |         75          |    100 c.c.    |    30    |    50 F.     |   12·7   |
+  |         85          |    100 c.c.    |    30    |    52 F.     |   12·8   |
+  |         75          |    100 c.c.    |    90    |    45 F.     |    8·7   |
+  |         85          |    100 c.c.    |    90    |    45 F.     |    8·8   |
+  |  No water in bath   |    100 c.c.    |    30    |    32 F.     |    8·2   |
+  |  No water in bath   |    100 c.c.    |    90    |    23 F.     |    5·4   |
+  |  No water in bath   |    200 c.c.    |    30    |    38 F.     |    9·6   |
+  |  No water in bath   |    200 c.c.    |    90    |    29 F.     |    6·6   |
+  +---------------------+----------------+----------+--------------+----------+
+
+
+                               TABLE B.
+
+Showing increased percentage obtained by “bubbling through” instead of
+“blowing over” ether--
+
+    WATER BATH AT 75° FAHR.
+
+    Quantity of ether.     Rate of pump.
+        100 c.c.                30
+
+    Air blown over surface of ether gave percentage of ether       12·8
+    Air bubbled _through_ ether                                    23·8
+
+
+                               TABLE C.
+
+Showing amounts of ether vaporised at varying pump rates. In each case,
+the temperature of the water bath was 75, and the initial amount of
+ether was 100 cc.--
+
+    Pump      Amount of Ether
+    Rate.       Vaporised.
+     30          30 c.c.
+     90          38 c.c.
+
+These experiments justify one in drawing the following conclusions:--
+
+   1. The effect of a water bath has a marked effect in increasing
+   the strength of the vapour yielded, but small variations in the
+   temperature of the bath (as between 75 and 85 Fahr.) have but
+   little effect.
+
+   2. If ether is vaporising quickly, it cannot pick up heat from
+   the water bath as quickly as it is losing its own heat. Though
+   not shown in the tables, the actual loss of temperature on the
+   water bath was small--about 2 degrees Fahr. during the five
+   minutes experiment.
+
+   3. The more forcible the blast of air blown over or through
+   the ether, the less the percentage of ether yielded. Table C
+   shows that this loss of percentage is not compensated for by an
+   increase in the total amount vaporised.
+
+Of course, these results only apply to the case of a strong current
+of air. If the current of air were _very_ small, the ether could
+pick up heat as fast as it parted with it, and within moderate degrees
+a little increase of the air stream would increase the total amount of
+ether vaporised without reducing the percentage strength.
+
+These results are of some practical importance in connection with
+so-called “vapour anæsthesia” as given for instance by Shipway’s
+instrument (page 90), and in devising and using the ether chambers of
+intratracheal apparatus.
+
+
+
+
+                             APPENDIX II.
+
+                THE PERCENTAGE STRENGTH IN OPEN ETHER.
+
+
+Hewitt and Syme (_Lancet_, 27th Jan. 1912) estimated the percentage
+of ether obtainable from an open mask with varying materials and
+quantities of the drug. The results are tabulated below:--
+
+
+                     A.--A WHOLE MASK JUST MOIST.
+
+    Material stretched   Number of   Percentage
+         on mask.         layers.     obtained.
+          Gauze              4          11
+                             8          11·4
+                            12          11
+          Flannel            1           8·0
+                             2           8·0
+          Lint               1          10·0
+
+
+                          B.--WHOLE MASK WET.
+
+          Gauze              4          12
+                             8          13·4
+                            12          14·0
+          Flannel            1           8·0
+                             2           8·0
+          Lint               1           8·0
+
+    By excessive douching the observers were able to obtain 17 per
+      cent.
+
+In these results, air and ether vapour were drawn by a pump through
+the material to imitate the inspiration, but no attempt seems to have
+been made to imitate expiration. The effect upon the material used of
+moisture condensed from the expired air is not taken into account
+in these experiments. This is a serious hiatus in the argument,
+particularly as regards lint. This material in actual use rapidly
+becomes quite sodden, and ether will not vaporise from it properly.
+
+In spite of this fault, these observations may probably be taken as
+being reasonably accurate.
+
+With them may be compared the figures of Karl Connell, who, working
+with quite accurate methods, estimated the percentages of ether
+necessary to induce and maintain anæsthesia:--
+
+          Period of Anæsthesia.                 Percentage.
+    First 5 minutes (_i.e._ induction)              18
+    Next 25    „                                    14
+    Next 30    „                                    12
+    Next 60    „                                    12·8
+
+“Bad” subjects on the average required an extra 4 per cent. during
+first half hour, feeble patients required 2 per cent. less.
+(_Journal_ of the American Medical Association, 22nd March 1913).
+
+
+
+
+                             APPENDIX III.
+
+               THE ACTION OF ANÆSTHETICS UPON THE BLOOD.
+
+
+                   _The Blood Gases in Anæsthesia._
+
+Buckmaster and Gardner (_Journal of Physiology_, vol. xli., p. 246),
+analysed the blood gases in various stages of chloroform anæsthesia,
+and some of their results are shown below in tabular form. They show a
+very definite reduction in the oxygen content of the blood. So far as
+one gathers from the text of the paper, the animals were not subjected
+to any considerable trauma during the progress of the anæsthesia, so
+that the figures arrived at with regard to the CO_{2} content do not
+bear upon the Acapnia question. If there was no trauma, there would be
+no deep breathing, and a reduction of CO_{2} could not be expected.
+
+ +---------------------------+------------------+-------------------+---------------+
+ |                           |Average volume in |Average composition|               |
+ |                           |c.c. per 100 c.c. |     per cent.     |   Relation    |
+ |                           |    of blood      |      of gas       |      of       |
+ |                           |------+-----+-----+-------------------|O_{2} to CO_{2}|
+ |                           |CO_{2}|O_{2}|Nitr.|CO_{2}| O_{2}|Nitr.|               |
+ +---------------------------+------+-----+-----+------+------+-----+---------------+
+ |Normal cats.               | 25·07|13·60| 1·00|  63·2| 34·28| 2·52|   1 to 1·84   |
+ |                           |      |     |     |      |      |     |               |
+ |Reflexes just re-appearing | 29·02|11·49| 1·33| 65·06| 25·44| 2·87|   1 to 2·55   |
+ |                           |      |     |     |      |      |     |               |
+ |Reflexes just disappearing | 29·57| 7·78| 2·15| 69·14| 18·17| 5·09|   1 to 3·8    |
+ |                           |      |     |     |      |      |     |               |
+ |2nd Stage Anæsthesia       | 36·00| 8·14| 1·49| 71·27| 16·12| 2·95|   1 to 4·32   |
+ +---------------------------+------+-----+-----+------+------+-----+---------------+
+
+
+                 _Other Blood changes in Anæsthesia._
+
+Hamburger and Ewing (_Journal_ of the American Medical Assoc. 1908)
+examined the blood changes incidental to surgical anæsthesia. Their
+results may be condensed as follows:--
+
+_Nitrous Oxide._--Hæmoglobin is not permanently decreased and no anæmia
+follows the administration. Hæmolysis is not increased. The coagulation
+time of the blood is not always affected in the same direction. Usually
+it is slightly increased.
+
+_Ether._--The hæmoglobin is slightly reduced and anæmia persists for
+seven to ten days. Hæmolysis is not however materially increased.
+There is some evidence of blood inspissation. The coagulation time is
+markedly increased.
+
+_Chloroform._--The hæmoglobin is reduced and a distinct anæmia
+produced. Hæmolysis is definitely increased. There is a slight increase
+in the coagulation time.
+
+
+
+
+                                INDEX.
+
+
+              A
+
+    Abdominal operations, ix, 7
+      local anæsthesia in, 187
+
+    Abdominal muscles, rigidity of, 19
+
+    Abnormalities of anæsthesia, minor, 38
+      major, 140
+
+    Acapnia, 10, 29, 39
+
+    Accidents of anæsthesia, 140
+
+    Acetonuria, 153
+
+    Acidosis, 153
+
+    Adenoids, 127, 166
+      in status lymphaticus, 148
+
+    Adrenalin, 175
+      danger of, with chloroform, 113, 166
+
+    Aedentulous patients, 23
+
+    After-effects of anæsthetics, _see_ Sequelae
+
+    Ages, dosage of morphia at various, 45
+      selection of anæsthetic at various, 164
+
+    Airshaft, natural, 96
+
+    Airway, natural, 15, 31, 114, 145
+      artificial, 23
+
+    Alcoholics, anæsthesia in, 2, 87, 103, 137, 165
+
+    Alkaloids, 12, 43, 88, 103
+
+    Aneurysm, 56
+
+    Anoci-association, 11
+
+    Anoxæmia, 15
+
+    Arm, management of in anæsthesia, 157
+      regional anæsthesia of, 181
+
+    Arteries, spouting of, x, 37
+
+    Arterio-sclerosis, 56, 167
+
+    Artificial respiration, 146
+
+    Asphyxia, 15
+
+    Athetosis, 38
+
+    Atropine, 43, 45, 112, 147
+
+    Auer and Meltzer, 96
+
+
+              B
+
+    Barth 3-way tap, 50
+
+    Bicarbonate of soda in acidosis, 156
+
+    Bladder, reflexes from, 39, 168
+      local anæsthesia in operations upon, 190
+
+    Blistering, by chloroform, 109
+
+    Blood, changes in, during anæsthesia, 207
+      spouting of, from cut arteries, x, 37
+
+    Blood-pressure, in natural sleep, 1
+      in shock, 6
+      in asphyxia, 17
+      in nitrous oxide, 46
+      in ether, 75
+      in chloroform, 110
+      in ethyl chloride, 122
+      clinical observation of, 37
+
+    Blowing respiration, 34, 89
+
+    Boothby, on ether percentages, 99
+
+    Boyle, Mr Leonard, 70
+
+    Brachial plexus, nerve blocking in, 181
+
+    Brain, _see_ Nervous System
+      local anæsthesia for operation upon, 191
+
+    Breath-holding, 34, 112, 114
+
+    Breathing, deep (_see_ Acapnia)
+
+    Bronchitis, 150
+
+
+              C
+
+    Carbon-dioxide, 10, 18, 206
+
+    Cardiac cyanosis, 37
+
+    Cardiac disease, 107
+
+    Cardiac failure (_see_ Syncope)
+
+    Castration, anæsthesia in, 169
+
+    C.E. mixture, 84, 134, 137
+
+    Cells, nerve, changes in, 5
+
+    Centripetal impulses, 6
+
+    Children, 45, 94, 125, 164
+
+    Chloretone, 93
+
+    Chloride of ethyl (_see_ Ethyl Chloride)
+
+    Chloroform, administration of, 113
+      decomposition of, 109
+      delayed poisoning by, 153
+      physiology of, 109
+
+    Choice of anæsthetics, 162
+
+    Circulation, observation of, x, 37
+      in shock, 10
+      in asphyxia, 17
+      in valved breathing, 29
+      in nitrous oxide, 46
+      in ether, 75
+      in chloroform, 110
+      in ethyl chloride, 122
+      in C.E. mixture, 131
+      failure of (_see_ Syncope)
+
+    Circumcision, anæsthesia in, 169
+
+    Clarke’s apparatus, 69
+
+    Clenching of Jaws, 15, 24
+
+    Clinical phenomena of asphyxia, 18
+      of normal anæsthesia, 33
+
+    Closed ether, 78
+
+    Closed method, features of, 29
+
+    Clover’s inhaler, 78, 138
+
+    Cocaine, 170
+
+    Collapse (_see_ Syncope)
+
+    Conduction of nerve impulses, 3
+
+    Connell, Karl, 90, 205
+
+    Conjunctival reflex, 31, 35
+
+    Convulsions, 17
+
+    Corneal reflex, 32, 35
+
+    Crile, Prof., 5, 9
+
+    Crowing respiration, 16, 169
+      night crowing, 148
+
+    Cyanosis, 18, 37, 53
+
+    Cylinders for nitrous oxide, 43
+      for oxygen, 64
+
+
+              D
+
+    Dangers of chloroform, Prof. L. Hill upon, 120
+
+    Death, causes of, 17, 110, 140, 144, 148
+
+    Decomposition of chloroform, 109
+      of ether, 74
+
+    Deep breathing, 10
+
+    Degrees of anæsthesia, 31
+
+    Dental anæsthesia, 54, 57, 128, 131, 163
+
+    Depth of anæsthesia, 36
+
+    Dextrose in acidosis, 156
+
+    Difficulties of anæsthesia, major, 140
+      minor, 38
+
+    Dilatation of pupils, 5, 17, 35, 53, 66, 125, 136, 141, 143
+
+    Disease, relation of anæsthesia to, 166
+      acute infectious, 168
+
+    Dislocations, anæsthesia in reduction of, 164
+
+    Dorsal position, 157
+
+    Dosimetric method for chloroform, 114
+      for ether, 90
+
+    Dott, Mr N., direct laryngoscope, 104
+
+    Douche method, 20
+
+    Dread (_see_ Fear)
+
+    Drop bottles; chloroform, 117
+      ether, 83
+
+    Drop method, 30, 83
+
+    Drugs for local and spinal anæsthesia, 170 to 174
+
+
+               E
+
+    Emphysema, 167
+
+    Empyæma, 167, 187
+
+    Enema, before operation, 42
+
+    Ether, 74, _et seq._
+      closed, 78
+      intratracheal, 96
+      open, 83
+      physiology of, 75
+      rectal, 93
+      warmed vapour, 90
+
+    Ether, respiratory sequelæ of, 150
+
+    Ether tremor, 38
+
+    Ethyl chloride, 122, _et seq._
+      combined with nitrous oxide, 128
+      freezing anæsthesia by, 200
+
+    Eucain, 174
+
+    Excitement (_see_ Struggling)
+
+    Extraction of teeth (_see_ Dental Anæsthesia)
+
+    Eye reflexes, definition of, 31
+
+
+               F
+
+    Face-down posture, 157
+
+    Face, adaptation of masks to, 21, 52, 84
+
+    Face-pieces for nitrous oxide, 51
+
+    False anæsthesia, 41
+
+    Faradism of motor nerves in anæsthesia, 3
+
+    Fat patients, 158, 165
+
+    Fatty changes after anæsthesia, 153
+
+    Fear, effects of, 9
+      prevention of, 11, 43, 88
+
+    Feeble patients, 168
+
+    Ferguson, Dr., W. J., 87
+
+    Fingers, regional anæsthesia for, 184
+
+    Flame, open, dangers of, 74, 104
+
+    Forceps, tongue, 24
+
+    Food before anæsthesia, 42
+
+    Foreign bodies in the larynx, 16
+
+    Freezing analgesia, 201
+
+    Fright (_see_ Fear)
+
+
+               G
+
+    Gags, 25
+
+    Gardner, Mr Bellamy, 23, 24, 83
+
+    Gas and air, 54
+
+    Gas and ether, 138
+
+    Gas and ethyl chloride, 128
+
+    Gas-oxygen, 60
+
+    Gasping, 40
+
+    Genito-urinary operations, 168
+
+    Glossotilt, 24
+
+    Glottis, spasm of, 16, 20, 26, 105
+
+    Goitre, anæsthesia for, 160, 185
+
+    Goitre, exopthalmic, 9, 167
+
+    Grey and Parsons on shock, 6
+
+    Guy, Dr Wm., 128
+
+    Guy-Ross, gas oxygen method, 131
+
+    Gwathmey, warmed ether vapour, 90
+      oil-ether, 93
+
+
+               H
+
+    Hæmorrhage, as a factor in shock production, 9
+      observation of, by anæsthetist, x, 37
+
+    Hæmorrhoids, local anæsthesia for, 191
+
+    Harcourt, Vernon, 114
+
+    Head and neck operations, position for, 158
+
+    Head and neck, raising, 152
+      lowering, 110, 145
+      extra pillow in deep chested patients, 157
+
+    Heart, failure in asphyxia, 17
+      observation of, 37
+      action of ether upon, 75
+      of chloroform upon, 110
+      of ethyl chloride upon, 122
+      failure of, in secondary syncope, 144
+
+    Heart disease, anæsthetics in, 167
+
+    Henderson, Yandell, 10, 29
+
+    Hernia, local anæsthesia in, 189
+
+    Heroin, 44
+
+    Hewitt, Sir Frederick, 22, 50, 62, 81, 137
+
+    Hill’s direct laryngoscope, 104
+
+    Hill, Prof. Leonard, 111, 120
+
+    Hornabrook, 87, 123
+
+    Hydrochloric acid, as an impurity in chloroform, 109
+
+    Hypnotics, 12, 42
+
+    Hypodermic medication, 12, 42
+
+
+               I
+
+    Impurities of anæsthetics, 74, 109, 122
+
+    Infiltration analgesia, 175
+
+    Inhalers, Clover, 78
+      Clarke, 68
+      Guy, 128
+      Guy-Ross, 130
+      Hewitt, 50, 62, 81
+      Junker’s, 115
+      Ormsby, 81
+      Paterson, 58
+      Rendle, 135
+
+    Inhibition, vagal, 111, 143
+
+    Intestinal obstruction, 141, 189
+
+    Intranasal surgery, 160, 166, 192
+
+    Intratracheal method, 96
+      Kelly’s instrument for, 100
+      Shipway’s, 101
+
+    Inversion, Leonard Hill’s experiments upon, 110, 111
+
+
+               J
+
+    Jactitations, 53
+
+    Jaundice, 154
+
+    Jaws, clenching of, 15, 26
+      falling back of, 16
+      operations upon, 166
+      management of, in anæsthesia, 23, 85
+
+    Joints, anæsthesia in dislocation of, 164
+
+    Junker’s inhaler, 115
+
+
+               K
+
+    Kidney, position for operations upon, 168
+
+    Kelly’s intratracheal instrument, 100
+
+
+               L
+
+    Labour, anæsthesia in, 44, 169
+
+    Lane, Sir Arbuthnott, 14
+
+    Laryngeal stridor, 16, 20, 26, 40, 169
+
+    Levy, Goodman, 112, 145
+
+    Light anæsthesia, dangers of, in chloroform, 9, 112
+      Levy’s views, 113
+
+    Light reflex, 32
+
+    Local anæsthesia, 170 _et seq._
+
+    Lowering of head and shoulders, 110, 145
+
+    Lumbar puncture, site for, 196
+
+    Lungs, ventilation of, by normal breathing, 96
+      by intratracheal method, 97
+
+    Lymphatism, 148
+
+
+               M
+
+    Malcolm, J. D., 9
+
+    Marshall, Dr Geoffrey, 70
+
+    Masks for chloroform, 110
+      for ether, 82
+      for perhalation method, 28
+
+    Massage of heart, 148
+
+    Mechanical asphyxia, 15
+
+    Meltzer and Auer, on intratracheal method, 96
+
+    Menstruation, 169
+
+    Micturition before nitrous oxide, 51
+
+    Mixtures, C. E., 84, 134, 137
+      of nitrous oxide and oxygen, 60
+      of nitrous oxide and ethyl chloride, 128
+
+    Morphine, 12, 43, 152
+
+    Mouth, breathing through, 22
+
+    Mouth, operations upon, 165
+
+    Mouth props, 22
+
+    Mucus in air passages, 40
+
+    Musculo-spiral paralysis, 157
+
+    Muscles in anæsthesia, ix, 3, 19, 34
+
+    Muscle tone, 3, 19, 53
+
+
+               N
+
+    Nasal breathing, 23, 166
+
+    Naso-pharyngeal catarrh, 151
+
+    Nasal methods of giving nitrous oxide, 57
+
+    Nasal tube for Junker’s bottle, 119
+
+    Neck, position of, 20
+      relaxation of muscles of, 21
+      posture for operation upon, 159
+      tumours and inflammatory swellings in, 7, 166
+
+    Nephritis, influence of, upon choice of anæsthetics, 77, 168
+
+    Nervous system, effects of anæsthetics upon, 2, 75
+
+    Nerves, peripheral, unaffected by anæsthetics, 3
+
+    Nerve blocking, 12, 179
+
+    Night-crowing, 148
+
+    Nitrous oxide, 46
+      with air, 54
+      with ether, 138
+      with ethyl chloride, 128
+      nasal, 57
+      physiology of, 46
+      contra-indications to, 56
+
+    Nitrous oxide and oxygen, 8, 12, 60
+      various systems for, 67, 70, 130
+      for use in major surgery, 72
+      with ethyl chloride, 131
+
+
+              O
+
+    Obesity, 158, 165
+
+    Obstruction, intestinal, 141
+      respiratory, 15, 141
+
+    Oil ether, Gwathmey’s method of, 93
+
+    Oligæmia in shock, 10
+
+    Omnopon, 44
+
+    Open method, definition of, 28
+      chloroform, 117
+      ether, 83
+      ethyl chloride, 123
+
+    O’Malley’s technique for intra-nasal surgery, 160
+
+    Ormsby’s inhaler, 81, 137
+
+    Over-dosage, 36, 110, 144
+      with nitrous oxide, 54
+
+    Oxygen, reduction in blood in anæsthesia, 206
+      as a relief in asphyxia, 27
+      to old patients, 165
+      with nitrous oxide (_see_ Nitrous Oxide and Oxygen)
+      with nitrous oxide and ethyl chloride, 130
+
+
+               P
+
+    Paralysis, musculo-spiral, 157
+
+    Patella reflex in anæsthesia, 3
+
+    Percentages of chloroform and ether required in anæsthesia, 6
+      of chloroform, 111
+      of ether, 86, 99, 201, 204
+
+    Perhalation method, definition of, 28
+      ether (_see_ open Ether)
+
+    Phenomena of anæsthesia
+      normal, 33
+      abnormal, 38
+      of nitrous oxide, 52
+      of ethyl chloride, 125
+
+    Pericarditis as a cause of death in anæsthesia, 168
+
+    Phillip’s artificial airway, 23, 160
+
+    Physics of natural respiration, 96
+
+    Physiology of anæsthetic drugs, 1
+      of asphyxia, 17
+      of chloroform, 109
+      of ether, 75
+      of ethyl chloride, 122
+      of nitrous oxide, 46
+
+    Phthisis, 167
+
+    Pneumonia, post anæsthetic, 157
+
+    Position in anæsthesia, 157
+
+    Positive pressure in nitrous oxide, 52
+      in nitrous oxide and oxygen, 66
+
+    Post-chloroform poisoning, 153
+
+    Post anæsthetic complications, 150
+
+    Pregnancy, anæsthesia in, 169
+
+    Preliminary hypodermic medication, 11, 43, 152
+
+    Preparation of patient, 42
+
+    Primary syncope, 110, 143
+
+    Protection from shock by general anæsthetics, 8
+
+    Pulse, rate in shock, 6
+      clinical observation of, 37
+
+    Pupil, light reflex of, 32
+      size of, 35
+      in asphyxia, 17
+
+    Purging before anæsthetics, 40
+
+
+               Q
+
+    Quinine and urea hydrochloride, 174
+
+
+               R
+
+    Rebreathing method, 18
+      in nitrous oxide, 68
+
+    Rectal administration of ether, 93
+
+    Rectal saline, 42
+
+    Reflexes as a cause of shock, 4, 6
+      order of disappearance of, 3
+
+    Reflex, conjunctival, 31, 35
+      corneal, 32, 35
+      light, 32, 35
+      patella, 3
+      skin, 37
+
+    Reflex syncope, 8, 112, 145
+
+    Regional anæsthesia, 179
+
+    Renal disease, 163
+
+    Rendle’s cone, 135
+
+    Repeated administrations, 60, 156
+
+    Respiration, arrest of, 142
+      artificial, 146
+      blowing, 34, 89
+      crowing, 16
+      depressed, 39, 43
+      effect of morphia and chloroform upon, 43, 86
+      normal, 34
+      obstructed, 15, 141, 166
+
+    Respiration, physics of natural, 96
+      reflex arrest of, 39
+
+    Respiratory abnormalities, minor, 39
+      major, 141
+
+    Respiratory system, effects of ether upon, 76
+      after-effects of anæsthetics upon, 150
+
+    Rigidity of muscles in asphyxia, 19, 38, 39
+      in second stage, 33
+
+
+               S
+
+    Saline injections, per rectus, 42
+      subcutaneous, 14
+
+    Schimmelbusch’s mask, 28, 116
+
+    Scopolamine, 44, 103
+
+    Secondary syncope, 17, 138, 143
+
+    Secretion of mucus, 40, 76
+      of urine, 168
+
+    Sedatives, 12, 42
+
+    Selection of anæsthetic, 162
+
+    Semi-open method, 28
+
+    Septic cases, 9, 60, 156, 168
+
+    Sequelæ of anæsthesia, 100
+
+    Sex, relation to anæsthesia, 165
+
+    Shipway, Dr, 91, 101
+
+    Shock, 5
+      difference between syncope and, 142
+
+    Short, Mr Rendle, 154
+
+    Sickness (_see_ Vomiting)
+
+    Sighing, 40
+
+    Sight-feed machines for gas-oxygen, 70
+
+    Signs of anæsthesia, 36, 53, 65
+
+    Silk, Dr J. W., 23, 87
+
+    Single dose anæsthetics, 30, 163
+
+    Sitting posture, 21, 158
+
+    Slow respiration, 39
+
+    Spasm, muscular, 19
+      of jaw muscles, 15
+      of larynx, 16, 26, 169
+
+    Specific gravity of chloroform, 109
+      of ether, 74
+
+    Spinal anæsthesia, 193
+
+    Stages of anæsthesia, 31
+
+    Starvation, a cause of shock, 9
+      of acidosis, 155
+
+    Status lymphaticus, 148
+
+    Stertor, 40, 53
+
+    Stimuli from field of operations, 6
+
+    Stomach tube, before operation, 141
+
+    Stovaine, 173
+
+    Stridor, 16, 26, 40
+
+    Struggling, 34
+
+    Strychnine, 147
+
+    Subcutaneous saline, 14
+
+    Swallowing, movements of, 33
+
+    Sylvester’s method of artificial respiration, 146
+
+    Syncope, 142
+
+    Syringe for local anæsthesia, 176
+      for spinal anæsthesia, 176
+
+
+               T
+
+    Teeth, danger of dropping of into larynx, 16
+      extraction of, 54, 57, 128, 131, 163
+
+    Teter, Dr., on nitrous oxide and oxygen, 68
+
+    Thomson, Prof. Alexis, 12, 158
+
+    Thomson, Torrance, on intratracheal anæsthesia, 96
+
+    Thoracic operations, local anæsthesia in, 186
+
+    Three-way tap for nitrous oxide, 50, 128
+
+    Thyroid gland, _see_ Goitre
+
+    Time for operations, 42
+
+    Time afforded by single dose anæsthetics, 163
+
+    Tongue falling back of, 16
+      forceps for, 24
+      operations upon, 97, 118, 166
+      local anæsthesia for, 191
+
+    Tonsils and adenoids, 127, 166
+
+    Trachea, mucus in, 40
+      pressure upon, 17
+
+    Trachetomy, 142, 185
+
+    Tremor, ether, 38
+
+    Trendelenberg posture, 158
+
+    Tropacocaine, 173
+
+    Turner, Dr Logan, 125
+
+
+               U
+
+    Urine, secretion of prevented by morphia, 168
+
+
+               V
+
+    Vagus nerve, 110, 145
+
+    Valved method, features of, 29
+
+    Vapour method, ether, 90
+      ethyl chloride, 125
+
+    Vaso-motor system, in shock, 9
+      in asphyxia, 17
+      in nitrous oxide, 46 (and _see_ Physiology)
+
+    Veins, large, emptying into heart, 10
+      engorgement of, 20, 151
+
+    Venesection in syncope, 147
+
+    Veronal, 12
+
+    Vicious circle of asphyxia, 20
+
+    Vital medullary centres, 3
+
+    Vomiting, 140, 152
+      impending, 39, 141
+
+
+               W
+
+    War, anti-shock, measures in, 11
+      lessons of, 61, 151
+
+    Warming anæsthetic vapours, 62, 90, 101
+
+    Wedge for opening clenched jaws, 25
+
+    Withdrawal of anæsthetic, for stridor, 26
+      for breath holding and struggling, 34
+      for syncope, 145
+
+
+FOOTNOTES:
+
+[1] This can be done to a very limited extent indeed if the ordinary
+valves here described are used. _See_ page 68.
+
+[2] A safeguard provided on some machines is a side lead from the
+oxygen supply direct to the facepiece whereby pure oxygen can be given
+if required.
+
+[3] The amount of oxygen in a cylinder is designated in terms of cubic
+feet. A cylinder which would hold 100 gallons of N_{2}O, will contain
+30 cubic feet of oxygen.
+
+[4] In the figure the Clover is shown with gas valves and 2-gallon bag,
+arranged for “gas and ether.”
+
+[5] Trans. xvii. Internat. Med. Cong. Sub-sect. (vii.) Part i.
+
+[6] _Journal_ Amer. Med. Assoc., Sept. 1913.
+
+[7] Trans. xvii., Internat. Med. Cong. Sub-sec. (vii.), Part i.
+
+[8] Trans. xvii., Internat. Med. Cong., Sub-sec. (vii.), Part ii.
+
+[9] Trans. xvii., Internat. Med. Cong., Sub-sec. (vii.), Part I.
+
+[10] The student should be careful to be sure that the bulb is attached
+to the _inlet pipe_: if by accident it be slipped on to the outlet
+pipe, the first compression of the bulb will eject a stream of liquid
+chloroform from the instrument.
+
+[11] The author described this method in a paper read before the
+Scottish Branch of the British Dental Association, and afterwards
+published in the _Journal_ of the Association under the title “The
+Edinburgh System of Dental Anæsthesia.” To the use of this term Dr J.
+H. Gibbs, of Edinburgh, took strong exception in a letter to the Editor
+of the _Journal_. The author has and had no desire to convey the
+impression that this system was universally used in Edinburgh, but
+simply that it is the method taught by Dr Guy, Dean of the School, to
+the students in the Extraction Room.
+
+
+Transcriber’s Notes:
+
+1. Obvious printers’, punctuation and spelling errors have been
+corrected silently.
+
+2. Where hyphenation is in doubt, it has been retained as in the
+original.
+
+3. Some hyphenated and non-hyphenated versions of the same words have
+been retained as in the original.
+
+4. Superscripts are represented using the caret character, e.g. D^r. or
+X^{xx}.
+
+5. Italics are shown as _xxx_.
+
+6. Bold print is shown as =xxx=.
+
+
+
+*** END OF THE PROJECT GUTENBERG EBOOK 75985 ***
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+<body>
+<div style='text-align:center'>*** START OF THE PROJECT GUTENBERG EBOOK 75985 ***</div>
+
+
+<h1>HANDBOOK OF<br>
+<span class="gesperrt">ANÆSTHETICS</span></h1>
+
+<p class="center p2 xs">BY</p>
+
+<p class="center">J. STUART ROSS, M.B., <span class="smcap">Ch.B.</span>, F.R.C.S.E.</p>
+
+<p class="center xs">LECTURER IN PRACTICAL ANÆSTHETICS, UNIVERSITY OF EDINBURGH;<br>
+HONORARY ANÆSTHETIST EDINBURGH DENTAL SCHOOL;<br>
+ANÆSTHETIST, DEACONESS HOSPITAL; INSTRUCTOR<br>
+IN ANÆSTHETICS, EDIN. ROYAL INFIRMARY</p>
+
+<p class="center p2 lg">With an Introduction</p>
+
+<p class="center xs">BY</p>
+
+<p class="center">HY. ALEXIS THOMSON, C.M.G., M.D., F.R.C.S.E.</p>
+
+<p class="center xs">PROFESSOR OF SURGERY, UNIVERSITY OF EDINBURGH</p>
+
+<p class="center sm p1">AND CHAPTERS UPON</p>
+
+<p class="center lg">Local and Spinal Anæsthesia</p>
+
+<p class="center xs">BY</p>
+
+<p class="center">WM. QUARRY WOOD, M.D., F.R.C.S.E.</p>
+
+<p class="center xs">LATELY TEMPORARY ASSISTANT SURGEON, EDINBURGH ROYAL INFIRMARY</p>
+
+<p class="center sm p1">AND UPON</p>
+
+<p class="center lg">Intratracheal Anæsthesia</p>
+
+<p class="center xs">BY</p>
+
+<p class="center">H. TORRANCE THOMSON, M.D., F.R.C.S.E.</p>
+
+<p class="center xs">ANÆSTHETIST TO THE LEITH HOSPITAL</p>
+
+<p class="center p4 sm">EDINBURGH<br>
+E. &amp; S. LIVINGSTONE, 17 TEVIOT PLACE<br>
+1919</p>
+
+<div class="chapter">
+<h2>CONTENTS</h2>
+</div>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <th class="chap">CHAP.</th>
+    <th></th>
+    <th class="pag">PAGE</th>
+  </tr>
+
+   <tr>
+    <td class="chn"></td>
+    <td class="cht smcap">Introduction by Professor Alexis Thomson</td>
+    <td class="pag"><a href="#Page_ix">ix</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn"></td>
+    <td class="cht smcap">Preface</td>
+    <td class="pag"><a href="#Page_xi">xi</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">I.</td>
+    <td class="cht smcap">Physiological Action of Anæsthetic Drugs</td>
+    <td class="pag"><a href="#Page_1">1</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">II.</td>
+    <td class="cht smcap">Shock and Anæsthesia</td>
+    <td class="pag"><a href="#Page_5">5</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">III.</td>
+    <td class="cht smcap">Asphyxia or Anoxæmia</td>
+    <td class="pag"><a href="#Page_15">15</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">IV.</td>
+    <td class="cht smcap">Methods of Anæsthetising</td>
+    <td class="pag"><a href="#Page_28">28</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">V.</td>
+    <td class="cht smcap">The Clinical Observation of the Patient</td>
+    <td class="pag"><a href="#Page_31">31</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">VI.</td>
+    <td class="cht smcap">The Preparation of the Patient</td>
+    <td class="pag"><a href="#Page_42">42</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">VII.</td>
+    <td class="cht smcap">Nitrous Oxide</td>
+    <td class="pag"><a href="#Page_46">46</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">VIII.</td>
+    <td class="cht smcap">Nitrous Oxide and Oxygen</td>
+    <td class="pag"><a href="#Page_60">60</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">IX.</td>
+    <td class="cht smcap">Ether</td>
+    <td class="pag"><a href="#Page_74">74</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">X.</td>
+    <td class="cht smcap">Intratracheal Ether</td>
+    <td class="pag"><a href="#Page_96">96</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XI.</td>
+    <td class="cht smcap">Chloroform</td>
+    <td class="pag"><a href="#Page_109">109</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XII.</td>
+    <td class="cht smcap">Ethyl Chloride</td>
+    <td class="pag"><a href="#Page_122">122</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XIII.</td>
+    <td class="cht smcap">Mixtures of Nitrous Oxide and Ethyl Chloride</td>
+    <td class="pag"><a href="#Page_128">128</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XIV.</td>
+    <td class="cht smcap">Mixtures of Chloroform and Ether</td>
+    <td class="pag"><a href="#Page_134">134</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XV.</td>
+    <td class="cht smcap">Sequences</td>
+    <td class="pag"><a href="#Page_137">137</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XVI.</td>
+    <td class="cht smcap">The Accidents of Anæsthesia</td>
+    <td class="pag"><a href="#Page_140">140</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XVII.</td>
+    <td class="cht smcap">The Sequelæ of Anæsthesia</td>
+    <td class="pag"><a href="#Page_151">151</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XVIII.</td>
+    <td class="cht smcap">Posture of the Patient</td>
+    <td class="pag"><a href="#Page_157">157</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XIX.</td>
+    <td class="cht smcap">The Choice of the Anæsthetic</td>
+    <td class="pag"><a href="#Page_162">162</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XX.</td>
+    <td class="cht smcap">Local Anæsthesia</td>
+    <td class="pag"><a href="#Page_171">171</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn">XXI.</td>
+    <td class="cht smcap">Spinal Anæsthesia</td>
+    <td class="pag"><a href="#Page_193">193</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn"></td>
+    <td class="cht smcap">Appendix</td>
+    <td class="pag"><a href="#Page_201">201</a></td>
+  </tr>
+
+   <tr>
+    <td class="chn"></td>
+    <td class="cht smcap">Index</td>
+    <td class="pag"><a href="#Page_209">209</a></td>
+  </tr>
+</table>
+
+<div class="chapter">
+<h2>LIST OF ILLUSTRATIONS.</h2>
+</div>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <th class="chap">FIG.</th>
+    <th></th>
+    <th class="pag">PAGE.</th>
+  </tr>
+
+  <tr>
+    <td class="chn">1.</td>
+    <td class="cht">Shock (Grey and Parsons)</td>
+    <td class="pag"><a href="#i_p006">6</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">2.</td>
+    <td class="cht">Shock (after Crile)</td>
+    <td class="pag"><a href="#i_p008">8</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">3.</td>
+    <td class="cht">Diagram to Illustrate Anoci-Association (after Crile)</td>
+    <td class="pag"><a href="#i_p011">11</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">4.</td>
+    <td class="cht">Apparatus for Lane’s Saline Infusion</td>
+    <td class="pag"><a href="#i_p013">13</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">5.</td>
+    <td class="cht">Diagram of the Vicious Circle of Asphyxia</td>
+    <td class="pag"><a href="#i_p020">20</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">6.</td>
+    <td class="cht">Hewitt’s Mouth Props</td>
+    <td class="pag"><a href="#i_p022">22</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">7.</td>
+    <td class="cht">Bellamy Gardner’s Mouth Props</td>
+    <td class="pag"><a href="#i_p023a">23</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">8.</td>
+    <td class="cht">Phillips’ Modification of Hewitt’s Artificial Air-way</td>
+    <td class="pag"><a href="#i_p023b">23</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">9.</td>
+    <td class="cht">Silk’s Nasal Tubes</td>
+    <td class="pag"><a href="#i_p023c">23</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">10.</td>
+    <td class="cht">Tongue Forceps and Glossotilt</td>
+    <td class="pag"><a href="#i_p024a">24</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">11.</td>
+    <td class="cht">Apparatus for Opening Clenched Jaws</td>
+    <td class="pag"><a href="#i_p025a">25</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">12.</td>
+    <td class="cht">Frame for Adapting Vertical Cylinders to Foot Use</td>
+    <td class="pag"><a href="#i_p047">47</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">13.</td>
+    <td class="cht">Nitrous Oxide Cylinders (upright and angle)</td>
+    <td class="pag"><a href="#i_p048">48</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">14.</td>
+    <td class="cht">Complete Nitrous Oxide Apparatus</td>
+    <td class="pag"><a href="#i_p049">49</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">15.</td>
+    <td class="cht">Barth 3-way Nitrous Oxide Tap</td>
+    <td class="pag"><a href="#i_p050a">50</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">16.</td>
+    <td class="cht">Hewitt’s Wide-bore Nitrous Oxide Valves</td>
+    <td class="pag"><a href="#i_p050b">50</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">17.</td>
+    <td class="cht">Ash’s Modification of Paterson’s Nasal Gas</td>
+    <td class="pag"><a href="#i_p058">58</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">18.</td>
+    <td class="cht">Hewitt’s Apparatus for Nitrous Oxide and Oxygen</td>
+    <td class="pag"><a href="#i_p063">63</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">19.</td>
+    <td class="cht">Diagram to Illustrate Action of Hewitt’s and Teter’s Gas-Oxygen
+Methods</td>
+    <td class="pag"><a href="#i_p067">67</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">20.</td>
+    <td class="cht">Details of Clark’s Expiratory Valve</td>
+    <td class="pag"><a href="#i_p068">68</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">21.</td>
+    <td class="cht">The Clarke Gas-oxygen Apparatus</td>
+    <td class="pag"><a href="#i_p069">69</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">22.</td>
+    <td class="cht">Marshall’s Sight-feed Gas-oxygen Apparatus</td>
+    <td class="pag"><a href="#i_p070">70</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">23.</td>
+    <td class="cht">Clover’s Ether Inhaler, with Nitrous Oxide Attachment</td>
+    <td class="pag"><a href="#i_p077">77</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">24.</td>
+    <td class="cht">Clover’s Inhaler, Diagram of a Vertical Section</td>
+    <td class="pag"><a href="#i_p078">78</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">25.</td>
+    <td class="cht">Hewitt’s Wide-bore Ether Inhaler</td>
+    <td class="pag"><a href="#i_p080">80</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">26.</td>
+    <td class="cht">Ormsby’s Ether Inhaler</td>
+    <td class="pag"><a href="#i_p081">81</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">27.</td>
+    <td class="cht">Bellamy Gardner’s Mask and Ether Dropper</td>
+    <td class="pag"><a href="#i_p083">83</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">28.</td>
+    <td class="cht">Four Photographs to Illustrate the Administration of Open
+Ether</td>
+    <td class="pag"><a href="#i_p084a">84–5</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">29.</td>
+    <td class="cht">Shipway’s Warmed Ether Apparatus</td>
+    <td class="pag"><a href="#i_p091">91</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">30.</td>
+    <td class="cht">Diagram of Intratracheal Apparatus</td>
+    <td class="pag"><a href="#i_p098">98</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">31.</td>
+    <td class="cht">Electric Blower for Intratracheal Method</td>
+    <td class="pag"><a href="#i_p099">99</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">32.</td>
+    <td class="cht">Kelly’s Intratracheal Apparatus</td>
+    <td class="pag"><a href="#i_p100">100</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">33.</td>
+    <td class="cht">Shipway’s Intratracheal Apparatus</td>
+    <td class="pag"><a href="#i_p102">102</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">34.</td>
+    <td class="cht">Hill’s Direct Laryngoscope</td>
+    <td class="pag"><a href="#i_p104">104</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">35.</td>
+    <td class="cht">Diagram of Blood-pressure Curves Obtainable with Chloroform</td>
+    <td class="pag"><a href="#i_p110">110</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">36.</td>
+    <td class="cht">Vernon Harcourt’s Percentage Chloroform Inhaler</td>
+    <td class="pag"><a href="#i_p115">115</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">37.</td>
+    <td class="cht">Chloroform Mask</td>
+    <td class="pag"><a href="#i_p116">116</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">38.</td>
+    <td class="cht">Chloroform Drop Bottles</td>
+    <td class="pag"><a href="#i_p117">117</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">39.</td>
+    <td class="cht">Junker’s Chloroform Apparatus</td>
+    <td class="pag"><a href="#i_p119">119</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">40.</td>
+    <td class="cht">Tube of Ethyl-Chloride</td>
+    <td class="pag"><a href="#i_p122">122</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">41.</td>
+    <td class="cht">Ethyl-Chloride Inhaler</td>
+    <td class="pag"><a href="#i_p124">124</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">42.</td>
+    <td class="cht">Guy’s Gas and Ethyl-Chloride Inhaler</td>
+    <td class="pag"><a href="#i_p128">128</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">43.</td>
+    <td class="cht">Details of Guy’s Inhaler</td>
+    <td class="pag"><a href="#i_p129">129</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">44.</td>
+    <td class="cht">Diagram of Gas-Oxygen Method Introduced by Dr Guy and the Author</td>
+    <td class="pag"><a href="#i_p130">130</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">45.</td>
+    <td class="cht">The Guy Ross Gas-Oxygen Instrument</td>
+    <td class="pag"><a href="#i_p131">131</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">46.</td>
+    <td class="cht">Rendle’s Cone</td>
+    <td class="pag"><a href="#i_p135">135</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">47.</td>
+    <td class="cht">Clover Inhaler adapted for the Ethyl Chloride-Ether Sequence</td>
+    <td class="pag"><a href="#i_p139">139</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">48.</td>
+    <td class="cht">Two Photographs illustrating Sylvester’s Artificial Respiration</td>
+    <td class="pag"><a href="#i_p146">146–7</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">49.</td>
+    <td class="cht">Sitting-up Posture for Operations upon the Head and Neck</td>
+    <td class="pag"><a href="#i_p159">159</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">50.</td>
+    <td class="cht">O’Malley’s Posture for Intra-nasal Surgery</td>
+    <td class="pag"><a href="#i_p160">160</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">51.</td>
+    <td class="cht">All-metal Syringe for Infiltration Anæsthesia</td>
+    <td class="pag"><a href="#i_p176">176</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">52.</td>
+    <td class="cht">Infiltration of the Brachial Plexus</td>
+    <td class="pag"><a href="#i_p183">183</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">53.</td>
+    <td class="cht">Needle and Syringe for Spinal Analgesia</td>
+    <td class="pag"><a href="#i_p194">194</a></td>
+  </tr>
+
+  <tr>
+    <td class="chn">54.</td>
+    <td class="cht">Position of the Patient for Spinal Analgesia</td>
+    <td class="pag"><a href="#i_p196">196</a></td>
+  </tr>
+</table>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_ix">[ix]</span></p>
+
+<h2>INTRODUCTION.</h2>
+</div>
+
+
+<p>The securing of a safe anæsthesia during operations is more important
+than ever before, partly because of the mere number of operations,
+and partly because of the greater extent to which other operative
+risks—hæmorrhage, shock and infection—have been overcome. The risk
+from the anæsthetic is now so very small that the joint aim of the
+surgeon and anæsthetist to abolish it altogether is not far from
+being accomplished. The author of this volume has done a good deal to
+accomplish this end, and it is a matter of congratulation that he has
+now published an account of his methods, so that a larger circle may
+benefit from his teaching and his experience.</p>
+
+<p>The author very properly goes further and maintains that anæsthesia
+must not only be safe but must also be good; good anæsthesia is
+absolutely vital to good surgery. Only a generation back many surgeons
+professed to see no difference as to who gave the anæsthetic; at the
+present day no one willingly embarks upon a difficult operation without
+the aid of a skilled anæsthetist.</p>
+
+<p>In various parts of the book the author has very rightly laid great
+emphasis upon the influence which the work of the surgeon has upon
+that of the anæsthetist. The latter may learn much from an occasional
+glance at the field of operation. He should not interest himself in the
+details of operative procedure to the distraction of his mind from his
+own responsibilities; but he can, in abdominal surgery, see for himself
+whether the muscles<span class="pagenum" id="Page_x">[x]</span> are properly relaxed, and observe the state of
+operation, so that he can when necessary deepen the anæsthesia in good
+time, while not maintaining deep anæsthesia when a light one would
+suffice. Finally, he can check his other sources of information as to
+the condition of the circulation by noticing the force with which cut
+arteries spout, the colour of the blood and the size of uncut veins.</p>
+
+<p>Like other branches of medicine, adequate study as well as practical
+experience is required in order to master the art of administering
+anæsthetics, and that a reliable manual of instruction is essential,
+goes without saying; I feel on perfectly safe ground in recommending
+this book as such both to the student and the practitioner.</p>
+
+<p class="r2 p-min">ALEXIS THOMSON.</p>
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_xi">[xi]</span></p>
+
+<h2>PREFACE.</h2>
+</div>
+
+
+<p>This little book is an attempt to present to the student and
+practitioner a condensed account of modern anæsthetic views and
+practice. In choosing a general scheme I have tried to lay emphasis
+upon the relation of anæsthesia to general medical science rather than
+upon elaborate descriptions of anæsthetic apparatus and methods which
+a few years hence may be superseded. I have therefore devoted the
+first four chapters to an account of the various forces which modify
+the physiology of the patient during an operation under a general
+anæsthetic, in so far as we at present understand them. I trust that
+they will prove not only a sound basis for the information given in
+the rest of the book but also a help towards forming a judgment upon
+new methods and appliances as and when they meet the attention of the
+reader.</p>
+
+<p>In making a selection of drugs and appliances for description, I have
+eliminated those which do not appear to me to have any real sphere of
+usefulness.</p>
+
+<p>The account of nitrous oxide and oxygen has been given in some
+detail. Both the profession and the lay public have arrived, through
+the experiences of the war, at a more just appreciation of the
+possibilities of this combination than was at all general before
+the year 1914. At the present day, no one who proposes to engage in
+anæsthetic work can afford to remain unpractised in its administration.</p>
+
+<p>I have an apology to make to my women readers. Throughout the book,
+when speaking of the anæsthetist, I have presumed the male sex. Such
+phrases as “his or her” and “he or she” are tedious and inelegant, and
+their omission must not be taken as<span class="pagenum" id="Page_xii">[xii]</span> forgetfulness on the author’s part
+that women frequently make very good anæsthetists.</p>
+
+<p>Professor Alexis Thomson has added to the many kindnesses I have
+received at his hands by writing the Introduction which immediately
+precedes this Preface, and I wish to express my sincere thanks to him
+for such a valuable addition to the book.</p>
+
+<p>From Mr David Wallace, F.R.C.S.E., I have received much valuable help
+and guidance in anæsthetic matters. It was largely due to his kindly
+assistance and moral support that I was encouraged to persevere with my
+early attempts to use nitrous oxide and oxygen in major surgery. The
+hints which are given in connection with Genito-Urinary Surgery are
+also derived from him.</p>
+
+<p>The chapters upon Local and Spinal Anæsthesia are entirely the work of
+Mr Wood, to whom I must express my gratitude for the admirable way in
+which he has done the work.</p>
+
+<p>I must also thank Dr Torrance Thomson most sincerely for his useful
+contribution in chapter <span class="allsmcap">X</span>, which constitutes a complete
+monograph upon Intratracheal Anæsthesia.</p>
+
+<p>To Dr Wm. Guy I am indebted for the photographs which appear in the
+book, and I must express my sincere gratitude to him for the trouble he
+has taken in the matter.</p>
+
+<p>Much thanks are also due to the following firms who have been kind
+enough to lend illustrative blocks:—Messrs Claudius Ash &amp; Co. Ltd., G.
+Barth &amp; Co., De Trey &amp; Co., J. Gardner &amp; Son, Allen &amp; Hanbury’s Ltd.,
+Meyer &amp; Phelps, Coxeter &amp; Son, Down Bros., Ltd., Krohne &amp; Sesemann, and
+Mr J. H. Montague.</p>
+
+<p>Lastly, I must express my high appreciation of the courtesy which the
+publishers have shown to me, and of their generosity in the matter of
+illustrations.</p>
+
+<p class="r2 p-min">J. STUART ROSS.</p>
+
+<p class="sm p-min"><i>October 1919.</i></p>
+
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_1">[1]</span></p>
+
+<p class="center xl"><b>Handbook of Anæsthetics.</b></p>
+</div>
+
+<h2>CHAPTER I.<br>
+<span class="subhed"><b>PHYSIOLOGICAL ACTION OF ANÆSTHETIC DRUGS.</b></span></h2>
+
+<p>Every anæsthetic drug has certain pharmacological peculiarities of its
+own, but all have much in common, and it is to these common features we
+shall first direct our attention.</p>
+
+<p>Reaching the blood stream by absorption from the lung alveoli, the drug
+enters into loose combination with the red blood corpuscles; a small
+proportion only is carried in the plasma. Within the corpuscles it
+must of necessity displace a certain proportion of the oxygen normally
+carried: this factor is of great importance only in the case of nitrous
+oxide gas, which readily displaces the larger part of the normal oxygen
+content. In the case of other anæsthetics, the same process occurs; but
+to a less extent. Detailed figures of the extent to which the blood
+gases are altered in various stages of chloroform anæsthesia will be
+found in Appendix III.</p>
+
+<p>The actions of individual drugs upon the circulatory, respiratory,
+and excretory systems differ so considerably that a small section
+has been devoted to this subject in each of the chapters devoted to
+nitrous oxide, ether, and chloroform respectively. One feature is,
+however, dependent upon the <i>state of anæsthesia</i> rather<span class="pagenum" id="Page_2">[2]</span> than
+the action of the particular drug, and that is a certain slight fall
+of blood pressure. This phenomenon is seen even in natural sleep, and
+is presumably due simply to lack of normal stimuli such as tactile,
+visual, and auditory impressions which in the ordinary circumstances of
+life, help to maintain the tone of the vasomotor system. That such a
+fall is due to the <i>state</i> of anæsthesia admits of little doubt,
+but the fact is not always easy to demonstrate since each of the drugs
+themselves have a marked influence upon the B.P., which masks the pure
+effect of the anæsthetic sleep.</p>
+
+
+<h3><b>Action upon the Nervous System.</b></h3>
+
+<p>It is in this system, of course, that we look for the characteristic
+action of anæsthetics, since if we had a choice, it is the brain
+only which we should desire to influence by our drug. It used to be
+said that anæsthetics paralyse the brain from above downwards, but
+that is only approximately true. More correctly we may say that the
+more highly developed parts of the brain are earliest affected, and
+that those portions, such as the vital medullary centres, which man
+shares in common with his humbler zoological relatives, maintain
+their activity until the last. Moreover, it must be remembered that
+before any brain centre succumbs, it passes through a preliminary
+stage of <i>excitement</i>, varying in intensity with varying drugs
+and also with different types of patients. Those who are accustomed
+to administer to their nervous centres repeated large doses of such
+nerve poisons as alcohol and tobacco, may show very evident signs of
+this preliminary cerebral irritation during the process of induction
+of anæsthesia; so do also the unhappy possessors of nervous systems
+deranged from other causes such as epilepsy.</p>
+
+<p><i>The first centres to be attacked are those of thought and
+perception.</i> The patient is incapable of coherent reasoning, and
+loses touch to some extent with impressions from the outside world.
+<i>Muscular sense and co-ordination next become affected.</i><span class="pagenum" id="Page_3">[3]</span> Although
+still able to move the limbs or the head, movements are incoherent, and
+if at this stage the patient were put upon his feet, he would stagger
+as he does in alcoholic intoxication. By this time <i>sensation</i>,
+both tactile and special, begins to be affected. The patient is no
+longer cognisant of pain,—if cut he would at any rate not have a
+remembrance of pain. <i>The special senses</i> are at this stage also
+lost, one of the last to go being the auditory sense, a point which
+is sometimes forgotten by those inclined to talk while anæsthesia is
+being induced. <i>Muscle tone is the next function</i> to be lost, and
+at this stage all movements on the part of the patient should cease
+except those of respiration. <i>The reflexes</i> disappear at varying
+stages: the spinal reflexes, <i>e.g.</i> the knee-jerks, disappear
+fairly early, probably before muscle tone is entirely abolished, but
+certain other reflexes persist to a later stage. Those which are of
+most interest to the anæsthetist are the conjunctival, corneal, and
+pupillary reflexes of which he will find full details in Chapter
+<span class="allsmcap">V</span>.</p>
+
+<p>Lastly the <i>vital medullary centres</i>, respiratory, vasomotor,
+and cardiac are overcome, and at this stage we have passed beyond the
+stage of a proper anæsthesia into that of over-dosage. In passing it
+may be observed that the level at which one endeavours to work is that
+indicated by the loss of muscle tone and of some of the reflexes and
+the full activity of the medullary centres, and that an anæsthetic is
+good or bad according as it gives a wide or narrow margin between these
+two events.</p>
+
+<p>Upon the <i>peripheral nerves</i>, anæsthetics have much less effect
+than on the central nervous system. Faradisation of a <i>motor
+nerve</i> will in the deepest anæsthesia still cause immediate
+contraction of the muscles supplied by it, showing that the
+conductivity of the nerve is unaffected. Of far more importance,
+however, is the fact that the <i>sensory nerves</i> are not paralysed.
+That pain is not felt by the patient is due simply to the loss of
+function of the cerebral sensory centres; <i>injury to the nerve
+still causes an impulse to be<span class="pagenum" id="Page_4">[4]</span> transmitted to the brain</i>. Since no
+operative procedure can be carried out without more or less trauma
+(injury) to sensory nerves, we may picture the brain of the patient
+undergoing a surgical operation while under a general anæsthetic,
+as being constantly bombarded by sensory stimuli, which though not
+consciously appreciated by the sleeping patient, are yet capable of
+producing reflex effects of a definite character, the importance of
+which to the work of the surgeon and anæsthetist it is difficult to
+exaggerate, and of which a condensed account will be found in the
+succeeding chapter.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_5">[5]</span></p>
+
+<h2>CHAPTER II.<br>
+<span class="subhed"><b>SHOCK AND ANÆSTHESIA.</b></span></h2></div>
+
+<p>Under this short and convenient title, the author proposes to discuss
+all the changes observable in the patient’s condition, the causation
+of which can be traced to the procedure of the surgeon. The use of
+the term <i>shock</i> was at one time, and by some teachers still is,
+restricted to a definite clinical condition. The patient was described
+as lying pallid and almost pulseless, with dilated pupils, cold
+sweating skin, and gasping, irregular respirations. In the view more
+generally taken to-day, that is but the extreme and final manifestation
+of a syndrome, which any patient who suffers trauma (whether inflicted
+accidentally or by the surgeon) exhibits in a greater or less degree,
+and from which general anæsthesia protects a patient to a very limited
+extent only.</p>
+
+<p>Professor Crile, to whose work we owe so much of our knowledge on this
+subject, has said, “In general anæsthesia, part of the brain only is
+asleep.” Though consciousness is abolished, many parts of the brain
+are quite capable of responding to <i>centripetal impulses</i> passed
+to the brain through sensory nerves injured by the knife. A full
+account of the changes demonstrated by Crile in some of the cells of
+the grey matter of the brain as a result of such stimuli, and of the
+interpretation put upon these by their discoverer, is not suitable
+for a text-book of anæsthesia. It is sufficient to say that such
+changes have been discovered, and that their occurrence as a result
+of trauma is not prevented by inhalational anæsthesia. Such changes,
+though of the utmost interest scientifically, cannot be demonstrated
+clinically, and it is<span class="pagenum" id="Page_6">[6]</span> to alterations of <i>blood pressure</i> and
+of <i>respiration</i> that we must look for clinical evidence of the
+effects of <i>shock stimuli</i>.</p>
+
+  <div class="figcenter" id="i_p006" style="max-width: 473px">
+     <img
+    class="p1"   
+    src="images/i_p006.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 1.</span>—Shock—Blood pressure of a dog undergoing
+laminectomy under general anæsthesia (Grey and Parsons.)</p>
+     <p class="p0 center smaller">(<i>Reproduced by kind permission of the Authors.</i>)</p>
+     </div>
+
+<p>With every incision by the surgeon, sensory nerve twigs are of
+necessity injured. The fibres found in sensory nerves are, it will
+be remembered, either pressor, or depressor—that is, stimulation of
+them, causes either an increase or decrease of the blood pressure,
+the depth and frequency of respiration being usually affected in the
+same direction as the B.P. That such changes do commonly occur is
+easily recognised by clinical observation. The veriest beginner in
+anæsthesia soon learns to expect a deeper, quicker respiration and a
+stronger pulse as soon as the operation has begun. These changes have
+been studied experimentally upon animals and upon the human subject by
+the use of the sphygmomanometer: Fig. 1, drawn from Grey &amp; Parson’s
+Arris and Gale Lectures of 1912,<span class="pagenum" id="Page_7">[7]</span> shows a tracing from a dog undergoing
+laminectomy under general anæsthesia, and gives a good idea of the
+early evidences of shock.</p>
+
+<hr class="tb">
+
+<p>We may condense the results of much work on this subject under the
+following headings:—</p>
+
+<div class="blockquot">
+
+<p>(<i>a</i>) Most stimuli from the field of operation cause a
+sharp rise of blood pressure, followed by a sharp fall.</p>
+
+<p>(<i>b</i>) Successive stimuli delivered quickly one after
+another add their effects together, the total result being
+considerably greater than from one severe trauma.</p>
+
+<p>(<i>c</i>) After a time, the pressor effect of stimuli begins
+to lessen: the animal or patient “wears out,” and finally no
+pressor result can be obtained by the most massive stimulation:
+the curve of B.P. steadily falls: the condition of full surgical
+shock is produced.</p>
+
+<p>(<i>d</i>) The tearing or pulling of tissues produces more
+powerful stimuli than the use of a sharp knife, and, therefore,
+brings on the full condition of shock more rapidly.</p>
+
+<p>(<i>e</i>) Stimuli from some tissues cause much more reflex
+effect upon the organism than from other less sensitive
+structures. This is well exemplified when an abdominal section
+is in progress. Incision of skin causes immediate response in
+deepened respiration and higher B.P.: division of the fascia
+very little effect. If the muscle is divided by the knife, again
+little reflex effect is noticeable, but if it be stretched and
+split by the fingers, the response is powerful. The parietal
+peritoneum, however delicately handled, is one of the most
+sensitive structures in the body, and, unless the patient is
+fully under at the stage either of opening or closing this
+layer, actual breath-holding or straining will occur. On the
+other hand, incision or suture of the hollow viscera will cause
+practically no response however light the anæsthesia, provided<span class="pagenum" id="Page_8">[8]</span>
+these structures, and their connections with the parietes, are
+not pulled upon.</p>
+
+<p>(<i>f</i>) Stimulation of certain selected areas, of which the
+spermatic cord is a well-known but by no means the only example,
+results in an almost immediate fall of blood pressure with
+little or no preliminary rise. In the operating theatre, we
+sometimes see faintness or syncope arising quite suddenly during
+operations in such regions. This subject is explained more fully
+in Chapter <span class="allsmcap">XVI.</span> under the term “Reflex Syncope.”</p>
+</div>
+
+  <div class="figcenter" id="i_p008" style="max-width: 655px">
+     <img
+    class="p1"   
+    src="images/i_p008.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 2.</span>—Combined blood pressure chart showing
+the average of a number of experiments.—A—Under nitrous
+oxide and oxygen. B—Under ether. At each spot marked
+x, a trauma (burning of the paw) was inflicted. (After
+<span class="smcap">Crile</span>.)</p>
+     </div>
+
+<div class="blockquot">
+
+<p>(<i>g</i>) While no general anæsthetic protects absolutely
+from shock stimuli, some anæsthetics give more protection than
+others. Nitrous oxide is the most effective in this respect,<span class="pagenum" id="Page_9">[9]</span>
+its powers being two and a half times greater than that of
+ether: chloroform is even less effective than ether (<i>see</i>
+Fig. <a href="#i_p008">2</a>).</p>
+
+<p>(<i>h</i>) The claim made by the older generation of surgeons
+that shock could be prevented by the use of a <i>deep</i>
+anæsthesia, and that the occurrence of any “Reflex syncope” was
+always a sign of too light an anæsthesia cannot be made good. At
+the same time, it must be admitted that too light an anæsthesia
+does increase the likelihood of shock. <i>Prolonged deep</i>
+anæsthesia, on the other hand, produces by itself a condition
+indistinguishable from shock, with the single exception of
+nitrous oxide gas.</p>
+
+<p>(<i>i</i>) Operative shock is predisposed to by several factors
+of which the following are the most important:—</p>
+
+<p class="p-indent">1. Hæmorrhage before or during operation.</p>
+
+<p class="p-indent">2. Sepsis.</p>
+
+<p class="p-indent">3. Fear.</p>
+
+<p class="p-indent">4. Prolonged starvation.</p>
+
+<p>5. Certain diseases, especially hyperthyroidism
+(exopthalmic goître).</p>
+</div>
+
+
+<h3><b>Theories of Shock.</b></h3>
+
+<p>So far as we have touched in the above upon theory, it has been theory
+which receives general acceptance and which accords with known clinical
+facts. When we come to discuss <i>the reason why blood-pressure falls
+in shock</i>, we are in more debatable country.</p>
+
+<p>Crile’s original view was that the upstroke seen in such charts as
+shown in Fig. 1 are caused by reflex vaso-constriction, and that the
+final fall of B.P. was due to exhaustion of the vaso-motor centre.
+This view he does not seem to have modified as a result of his later
+discovery of degenerative changes in certain cells of the grey matter
+of the brain.</p>
+
+<p>Other workers, J. D. Malcolm in this country, and Yandell<span class="pagenum" id="Page_10">[10]</span> Henderson,
+of Yale, U.S.A., maintain an opinion diametrically opposite. In their
+view, in fully developed shock, the vessels are in vaso-constriction,
+and the circulation is arrested from undue internal resistance to blood
+flow.</p>
+
+<p>A third explanation of lowered B.P. has been offered, and while its
+significance is not understood, there is fairly general agreement as
+to its validity. This factor is a <i>reduction in the total blood
+volume</i>—an oligæmia. No one has as yet demonstrated to what region
+or organ the missing blood volume has retreated.</p>
+
+
+<h4 class="smcap">Yandell Henderson’s Acapnic theory of Shock.</h4>
+
+<p>Acapnia is a condition in which the CO<sub>2</sub> content of the blood and
+tissues has been brought to too low a level. Those who climb mountains
+suffer from it, and so do those who breathe rapidly and heavily for a
+prolonged period. Carbon dioxide is necessary for the vigour of the
+respiratory centre, of which it may be termed the natural regulator.
+Moreover, the heart and the great veins which empty into it require a
+certain proportion of CO<sub>2</sub> in the blood.</p>
+
+<p>Admittedly, patients inhaling anæsthetics do on occasion breathe too
+deeply. Sometimes they do so voluntarily before losing consciousness,
+sometimes reflexly as a result of such a manœuvre as stretching the
+sphincter ani. Do they thereby bring their CO<sub>2</sub> down to a level which
+does serious harm and which can be considered a cause of collapse under
+anæsthesia? Henderson says they can and do: most other workers deny the
+possibility.</p>
+
+  <div class="figcenter" id="i_p011" style="max-width: 526px">
+     <img
+    class="p1"   
+    src="images/i_p011.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig 3.</span>—Diagram (after <span class="smcap">Crile</span>) to illustrate
+anoci-association. In “A” the trauma is inflicted on the leg,
+and the brain being wholly unprotected, considerable shock
+is suffered. In “B” the brain is protected by inhalational
+anæsthesia from the effects of fear, etc. In “C” the sensory
+nerves from the seat of trauma are blocked by novocaine, and the
+brain also protected by inhalational anæsthesia. Theoretically
+no shock is suffered.</p>
+     </div>
+
+
+<h3><b>Prevention and Treatment of Shock.</b></h3>
+
+<p>There are many theories of shock but only one anti-shock technique
+which will bear examination. Founding upon his own theory, Crile about
+1913 elaborated his <span class="allsmcap">ANOCI-ASSOCIATION</span> method of which the
+following are the leading features (<i>see</i> Fig. <a href="#i_p011">3</a>):—</p>
+
+<p><span class="pagenum" id="Page_11">[11]</span></p>
+
+<div class="blockquot">
+
+<p>(<i>a</i>) <i>Prevention of fear.</i>—Every member of this team
+is taught the all-important art of so dealing with the patient
+that no unnecessary fear is allowed to remain in his mind.
+That art does not consist in endless repetition of the phrase,
+“Do not be frightened,” but rather in each so bearing himself
+or herself before the patient that he may gradually acquire
+the conviction that he is surrounded by careful, kindly, and
+skilful persons who are doing for him what they do for<span class="pagenum" id="Page_12">[12]</span> hundreds
+of others, and doing it with an expectation of his early and
+complete recovery so certain that they do not need to put it
+into words unless definitely questioned. Such an art is not
+acquired in a day, and some unhappy few are so constituted that
+they can never acquire it.</p>
+
+<p>As a further preventative of fear, and also for other reasons
+explained in Chapter vi., the patient receives a dose of morphia
+(⅙th grain, with ¹⁄₁₂₀th grain atropine, hypodermically) three
+quarters of an hour before operation. Some surgeons go further,
+and give a sedative the night before operation. Veronal gr.
+viii. is the favourite prescription of Prof. Alexis Thomson of
+Edinburgh.</p>
+
+<p>(<i>b</i>) The sensory nerves are “blocked” by infiltration
+with novocain. By the systematic use of local in conjunction
+with general anæsthesia, the harmful stimuli from the area of
+operation are prevented from reaching the brain. For the details
+of this measure, the reader is referred to Chapter xx.</p>
+
+<p>(<i>c</i>) The anæsthetic of choice in Crile’s practice is
+nitrous oxide and oxygen (<i>see</i> Chapter vii.).</p>
+</div>
+
+<p>The whole of this technique has not been generally adopted as a
+routine, but nevertheless the teachings of Crile have greatly
+influenced the mind and practice of most surgeons and anæsthetists.
+Traces of that teaching are to be found everywhere in the organisation
+built up during the Great War to save as many as possible of the lives
+of badly smashed men. At no previous time in the history of surgery was
+the problem of shock so pressing, and a brief resumé of the methods
+adopted is here set down, as an example of how shock should be dealt
+with.</p>
+
+  <div class="figcenter" id="i_p013" style="max-width: 299px">
+     <img
+    class="p1"   
+    src="images/i_p013.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 4.</span>—Lane’s apparatus for subcutaneous
+infusion of saline solution.</p>
+     </div>
+
+
+<h3><b>Treatment of Shock among the Casualties of the War.</b></h3>
+
+<p>The first essentials demanded were the most careful organisation,
+the provision of equipment far in advance of most home civilian<span class="pagenum" id="Page_13">[13]</span>
+hospitals, and of surgical teams specially trained to a high level of
+excellence. Upon recovery from the field, the injured man received
+at the <span class="smcap">Advanced Dressing Station</span>, such first aid dressing
+as was necessary, and a substantial dose of <i>morphia</i>. When the
+latter had had time to take effect, the case was passed back to the
+Field Ambulance (where he received his first dose of antitetanic
+serum), and from there to the <span class="smcap">Casualty Clearing Station</span>.
+During every stage of the journey, he received as much <i>warm fluid
+nourishment as possible</i>. Arrived at the C.C.S., the severe case was
+passed first into the <span class="smcap">Resuscitation Ward</span>. This department,<span class="pagenum" id="Page_14">[14]</span>
+under the charge of a specially trained M.O., concentrated largely
+upon two measures—the thorough <i>warming</i> of the patient,
+and the replacing as far as possible of the fluids lost to him by
+hæmorrhage and shock. The warming in many C.C.S.’s was effected by
+electric radiant heat baths. The fluids were replaced either by way of
+infusing blood from another patient, or by the use of <i>gum saline
+solution</i>. Introduced into a vein, the action of this solution
+persists for a much longer period than that of ordinary saline, being
+less easily lost by osmosis through the capillaries into the tissues.
+From the resuscitation ward, the patient passed to the <span class="smcap">Operating
+Theatre</span>. Though the full technique of anoci-association was
+not always possible, the maxims which Crile had sought to inculcate
+into the practice of surgery influenced the work of surgeons and
+anæsthetists very profoundly. Nitrous oxide and oxygen was used for all
+the severely shocked cases, and infiltration with local anæsthetics
+where feasible and necessary.</p>
+
+
+<h3><b>Subcutaneous Infusion of Saline.</b></h3>
+
+<p>For those who do not feel bound to adopt the Crile technique this is a
+simple measure which does much to minimise shock in prolonged abdominal
+operations. Saline infusion into a vein is so rapidly excreted that its
+influence is very fugacious, but if the fluid be introduced under the
+skin during the period of operation it is slowly absorbed as required
+by the blood. Sir Arbuthnot Lane is a strong advocate of this measure.</p>
+
+<p>Fig. 4 shows a suitable apparatus. The needles are thrust into the
+loose areolar tissue under the breast, one on each side, and a pint or
+more of fluid is <i>slowly</i> run in from the reservoir.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_15">[15]</span></p>
+
+<h2>CHAPTER III.<br>
+<span class="subhed"><b>ASPHYXIA OR ANOXÆMIA.</b></span></h2></div>
+
+<p>Some degree of asphyxia is a common complication of inhalational
+anæsthesia: indeed some small degree of it is almost unavoidable. It
+is hardly too much to say that the difference between a good and a bad
+anæsthetist is that the one recognises and deals with asphyxia in its
+early stages, while the other allows it to assume serious proportions
+before he becomes aware of its existence. The man who only realises
+that asphyxia is present when the patient is deeply cyanosed and has
+ceased to be able to draw any air at all into his chest may know much
+of the physiology of anæsthetic drugs, and be well up in complicated
+anæsthetic apparatus, but knows nothing of the proper practice of
+anæsthesia.</p>
+
+<p>Asphyxia arises during anæsthesia from several causes. In the first
+place, the drug which the patient is inhaling and absorbing into the
+blood, turns out from his red corpuscles a corresponding quantity
+of oxygen. While this is only seen in its extreme form in the case
+of nitrous oxide gas, it is a factor acting even in the case of
+other anæsthetics. Secondly, during deep anæsthesia, the respiratory
+centre may be somewhat depressed, and the force and frequency of the
+respiratory act diminished. Thirdly, the respiratory passages may be
+partially or wholly occluded from <i>mechanical</i> causes. This is far
+the most important type of asphyxia, being the most common, the most
+fatal, and the most easily prevented.</p>
+
+
+<h3><b>Common Causes of Mechanical Asphyxia.</b></h3>
+
+<p>(1) <span class="smcap">Clenching of the Jaws</span> arises not uncommonly during
+anæsthesia, being specially frequent towards the end of the induction<span class="pagenum" id="Page_16">[16]</span>
+period. Since a very large proportion of individuals have nasal
+passages insufficient in bore to carry the full volume of respired air,
+respiration must be obstructed if the jaws are clenched.</p>
+
+<p>(2) <span class="smcap">Falling Back of the Lower Jaw and Base of the Tongue over the
+Epiglottis.</span>—This is always liable to happen after the muscles are
+deeply relaxed.</p>
+
+<p>(3) <span class="smcap">Mucous or Blood or a Foreign Body is Drawn by Inspiration into
+the Air Passages.</span>—Changes of position of the head may release
+mucous which has been gathering in some parts of the mouth or pharynx.
+For instance, if the head has been lying on the side for some time, a
+pool of mucous or saliva commonly gathers in the most dependent cheek,
+and unless this is mopped out before the head is brought into the
+mesial position, this pool will be suddenly tipped backwards, and very
+probably drawn into the larynx. Again, in operations upon the nasal or
+oral cavities, blood is always liable to be inspired, and not a few
+teeth have found their way into the air passages in the practices of
+dental surgeons who do not take precautions against this accident.</p>
+
+<p>(4) <span class="smcap">Spasm of the Adductors of the Vocal Cords</span> is one of the
+most common and most baffling incidents in anæsthesia. It announces
+its presence by the commencement of <i>laryngeal stridor</i>, a
+high-pitched crowing noise, which is as annoying for the surgeon and
+anæsthetist to hear as it is detrimental to the progress of a smooth
+anæsthesia. Inspired mucous or blood almost invariably sets it up, and
+the two conditions of fluid in the larynx and narrowing of the glottis
+from approximation of the cords, add their effects together, with
+resulting obstruction of a high degree.</p>
+
+<p>Laryngeal stridor, however, frequently occurs even when no fluid
+has been inspirated. It may be set up as a reflex from the area
+of operation. Dilatation of the sphincter ani, and removal of the
+prepuce in circumcision, are two common examples of this. It is also
+undoubtedly sometimes caused by giving too strong a vapour<span class="pagenum" id="Page_17">[17]</span> during the
+latter part of the induction stage. Stridor unfortunately sometimes
+occurs from no obvious cause at all, or to speak more correctly, from
+causes which are at present not known to us. It is the author’s belief
+that one of these causes may prove to be <i>morphia</i> given as a
+preliminary to inhalational anæsthesia. In his experience, stridor
+has been more frequent with morphia than without, particularly if
+chloroform be the anæsthetic chosen. Beyond that he cannot at present
+go.</p>
+
+<p>(5) <span class="smcap">Pressure upon the Air Passages of Neoplastic or Inflammatory
+Swellings in the Neck.</span>—In such cases any obstruction which may
+exist before induction will probably become intensified during the
+process, and a complete arrest of respiration is not uncommon. Large
+goîtres are the most common type of neoplasm to give trouble, and all
+acute inflammatory conditions in the neck which extend towards the
+trachea are notorious for their tendency to give cause for anxiety
+during anæsthesia.</p>
+
+
+<h3><b>The Physiology of Asphyxia.</b></h3>
+
+<p>An animal, subjected to asphyxia, either mechanically or otherwise,
+shows the following signs:—</p>
+
+<div class="blockquot">
+
+<p>(<i>a</i>) <i>Increase of the force and frequency of the
+respiratory movements of chest and abdomen.</i> Even though
+there be a complete mechanical obstruction, increased efforts
+to breathe will still be made for some moments, although air no
+longer passes in and out of the chest.</p>
+
+<p>(<i>b</i>) There is a considerable rise of blood pressure owing
+to a high degree of vaso-construction.</p>
+
+<p>(<i>c</i>) The pupils dilate.</p>
+
+<p>(<i>d</i>) Generalised convulsions.</p>
+
+<p>(<i>e</i>) The animal succumbs finally from cardiac failure.
+No heart muscle can continue to function properly if supplied
+by the coronary arteries with venous blood. Moreover, the
+heart<span class="pagenum" id="Page_18">[18]</span> pump has to act against the greatly increased peripheral
+resistance induced by vaso-constriction. It must therefore be a
+matter of time only when the strongest and healthiest heart will
+cease to contract under the abnormal conditions of asphyxia.</p>
+</div>
+
+<p>There are in asphyxia, two alterations in the blood-gasses, <i>i.e.</i>
+lack of oxygen and increase of CO<sub>2</sub>. The action of these two
+conditions have been differentiated by experimental work (Starling,
+Kayala, Jerusalem), and one can say definitely that the excess of
+CO<sub>2</sub> is the cause of the increased activity of the respiratory
+efforts, and that the remaining phenomena are due to oxygen starvation.
+This point is of some importance in considering anæsthetic methods
+in which re-breathing (breathing in and out of a bag) is practised.
+The use of such methods has often been thoughtlessly condemned as
+“poisoning the patient with his own CO<sub>2</sub>.” Within the limits usually
+practised, a re-breathing method does not involve any such risk,
+provided oxygen starvation does not occur. This point is referred to
+again in Chapter iv.</p>
+
+
+<h3><b>Clinical Signs of Mechanical Asphyxia in the Anæsthetised Subject.</b></h3>
+
+<p>The classical signs of asphyxia above described are hardly to be
+expected in the operating theatre, but essentially the condition
+of the patient who develops respiratory obstruction while under an
+anæsthetic is similar to that produced experimentally in animals in the
+laboratory. The changes most easily observed are as follows:—</p>
+
+<div class="blockquot">
+
+<p>(1) <i>Alteration of the colour.</i>—Cyanosis shows itself
+earliest in the lips, and the lobules of the ears,—later the
+whole face becomes dusky.</p>
+
+<p>(2) <i>Dilatation of the pupil</i>, which ceases to respond to
+the stimulus of light.</p>
+
+<p><span class="pagenum" id="Page_19">[19]</span></p>
+
+<p>(3) <i>The respiratory movements increase in depth and
+frequency.</i>—The chest and abdominal walls heave forcibly; but</p>
+
+<p>(4) <i>The volume of air passing in and out of the glottis is
+diminished.</i>—In complete obstruction, of course, none passes
+at all. In passing we may draw the moral that persistence of
+chest movements is no proof of the passage of air in and out
+of the chest: that can only be proved by hearing the movement
+of air through glottis and mouth or nose, or feeling it on the
+delicate skin of the back of the observer’s hand.</p>
+
+<p>(5) <i>True convulsions are not seen</i>, unless we may consider
+the jactitation of deep N<sub>2</sub>O anæsthesia as such (see Chapter
+<span class="allsmcap">VII.</span>). Nevertheless, there are obvious and most
+valuable signs of asphyxia to be found in the muscular system
+often quite early. These consist in the incidence of <i>muscular
+rigidity</i>, which is frequently observed first in the
+muscles of the abdominal wall. A surgeon performing laparatomy
+will notice at once the occurrence of this phenomenon, than
+which hardly anything can complicate and delay his task more
+effectively. The anæsthetist who knows his work will, upon
+hearing from the surgeon a complaint as to the rigidity of
+the abdominal wall, devote his attention first to securing a
+perfectly free air-way before deciding that a deeper anæsthesia
+is required.</p>
+</div>
+
+  <div class="figcenter" id="i_p020" style="max-width: 527px">
+     <img
+    class="p1"   
+    src="images/i_p020.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 5.</span>—Vicious circle of asphyxia.</p>
+     </div>
+
+
+<h3><b>Prevention and Treatment of Asphyxia.</b></h3>
+
+<p>Once asphyxia, especially mechanical asphyxia, has begun, it almost
+invariably tends to get worse. The engorgement affects among other
+venules, those which run under the mucous membrane of the respiratory
+tract, still further obstructing the passage of air. The muscular
+rigidity, moreover, soon manifests itself in the<span class="pagenum" id="Page_20">[20]</span> adductors of the
+vocal cords and the muscles which close the jaws: the patient has
+thus entered into a “vicious circle,” Fig. 5. It is evident that the
+prevention of the earliest signs of asphyxia is to the anæsthetist a
+matter of vital interest. The cardinal points to watch are as follows:—</p>
+
+<div class="blockquot">
+
+<p>(1) Keep the neck of the patient as far as possible in a natural
+position, <i>i.e.</i> do not either flex or extend the head
+unduly upon the body unless the nature of the operation demands
+such an unusual position.</p>
+
+<p>(2) Maintain a free passage for air either through the nose or
+the mouth.</p>
+
+<p><span class="pagenum" id="Page_21">[21]</span></p>
+
+<p>(3) Keep the lower jaw in good position throughout the
+administration.</p>
+
+<p>(4) Avoid turning the face from the lateral to the dorsal (face
+up) position unless essential. If it has to be done, be careful
+first to mop out any “pool” from the dependent cheek.</p>
+
+<p>(5) Deal as effectively as possible with the earliest appearance
+of laryngeal stridor.</p>
+</div>
+
+<p>Let us see how in a normal case, these rules can be applied. With
+the patient lying (or, in exceptional circumstances, sitting) in a
+comfortable position, the shoulders and head raised above the rest of
+the body and the face looking upwards (or straight forwards, in the
+case of the sitting patient), the anæsthetic is begun slowly, and the
+patient encouraged to take his time and to breathe naturally. At this
+stage the jaw needs no support, the muscles being neither relaxed by
+deep anæsthesia, nor spastic from asphyxia. With the advent of muscular
+relaxation, the head is turned to one side, that which is opposite to
+the side on which the surgeon will be working, being usually chosen.
+We must now determine whether the patient can breathe best through the
+mouth or the nose, and make sure that the channel chosen is as free as
+possible. In the majority of cases it will be found that respiration is
+oral, and that all that is necessary is to support the lower jaw by a
+finger hooked into the depression just below the symphysis mentes. The
+hands of the anæsthetist, therefore, take up a position from which in
+nine cases out of ten they will never require to be moved.</p>
+
+<p><i>The hand of the side toward which the patient’s face is turned</i>
+supports the jaw and keeps the face-piece or mask adapted to the face.
+The middle finger is pressed into the space below the symphysis mentis,
+and <i>exercises traction forwards and a little upwards</i>, thus
+preventing the jaw from slipping backwards; the<span class="pagenum" id="Page_22">[22]</span> index finger lies
+along the lower part of the mask, maintaining adaptation between it
+and the chin; the thumb bears on the mask higher up, keeping its upper
+part pressed against the bridge of the patient’s nose, and also serving
+as a <i>point d’appui</i>, or fulcrum, from which the jaw traction
+by the middle finger can conveniently be exercised. This grip once
+learnt is not fatiguing to the hand, and is in the author’s opinion one
+of the essential points for the beginner to master (<i>see</i> Fig.
+<a href="#i_p084b">28<span class="allsmcap">C</span></a>, page 85).</p>
+
+<p><i>The opposite hand</i> holds the drop bottle, if the method in use is
+an open one, the wrist resting upon the uppermost side of the patient’s
+head.</p>
+
+  <div class="figcenter" id="i_p022" style="max-width: 595px">
+     <img
+    class="p1"   
+    src="images/i_p022.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 6.</span>—Hewitt’s dental props.</p>
+     </div>
+
+<p>Fig. 28<span class="allsmcap">C</span> shows this grip in operation, while Fig. 28<span class="allsmcap">D</span>
+shows the alternative frequently adopted. This alternative has various
+disadvantages. It covers up a larger part of the patient’s face than
+the method recommended, and it tends to tilt the mask sideways. The
+little finger is supposed to be hooking forward the jaw by pressing
+behind its angle, but such a method is very fatiguing if in use for
+more than a few moments.</p>
+
+<p>In a proportion of cases, it is found that a free air-way cannot be
+maintained by these simple measures. Upper or lower teeth<span class="pagenum" id="Page_23">[23]</span> (or both)
+may be missing and traction upon the lower jaw only closes the mouth
+the more firmly. In most of these cases, the difficulty can be met by
+the use of the <i>dental prop</i>. These are made in various sizes and
+shapes, of which the best known are Hewitt’s and Bellamy Gardner’s
+(<i>see</i> Figs. <a href="#i_p022">6</a> and <a href="#i_p023a">7</a>). The latter are made of aluminium and are
+of small size only. They are the most convenient for cases with teeth
+both in the upper and lower jaw, but who suffer from a receding lower
+jaw not easily kept forward unless the prop is used as a rocker, as it
+were, upon which it can be slid forward. Hewitt’s props are of plated
+metal, with lead on the cups, to avoid injury to the teeth. They are
+made in five sizes, of which the middle and larger are very convenient
+for cases in which one or both rows of teeth are missing.</p>
+
+  <div class="figcenter" id="i_p023a" style="max-width: 618px">
+     <img
+    class="p1"   
+    src="images/i_p023a.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 7.</span>—Bellamy Gardner’s Dental Props.</p>
+     </div>
+
+  <div class="figcenter" id="i_p023b" style="max-width: 417px">
+     <img
+    class="p1"   
+    src="images/i_p023b.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 8.</span>—Phillips’ modification of Hewitt’s
+artificial airway.</p>
+     </div>
+
+<p>For cases entirely without teeth, and in which a large flabby tongue
+is prone to fall back over the epiglottis, the mouth tube (Fig. 8) is
+very convenient. The rubber shank lies along the top of the tongue, the
+metal end lies between the gums. As originally introduced by Hewitt,
+the air-way was circular in cross section, but the flattened model
+figured is a distinct improvement. It was introduced by Dr Phillips.</p>
+
+  <div class="figcenter" id="i_p023c" style="max-width: 525px">
+     <img
+    class="p1"   
+    src="images/i_p023c.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 9.</span>—Silk’s nasal tubes.</p>
+     </div>
+
+<p>Occasionally one decides to facilitate nasal rather than oral<span class="pagenum" id="Page_24">[24]</span>
+breathing, and if the natural passages are inadequate, recourse may be
+had to the passage of a short piece of drainage tube of the calibre of
+a number 10 catheter, and about 3 inches in length. With such a tube
+in one or both sides of the nose, reaching from anterior to posterior
+nares, nasal respiration is usually possible even in much obstructed
+noses (Silk). (Fig. 9.)</p>
+
+  <div class="figcenter" id="i_p024a" style="max-width: 213px">
+     <img
+    class="p1"   
+    src="images/i_p024a.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 10</span><span class="allsmcap">A.</span>—Bellamy Gardner’s
+tongue-clip.</p>
+     </div>
+
+  <div class="figcenter" id="i_p024b" style="max-width: 204px">
+     <img
+    class="p1"   
+    src="images/i_p024b.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 10</span><span class="allsmcap">B.</span> Ring tongue forceps.</p>
+     </div>
+
+  <div class="figcenter" id="i_p024c" style="max-width: 150px">
+     <img
+    class="p1"   
+    src="images/i_p024c.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 10</span><span class="allsmcap">C.</span> Glossotilt.</p>
+     </div>
+
+  <div class="figcenter" id="i_p025a" style="max-width: 600px">
+     <img
+    class="p1"   
+    src="images/i_p025a.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 11</span><span class="allsmcap">A.</span>—Boxwood wedge for opening
+jaws.</p>
+     </div>
+
+  <div class="figcenter" id="i_p025b" style="max-width: 228px">
+     <img
+    class="p1"   
+    src="images/i_p025b.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 11</span><span class="allsmcap">B.</span>—Wedge for opening jaws.</p>
+     </div>
+
+  <div class="figcenter" id="i_p025c" style="max-width: 220px">
+     <img
+    class="p1"   
+    src="images/i_p025c.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 11</span><span class="allsmcap">C.</span>—Mouth gag.</p>
+     </div>
+
+<p>If proper and timely use be made of one or other of these simple
+devices, the use of the <i>tongue forceps</i> is rarely necessary.</p>
+
+<p><span class="pagenum" id="Page_25">[25]</span></p>
+
+<p>Occasionally, however, it may be required, and a suitable appliance
+should always be at hand for an emergency. Fig. 10 shows two types. The
+little clip of Mr Bellamy Gardner is preferable to the ring type, the
+passage of the spike through the tongue substance producing less after
+pain, than the bruising following the use of the other instrument. The
+third drawing in Fig. 10 is of an<span class="pagenum" id="Page_26">[26]</span> instrument not much known outside
+Edinburgh; it is called a glossotilt, and is intended to lever forward
+the base of the tongue, as an alternative to nipping the tip of the
+organ with forceps, and has, in the opinion of some, various advantages.</p>
+
+<p>Before using either mouth prop or tongue forceps, it is occasionally
+necessary to use some mechanical means to lever open a tightly clenched
+jaw. The earlier one interferes in a case of mechanical asphyxia, the
+less necessity will exist for the use of such means. Fig. 11 shows two
+well-known mouth gags, and also a box-wood wedge, the use of which is
+less liable to injure teeth than a metal instrument. If a gag is used,
+the blades when closed should lie the one behind the other, not side
+by side. This ensures a minimal thickness to be inserted between the
+tightly clenched teeth.</p>
+
+
+<h3><b>Treatment of Laryngeal Stridor.</b></h3>
+
+<p>This is of necessity difficult since the causation of the condition
+is in many cases obscure. <i>The error</i> common to most beginners,
+and to many who would resent such a title being applied to them, is
+to regard the appearance of stridor as an indication to <i>deepen
+the anæsthesia</i>. Whether the cause lie in local irritation of
+the laryngeal mucous membrane or in some stimulus from the area of
+operation, the condition is presumably always essentially a reflex
+spasm of the adductors of the vocal cords, but it is a <i>reflex which
+may persist even in an anæsthesia so deep that the vital medullary
+centres are in peril</i>.</p>
+
+<p>The preventive treatment consists chiefly in following the other rules
+set forth above for the prevention of asphyxia with such faithful care,
+that the patient never enters into the vicious circle of asphyxia of
+which stridor is so prominent a feature. Patience in the induction
+stage—the avoidance of <i>forcing</i> the anæsthetic upon the
+patient—is a safeguard not to be forgotten.</p>
+
+<p>Once the condition has arisen, it saves time to <i>withdraw the<span class="pagenum" id="Page_27">[27]</span>
+anæsthetic</i> altogether, and to allow the patient to breathe nothing
+but fresh air. Brisk friction of the lips with a rough towel often
+does good, presumably by setting up a “cross reflex.” In severe cases,
+a most valuable measure is the inhalation of pure oxygen, a cylinder
+of which should always be at hand in the operating theatre. Even an
+obstructed air-way will convey enough undiluted oxygen to reduce the
+venosity of the blood, and so cut across the “vicious circle.”</p>
+
+<p>So much for the treatment of the early stages of asphyxia, the more
+advanced stages constitute one of the “accidents of anæsthesia,” and
+are dealt with in Chapter <span class="smcap">xvi</span>.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_28">[28]</span></p>
+
+<h2>CHAPTER IV.<br>
+<span class="subhed"><b>METHODS OF ANÆSTHETISING.</b></span></h2></div>
+
+<p>Certain terms such as “open method,” “closed method,” etc., are used in
+describing different systems of anæsthetising, and it will save time
+later if these are now defined.</p>
+
+<p>The <span class="smcap">Open Method</span> is one in which the drug is dropped or
+poured upon a fabric stretched on a mask which does not lie in close
+apposition to the face. If the student will experiment with such a
+mask as Schimmelbusch’s, he will find that by no effort can he make
+its whole circumference touch his face at the same time. Anæsthetics
+vapourised from such masks must of necessity be inhaled freely diluted
+with fresh air. These masks are only suitable for use with chloroform.</p>
+
+<p>The <span class="smcap">Perhalation Method</span>.—This term is not used often, but
+it is the most strictly correct name to give to the process commonly
+called “open ether.” If the student will examine Bellamy Gardner’s open
+ether mask (Fig. 27) he will find that it is deliberately shaped to lie
+over its entire circumference in close apposition to the face of the
+average patient. In actual use it is well however to make sure of this
+apposition by the use of a ring of gauze as shown in Fig. 28<span class="allsmcap">A</span>.
+Upon the mask is stretched gauze of a thickness just as great as will
+permit free respiration to take place through its layers. The whole
+bulk of the respired air must pass <i>through the fabric</i>, none
+escaping between the face and mask.</p>
+
+<p>The term “<span class="smcap">Semi-Open</span>” is applied to various methods now rarely
+seen. One of the best known of these was the anæsthetic cone, still
+used by a few for C.E. mixture (<i>see</i> Fig. <a href="#i_p131">45</a>).</p>
+
+<p><span class="pagenum" id="Page_29">[29]</span></p>
+
+<p>The term “<span class="smcap">Closed Method</span>” is applied to one in which the
+patient breathes in and out of a closed bag. The Clover and Ormsby
+inhalers are “closed” instruments. With this method the patient rapidly
+uses up the oxygen of the contained air, and accumulates considerable
+CO<sub>2</sub>; life could not be sustained for any long period of time under
+such a system. Oxygen must be supplied from time to time by permitting
+say one breath in five to be taken from the fresh air instead of from
+that in the bag. Alternatively, oxygen from a cylinder may be supplied
+by an accessory pipe into the inhaler.</p>
+
+<hr class="tb">
+
+<p>This method is also referred to as the <span class="smcap">Re-Breathing Method</span>.</p>
+
+<hr class="tb">
+
+<p>The <span class="smcap">Valved Method</span> is used only with “gas” or “gas-oxygen.”
+The facepiece fitting accurately, the patient draws all the volume of
+his inspiration from the inhaler: his expirations he propels through
+a valve, into the general atmosphere of the room. If nitrous oxide
+unmixed with oxygen is being given, the patient suffers from oxygen
+starvation even more rapidly and completely than in the re-breathing
+method. During the induction period of gas anæsthesia, such oxygen
+starvation is practised deliberately, and if not pushed too far is
+harmless. It cannot, however, be continued for more than a brief space
+of time. The admixture of oxygen to the vapour being breathed entirely
+abolishes this unfavourable feature of the valved method.</p>
+
+<p>There is, however, another consequence of the use of “valves” which
+is unaffected by the addition of oxygen. Reference has already been
+made to <i>Yandell Henderson’s acapnic theory</i>, and if under
+any form of anæsthesia the patient can be reduced to a condition
+<i>of CO<sub>2</sub> starvation</i>, it will be when the valved system of
+administration is in operation for a prolonged period. As a matter of
+experience, patients breathing “on the valves” do often exhibit shallow
+respirations and slight pallor which is rapidly and very strikingly
+remedied by turning to the rebreathing method. One<span class="pagenum" id="Page_30">[30]</span> can hardly doubt
+that the improvement is due to a gradual re-accumulation of carbon
+di-oxide in the blood and tissues.</p>
+
+<p>Two other terms referring not to the type of inhaler but to the method
+of supplying the drug, are in use.</p>
+
+<p>By the <span class="smcap">“Drop” Method</span>, we mean one in which the anæsthetic is
+supplied in a steady series of drops. The flow may be quick or slow,
+but it always arrives on the mask in isolated drops of uniform size.
+Such a method demands more constant attention than the next to be
+described, but it is capable of yielding that even uniformity of vapour
+strength so desirable in open methods.</p>
+
+<p><span class="smcap">The Douche Method</span> is unfortunately far more commonly used by
+those whose attention has never been drawn to the significance of the
+difference between the two. Supplies of the drug rendered, say, every
+twenty seconds cannot possibly give an even vapour strength.</p>
+
+<p>“<span class="smcap">Single Dose</span>” methods are of use chiefly in dental surgery.
+The patient is charged up with the anæsthetic, and the operator has to
+begin his work as soon as the mask is withdrawn from the face, ceasing
+as soon as the patient shows any signs of recovering consciousness of
+pain.</p>
+
+<p>Single dose anæsthetics are in a class by themselves. In order to
+achieve success with them, special experience on the part of the
+administrator and mutual confidence between operator and anæsthetist
+are essential.</p>
+
+<p>The period of anæsthesia available to the operator which any particular
+“single dose” anæsthetic may be expected to yield is obviously a matter
+of the first importance, and the table given in Chapter <span class="smcap">xix</span>.
+will be found helpful in this connection.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_31">[31]</span></p>
+
+<h2>CHAPTER V.<br>
+<span class="subhed"><b>THE CLINICAL OBSERVATION OF THE PATIENT.</b></span></h2></div>
+
+
+<h3><b>Stages of Anæsthesia.</b></h3>
+
+<p>Anæsthesia has been divided into four clinical stages corresponding
+to the degrees to which the nervous system has been affected. The
+boundaries between these stages are often ill-defined, but the
+terminology has some value as facilitating description.</p>
+
+<p><span class="smcap">The First Stage</span> lasts from the commencement of inhalation up
+to the time when volitional self-control is lost by the patient.</p>
+
+<p><span class="smcap">The Second Stage</span> in the older text-books was said to be
+characterised by struggling, shouting, and breath-holding. With a
+patient not addicted to alcohol and with the anæsthetic skilfully
+administered, this description is unduly lurid.</p>
+
+<p><span class="smcap">The Third Stage</span> is that of full surgical anæsthesia.</p>
+
+<p><span class="smcap">The Fourth Stage</span> is that of over-dosage.</p>
+
+
+<h3><b>The Ocular Reflexes in Anæsthesia.</b></h3>
+
+<p>These give such valuable assistance to the anæsthetist that it will be
+well to define and describe them as a preliminary. They are three in
+number.</p>
+
+<p><span class="smcap">The Conjunctival Reflex</span> is best elicited by drawing the
+upper lid upwards from the eyeball and retaining it in that position
+with one finger, while with another finger the ocular conjunctiva is
+lightly touched in the area of the inner canthus. If the anæsthesia is
+very light, both lids attempt to approximate<span class="pagenum" id="Page_32">[32]</span> and close the palebral
+fissure. The upper lid may slip down from under the retaining finger
+and come into its proper place, while the lower lid is elevated. At
+a deeper level of anæsthesia there is not complete action of the
+orbicularis but merely of a certain part of it, so that all that is
+observed is a <i>twitch inwards of the lower lid</i>. Even this form of
+the reflex disappears before the corneal reflex.</p>
+
+<p><span class="smcap">The Corneal Reflex</span> is elicited by pushing up the upper lid by
+one finger and with the pulp of the <i>same</i> finger lightly brushing
+the centre of the cornea as soon as it is exposed, when we feel or see
+the upper lid come back into position with a sharp definite twitch.
+The examining finger must be slipped smartly out of the way as soon as
+the cornea has been touched. Even in deep anæsthesia, a trace of this
+reflex can usually be elicited if the little manipulation be properly
+performed.</p>
+
+<p>The conjunctival and corneal reflexes are frequently confused in the
+mind of the student. The most common mistake made is to pin the upper
+lid firmly somewhere in the region of the bony roof of the orbit,
+to dab the eye far too vigorously, and to believe that no reflex is
+present because no movement of the upper lid takes place. In the first
+place, the upper lid cannot move if it is rigidly held against a bony
+plate: in the second place, it is wholly unnecessary to inflict upon
+the cornea more than the lightest of touches. Both these reflexes
+are to be used with great discretion, undue frequency and excessive
+vigour of touch being alike capable of setting up serious inflammatory
+reaction.</p>
+
+<p><span class="smcap">The Pupillary Light Reflex</span> is elicited by shutting off light
+from <i>both</i> pupils for ten to twenty seconds and then smartly
+withdrawing the protecting fingers and allowing as strong a light as
+possible to fall on to the eye. The response of the ciliary muscle
+should <i>always</i> be present; its absence is a certain indication of
+something wrong: some sluggishness may be permissible under<span class="pagenum" id="Page_33">[33]</span> ether, but
+even that is suggestive of trouble if chloroform is the anæsthetic.</p>
+
+<p>The use of a preliminary hypodermic of morphia tends to make the pupil
+somewhat smaller than normal, and to elicit the light reflex it may be
+necessary to cut off illumination for a somewhat longer period than
+if no morphia had been given. Nevertheless with a little care, the
+light reflex should always be capable of demonstration even in the
+morphinised subject.</p>
+
+
+<h3><b>The Observation of a Normal Case.</b></h3>
+
+<p>In the case of nitrous oxide and of ethyl chloride, the patient passes
+through the various stages very rapidly, and the picture of anæsthesia
+as induced by either of these two is therefore best described
+separately. The following may be taken, therefore, as an account of
+what is to be observed in the patient inhaling ether or chloroform,
+unless a specific reference is made to one of the other anæsthetics.</p>
+
+<p><span class="smcap">First Stage.</span>—The first sign that some effect is being
+produced in the patient is usually the appearance of the movements of
+<i>swallowing</i>; the hyoid and thyroid can be felt or seen to be
+moving in conjunction with the muscles of deglutition. During this
+stage, the patient being still to some extent under volitional control,
+there should be no other movement noticed. The eyes are usually closed
+and the colour normal; the respiration may be hurried by excitement,
+but judicious handling of the patient will do much to minimise this.</p>
+
+<p><span class="smcap">The Second Stage</span> is really entered when volitional control
+is lost. It may be characterised by struggling and shouting by the
+patient, even if the anæsthetic is properly administered; but with a
+healthy patient and a good anæsthetist, all that usually occurs in
+the way of movement by the patient is some rigidity of the limbs and
+a slight attempt, perhaps, to lift the head from the pillow or a limb
+from the couch. The breathing tends during the first part<span class="pagenum" id="Page_34">[34]</span> of this
+stage to be light and is rarely entirely regular: slight pauses occur,
+usually after an inspiration, less commonly after expiration. Serious
+“holding of the breath” (after an inspiration) rarely occurs save in
+the type of patient who is also struggling; if it does occur to a
+degree which causes any blueness of the patient’s face (cyanosis), it
+usually calls for the removal of the anæsthetic for a moment until
+normal breathing has been resumed.</p>
+
+<p>The colour of the face rarely departs much from normal during the
+second stage, unless cyanosis from breath-holding intervenes.</p>
+
+<p>The eyes are usually opened, as the second stage progresses, and the
+eyeballs tend to rotate slowly in every plane. The pupils are usually
+large, but react sharply to light. Both conjunctival and corneal
+reflexes are brisk.</p>
+
+<p><span class="smcap">The Onset of the Third Stage</span> is marked by the appearance of
+muscular relaxation. Any limb which the patient may have been holding
+rigidly up sinks down on to the couch, and it will be found that if an
+attempt be now made by the anæsthetist (as it should be) to turn the
+head of the patient to one side or another, the muscles of the neck no
+longer resist.</p>
+
+<p><i>The respiration</i> also alters in type, losing its tendency to
+lightness and irregularity, and becomes full, deep, and regular. In
+open ether anæsthesia particularly, expiration commonly assumes a
+“blowing” type very characteristic, and which to the trained ear is of
+itself an indication that full surgical anæsthesia is present or at any
+rate not far distant.</p>
+
+<p><i>The colour</i> varies somewhat with the anæsthetic in use. With
+ether it is usually somewhat higher than normal, and a trace of
+blueness may be present if the method is the “closed” one. Anything
+more than a trace, however, must be regarded as abnormal, whatever the
+method or anæsthetic may be. With chloroform the colour is perhaps a
+little paler than that normal to the individual.</p>
+
+<p><span class="pagenum" id="Page_35">[35]</span></p>
+
+<p><i>The eyelids</i> are usually half open, and the eyeballs at rest
+looking forward and slightly downwards. An extreme rotation downward
+may usually be taken as a sign of very deep anæsthesia. <i>The
+pupil</i> is, as already said, always active to light, but its actual
+size varies with the anæsthetic used. With ether, particularly “closed”
+ether, it may be large (4–5 millimetres): with open ether, preceded by
+morphia, about 3–4 millimetres: a good chloroform anæsthesia usually
+exhibits a pupil of only 2–3 millimetres, and if morphia has also been
+given, it may be pin-point in size. Too much emphasis must not be
+placed, however, upon the mere size of the pupil; that may vary within
+wide limits without necessarily indicating serious abnormality. The
+essential point is that the light reflex shall be brisk. A pupil of 5
+millimetres reacting sharply to light may be of no special moment: one
+of that size immobile to light would cause real anxiety.</p>
+
+<p><i>The conjunctival reflex</i> usually disappears fairly early in
+the third stage: if briskly present, the anæsthesia is certainly a
+light one, and probably insufficient for an abdominal section. <i>The
+corneal reflex</i> if properly taken in the way already described can
+usually be elicited throughout the third stage. In an anæsthesia deep
+enough for abdominal section it is, of course, not brisk, but we may
+say generally that its entire absence is <i>presumptive</i> evidence
+of a very deep anæsthesia—probably undesirably deep. It must not be
+forgotten that some local causes such as drying of the surface of the
+cornea may cause it to disappear, and in case of doubt it is sometimes
+worth while to wash out the eye with a little saline solution. If after
+doing so the anæsthetist still finds the reflex not present he should
+be on his guard. Provided, however, that the light reflex is still
+present and colour and respiration satisfactory, he need not consider
+that the patient is in any immediate danger.</p>
+
+<p>Broadly speaking, then, the third stage, the stage which is called for
+by the requirements of major surgery, is characterised by<span class="pagenum" id="Page_36">[36]</span> (1) full
+regular respirations; (2) colour not much removed from normal; (3)
+moderate sized pupil, larger in the case of ether than chloroform; (4)
+conjunctival reflex faint or absent; (5) corneal reflex just present,
+or, in a deep third stage, just absent; (6) light reflex present:
+these may be regarded <i>as the signs of fully developed surgical
+anæsthesia</i>.</p>
+
+<p>The absolute beginner may be so completely out of his reckoning as
+to mistake the quietude of the later part of the first stage for the
+appearance of the third stage. For the prevention of so gross an
+error as that, the reader need only be referred to a patient study
+of the foregoing. But even a man with considerable experience may
+frequently be in doubt exactly as to <i>how far through the third
+stage his patient has passed</i>. He may have attained a level which
+will permit an incision to be made into the skin without movement on
+the part of the patient, but not one which would relax the abdominal
+muscles sufficiently for the peritoneum to be opened without eliciting
+considerable resistance from the abdominal muscles. In such moments
+of doubt, the author is accustomed to request the surgeon to make his
+skin incision, and <i>observe the effect which this trauma has upon the
+depth, frequency, and regularity of respiration</i>. This furnishes a
+most valuable guide to the depth of anæsthesia. In a third stage of
+very light degree, the respiratory rhythm will be interrupted and the
+breath held for a second in inspiration. Apart from any other sign,
+that may be taken as an index that the anæsthesia is very light—too
+light to permit of opening the peritoneal cavity. In a very deep
+anæsthesia the respiration is little affected by the skin incision,
+while at a moderate and more desirable level the respiration is
+quickened and deepened, but unaffected in the regularity of its rhythm.</p>
+
+<p><span class="smcap">The Fourth Stage is Stage of Over-Dose.</span>—This stage is, of
+course, never entered voluntarily. Its earliest signs are loss of all
+tone in the muscles of expression, complete loss of corneal<span class="pagenum" id="Page_37">[37]</span> reflex,
+a widely dilated pupil <i>insensitive to light</i>, and a type of
+respiration which though definitely weakened may show occasional deep
+gasps. Circulatory failure and cessation of respiration from failure of
+the medullary centre are the closing phenomena of overdose.</p>
+
+
+<h3><b>The Circulation in Anæsthesia.</b></h3>
+
+<p>It will be perhaps noticed that in the foregoing, no reference has
+been made to the examination of the pulse. This is not an oversight on
+the part of the author. It is perfectly true that under any anæsthetic
+not complicated by an asphysical element, the blood pressure falls as
+the drug takes effect, and that in the case of chloroform the fall is
+often quite considerable. Such a fall can be appreciated by the skilled
+finger, but only by concentrating upon that examination a degree of
+attention which necessarily detracts from the administrator’s available
+energy for the observation of other signs which are of equal value, and
+can be more rapidly and certainly appreciated and appraised.</p>
+
+<p>It is nevertheless essential to assure oneself during the whole
+progress of an anæsthesia that the circulation is in a satisfactory
+condition. Two obvious guides to this are the colour of the patient’s
+face and the force with which cut arteries spout. As regards the colour
+in circulatory failure, one would naturally expect a pallid face, and
+this indeed is the rule. It must not be forgotten, however, <i>that
+cyanosis may sometimes be cardiac in origin</i>. Cases do sometimes
+occur when a bluish tinge is seen on the lips, ears, and nostrils,
+apart from any obvious cause of oxygen starvation. In these we may
+reasonably suspect that the right heart is failing, and take measures
+accordingly.</p>
+
+<p>Another valuable index to the state of the circulation is the “skin
+reflex,” that is, the speed with which the circulation returns to an
+area of the skin which has been pinched. The student should train his
+eye by occasionally pinching the lobule of the<span class="pagenum" id="Page_38">[38]</span> patient’s ear and
+observing first the white area so produced, and later the rate at
+which, in a normal case, the healthy colour returns.</p>
+
+
+<h3><b>Abnormal Phenomena in Anæsthesia.</b></h3>
+
+<p>It is not intended to furnish here any account of matters more suitably
+treated under the “Accidents of Anæsthesia,” which are fully described
+in Chapter xvi., but merely to draw the attention of the student to
+certain departures from the normal course of anæsthesia which are
+encountered with varying frequency, to ascribe them as far as possible
+to their true causation, and indicate methods of prevention.</p>
+
+<p>The abnormalities fall into two classes, those connected with the
+nervous and muscular systems, and those in which respiratory changes
+are evident.</p>
+
+
+<h4 class="smcap">Motor and Nervous System.</h4>
+
+<p><i>Clonus or tremor</i> sometimes appears in one or more limbs, even
+the trunk being affected in severe cases. Ether is practically the
+only anæsthetic under which the tremor ever appears, and the condition
+is often spoken of as “ether tremor.” It rarely appears in the female
+subject, being almost limited to powerfully built young men. Coming
+on towards the end of the second stage, it frequently persists in the
+deepest of third stages, and in bad cases there is usually no option
+but to change over to chloroform—always supposing that the tremor will
+interfere with the work of the surgeon. If it will not, the condition
+calls for no active treatment, since it is in itself not dangerous.</p>
+
+<p><i>Movements recalling to the observer the condition of athetosis
+seen in the limbs of hemiplegics</i> are occasionally seen in the
+anæsthetised patient. The fingers of a hand may be slowly moved, or one
+or other shoulder may be shrugged. The exact cause of these movements
+is obscure. They occur in all types, both sexes, and at all ages; they
+are not necessarily asphyxia though a trace of asphyxia seems sometimes
+to conduce to them. They persist for<span class="pagenum" id="Page_39">[39]</span> some time after the third stage
+has been entered, and ultimately disappear without any obvious cause
+other than the passage of time. It is rare for them to continue more
+than five or ten minutes after full anæsthesia has been induced. Their
+practical importance lies purely in this, that the inexperienced
+anæsthetist observing some muscular movements still persisting, may
+take them as an infallible sign that anæsthesia is not complete, and
+may deliberately take his patient to a deeper level. If in doubt,
+the anæsthetist must, of course, consult all the other recognised
+guides, such as the eye reflexes, but once he has seen these movements
+in a case, and had demonstrated to him <i>their slow, rhythmical
+character</i>, he is not likely to be misled on a future occasion.</p>
+
+<p><i>Muscular rigidity</i> has been mentioned already in Chapter iii.
+When it persists in a patient in whom other signs suggest that a full
+anæsthesia has been produced, the anæsthetist will usually find that
+attention to the air-way, and perhaps a whiff of oxygen, will remedy
+the trouble.</p>
+
+
+<h3><b>Respiratory Abnormalities.</b></h3>
+<p><i>Shallow breathing</i> or even slight temporary arrests of
+respiration arise frequently. During the induction stage they may be
+due to:—</p>
+
+<div class="blockquot">
+
+<p>1. Apnœa or acapnia following voluntary excessive breathing.</p>
+
+<p>2. Using morphia before chloroform.</p>
+</div>
+
+<p>At a later stage, it may be due to:—</p>
+
+<div class="blockquot">
+
+<p>1. Acapnia following excessive breathing excited reflexly from
+the seat of operation.</p>
+
+<p>2. Direct reflex inhibition of the respiratory centre.
+An example of this is seen sometimes when the bladder is
+over-distended by lotion.</p>
+
+<p>3. Impending vomiting.</p>
+</div>
+
+<p><span class="pagenum" id="Page_40">[40]</span></p>
+
+<p><i>Moist sounds</i> not uncommonly appear. The student’s general
+knowledge of medicine will enable him to decide whether the fluid is
+likely to be in the pharynx, larynx, trachea, or bronchi. If in one
+of the first two named, it will suffice to swab out the throat and
+encourage the patient to cough. If, however, moisture is evidently
+present in the trachea or bronchi, the condition is one calling for
+considerable care and judgment. It arises more commonly with ether than
+with chloroform. Much will depend upon how much longer the surgeon
+requires to finish his operation. If only a few minutes more are
+required, nothing is necessary but to cut down the amount of ether
+being given to the minimum possible. If, however, the surgeon has
+still a good deal to do, the safest thing is to withdraw the ether and
+substitute chloroform or a mixture. Be it clearly understood, however,
+that such a change over is not devoid of risk. If it is to be made, it
+must be done early, before the patient is cyanosed and almost drowned
+in his own secretion. In a neglected case where cyanosis has already
+appeared, there will be no option but to interrupt the operation,
+empty the chest by encouraging coughing, and to aid the process
+by compressing the patient’s chest during expiration. Thereafter
+chloroform may be given, but with the greatest care.</p>
+
+<p><i>Gasping and sighing</i> are not common phenomena but when they
+occur, call for close notice from the anæsthetist. Excluding, of
+course, such occurrences in the first stage, before volitional control
+has been lost, they may be <i>usually but not invariably ascribed
+to overdosage or to the appearance of definite surgical shock</i>.
+Whenever they are noticed, therefore, it behoves the administrator to
+overhaul the patient thoroughly, to consult the eye reflexes, the skin
+reflex, and the pulse, and not to rest until he is assured that there
+are no other signals of danger to be found.</p>
+
+<p><i>Stertor and stridor.</i> The first of these is caused by flapping
+of the soft palate. It is a noise low in pitch, resembling ordinary
+snoring. Indicating as it does that the palatal and therefore<span class="pagenum" id="Page_41">[41]</span> probably
+other muscles, are relaxed, it may if moderate in volume usually be
+taken as a favourable sign. If it becomes very loud, however, the
+probability is that the base of the tongue has fallen back; cyanosis
+will begin to appear, but will immediately be remedied by pulling
+forward the jaw or in extreme cases, using the tongue forceps.</p>
+
+<p><i>Stridor</i> is a high-pitched sound produced by approximation of the
+vocal cords. It has already been dealt with in Chapter iii.</p>
+
+
+<h3><b>False Anæsthesia.</b></h3>
+
+<p>This term has been applied to a condition often seen in children,
+and occasionally in adults. It is almost limited to chloroform: the
+author has never seen a genuine case when ether has been in use. It
+appears very quickly after inhalation has begun: the muscles are
+relaxed, the respirations quiet and regular, the conjunctival reflex
+sluggish. A very marked feature is the excessive smallness of the
+pupil. Obviously then, the condition much resembles a true third stage,
+but if the operation be begun, the mistake will very rapidly be made
+evident, for the patient will at once move and cry out. In essence, the
+condition is simply one of ordinary sleep. It can be recognised by its
+appearance after a period of inhalation too brief for the induction
+of true anæsthesia, by the very small pupils and the lightness of the
+respiration. It will be a waste of time to permit the condition to
+continue, as the lightness of the respiration delays the taking in of
+a dose of the anæsthetic sufficient to induce a proper third stage.
+The remedy is simple,—rub the lips and face smartly with a towel or
+the hand, when respiration will at once deepen and the pupil dilate.
+Thereafter, the induction should proceed normally.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_42">[42]</span></p>
+
+<h2>CHAPTER VI.<br>
+<span class="subhed"><b>PREPARATION OF THE PATIENT.</b></span></h2></div>
+
+<p>For all but short anæsthesias conducted chiefly by nitrous oxide, the
+intestinal tract of the patient must receive careful preparation. In
+doing this, one must avoid excessive starvation and purgation, both of
+which tend to increase shock.</p>
+
+<p>We will suppose that the operation is timed for 10 a.m. on Tuesday
+morning. On Monday morning the patient receives an aperient which
+may be varied a little to suit his taste and habits. If he has no
+preference, there is nothing better than an ounce of castor oil. During
+the rest of Monday, he has a light diet: fish and milk pudding in the
+middle of the day, a little soup at night. The aperient should operate
+before 9 p.m. When that is over, the patient retires to bed. During the
+day he may be allowed to move about his room a little, but should not
+undertake any exertion.</p>
+
+<p>If there be excessive nervousness, or a natural tendency to insomnia,
+sulphonal gr. 15 or veronal gr. 8 may be given early in the evening, to
+ensure a night’s rest.</p>
+
+<p>About 6 a.m. on Tuesday morning, a large soap and water enema is given,
+and when this has operated, a cup of tea or a little soup or Bovril may
+be taken. Thereafter nothing should be given by mouth.</p>
+
+<p>The early forenoon is the time of choice for any operation, but if
+an afternoon time be of necessity chosen, the patient should not be
+starved throughout the forenoon. A repetition of the early morning meal
+may be allowed about 11 a.m.</p>
+
+<p><span class="pagenum" id="Page_43">[43]</span></p>
+
+<p>In cases such as gastro-enterostomy, where the alimentary tract will be
+opened, the preparation must be a little more stringent. It is usual
+to allow no solids at all the day before. A saline enema may be given
+an hour or two before operation, when the soap and water has been
+evacuated.</p>
+
+
+<h3><b>Preliminary Hypodermic Medication.</b></h3>
+
+<p>This great improvement in anæsthesia was practised many years ago by
+a few surgeons, but it was only when open ether assumed its present
+position of pre-eminence that it was widely adopted.</p>
+
+<p>The present routine is to give morphia gr. ⅙, atropine gr. ¹⁄₁₂₀ to
+adult patients three quarters of an hour before operation. It has the
+following <i>advantages</i>:—</p>
+
+<div class="blockquot">
+
+<p>(1) The nervous fears of the patient give place to a feeling of
+bien-être.</p>
+
+<p>(2) The secretions of saliva and of mucous from the respiratory
+mucous membranes are limited.</p>
+
+<p>(3) A little less inhalational anæsthetic is required.</p>
+
+<p>(4) The after vomiting is lessened, and probably the liability
+to inflammatory respiratory complications also reduced.</p>
+</div>
+
+<p>The <i>disadvantages</i> can be met by proper care and dosage. They are
+as follows:—</p>
+
+<div class="blockquot">
+
+<p>(1) Morphia <i>plus</i> chloroform depresses the respiratory
+centre at an early stage of anæsthesia. Respiration becomes
+infrequent and shallow, and cyanosis appears before the patient
+is really sufficiently anæsthetised for the purposes of the
+surgeon.</p>
+
+<p>(2) The larger the dose of morphia, the more troublesome is this
+premature failure of respiration.</p>
+</div>
+
+<p><i>The moral</i> is obvious: give the small doses above recommended<span class="pagenum" id="Page_44">[44]</span>
+and induced with mixtures weak in chloroform, or better still with
+ether only (see page <a href="#Page_86">86</a>).</p>
+
+<p>Some years ago, before these facts were appreciated, there was a
+fashion for giving very large doses of preliminary narcotics. The
+combinations most favoured were as follows:—</p>
+
+
+<h4 class="smcap">Scopolamine-morphine.</h4>
+
+<p>Scopolamine is a form of hyoscyamine and is itself a powerful narcotic.
+Two or sometimes three doses of the mixed drugs were given at intervals
+of an hour, the last half an hour before operation. Scopolamine gr.
+¹⁄₂₀₀, morphia gr. ⅛ was the usual formula: some surgeons added a dose
+of atropine or strychnine with the idea of stimulating the respiratory
+centre.</p>
+
+<p>The patients went to the operating or anæsthetising room so drowsy
+that they were unaware of their surroundings, and afterwards had no
+recollection of the actual beginning of the inhalation. So humane a
+method naturally attracted a good deal of attention, but the serious
+depression of the respiratory centre which seems inevitable in the
+method has gradually caused it to disappear from the practice of
+most surgeons and anæsthetists. At the present day, it is only to
+be recommended in midwifery practice; to the drowsy semi-conscious
+condition produced, the name of <i>Twilight Sleep</i> has been given.</p>
+
+
+<h4 class="smcap">Omnopon and Omnopon-scopolamine.</h4>
+
+<p>Omnopon is composed of a mixture of several of the alkaloids derived
+from opium; the makers claim that it produces less after malaise than
+morphia alone. It may be given before anæsthesia in doses of ⅙–⅓ gr.,
+either alone or combine with a small dose of scopolamine. It gives
+quite good results if not pushed to excess.</p>
+
+
+<h4 class="smcap">Heroin Hydrochloride</h4>
+
+<p>This comparatively modern sedative is used by some surgeons in
+preference to morphia. A dose of ¹⁄₁₂ gr. is quite sufficient,<span class="pagenum" id="Page_45">[45]</span> three
+quarters of an hour before operation. Atropine should always be
+combined with it.</p>
+
+<hr class="tb">
+
+<p>To young children, morphia should not be given, but atropine may be
+given freely. A child of twelve months tolerates a dose of ¹⁄₂₀₀ gr.
+quite well: one of six years, will take ¹⁄₁₅₀ gr.</p>
+
+<p>In ages ranging from 12 years upwards, greatly reduced doses of morphia
+may be given. No child under 15 years requires more than ¹⁄₁₂ gr. of
+morphia at most.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_46">[46]</span></p>
+
+<h2>CHAPTER VII.<br>
+<span class="subhed"><b>NITROUS OXIDE.</b></span></h2></div>
+
+<h3><b>Special Physiology.</b></h3>
+
+<p>Upon the nervous system, nitrous oxide acts like other anæsthetics,
+but the stages of anæsthesia are passed through so rapidly that a
+second stage can hardly be distinguished. It is rare for struggling or
+excitement to be manifest, unless air or oxygen be admitted at the same
+time, when the effect which led Humphrey Davy more than a century ago
+to apply to nitrous oxide the name of “laughing gas” is very evident
+indeed.</p>
+
+<p>Upon the other systems of the body, nitrous oxide has little if any
+effect in itself. The essential point to remember in connection with
+nitrous oxide administered unmixed with air or oxygen is that there
+is an <i>inevitable element of asphyxia</i>. The larger part of the
+oxygen normally carried by the red blood corpuscles is eliminated
+and replaced by N<sub>2</sub>O: oxygen starvation is therefore of necessity
+present. In other words, the “vicious circle of asphyxia” (<i>see</i>
+Fig. <a href="#i_p020">5</a>) is entered, and muscular spasm is bound ultimately to appear.
+Moreover, the blood pressure rises very materially as a result of the
+lack of oxygen. That no harm results to the normal healthy patient
+from this rise is due to the fact that the gas does not in itself
+poison the heart muscle, which can therefore stand up to the extra
+strain of working against higher resistance, so long as the process
+is not carried to extremes. A heart muscle weakened by the action of
+chloroform would give out at once if exposed to such a test.</p>
+
+<p><span class="pagenum" id="Page_47">[47]</span></p>
+
+
+<h3><b>Apparatus.</b></h3>
+
+<p>Nitrous oxide is supplied by the makers as a fluid condensed in iron
+bottles or cylinders, and only becomes gaseous upon being released from
+them. In passing from the fluid to the gaseous state, heat is of course
+lost, and it will be noticed that the end of the cylinder which is in
+use becomes rapidly crusted over with frost. Ice, moreover, forms in
+the small channel at the head of a cylinder, and is apt from time to
+time to block it.</p>
+
+<p>The cylinders are of various sizes and designated after the numbers
+of gallons of gas which they will supply: 25 is the smallest size, 50
+or 100 are more usual; anything up to 500 is occasionally met with in
+hospital practice. Moreover the cylinders are of two types, called
+respectively <i>vertical</i> (for use in the upright position), and
+<i>angle</i> for use in the horizontal position (<i>see</i> Fig. <a href="#i_p048">13</a>).</p>
+
+  <div class="figcenter" id="i_p047" style="max-width: 650px">
+     <img
+    class="p1"   
+    src="images/i_p047.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 12.</span>—Frame for adapting vertical cylinders
+to foot use.</p>
+     </div>
+
+  <div class="figcenter" id="i_p048" style="max-width: 430px">
+     <img
+    class="p1"   
+    src="images/i_p048.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 13a.</span>&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;<span class="smcap">Fig. 13b.</span></p>
+     <p class="p0 center smaller">Two types of N<sub>2</sub>O cylinders.</p>
+     <p class="p0 center smaller">A. Vertical (or ordinary).&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;&emsp;B. Angle.</p>
+     </div>
+
+<p>The cylinders are fixed in frames of various types of which examples
+are seen in Figs. <a href="#i_p048">13</a> and <a href="#i_p049">14</a>.</p>
+
+<p>Upon each cylinder, of whatever size or type, will be found a label
+stating its weight when full and empty, the difference<span class="pagenum" id="Page_48">[48]</span> representing
+the weight of the contents when the bottle is full. For instance, in
+the case of the 50-gallon cylinder the weight of its full charge is 15
+ounces. Weighing the cylinder is the only certain means which we have
+to estimate how much of the charge remains. The student will readily
+appreciate therefore that once a cylinder has been used at all there
+is always a risk of the supply of gas from it running out during an
+administration. It is<span class="pagenum" id="Page_49">[49]</span> for this reason that cylinders are habitually
+used in couples, one of which is always supposed to be quite full. To
+this one it is well to attach a label marked “full,” and care must be
+taken to replace at once a cylinder known to be empty. In this way we
+always have upon the frame one cylinder partly and another entirely
+full.</p>
+
+  <div class="figcenter" id="i_p049" style="max-width: 308px">
+     <img
+    class="p1"   
+    src="images/i_p049.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 14.</span>—Complete N<sub>2</sub>O apparatus, showing
+twin cylinders, supply pipe, 2-gallon bag, 3-way tap, and face-piece.</p>
+     </div>
+
+<p><span class="pagenum" id="Page_50">[50]</span></p>
+
+<p>By whatever makers the cylinder is supplied it will be found that the
+thread upon the outlet pipe is the same, and the metal nipple figured
+in Fig. 14 will fit it. To the distal end of the nipple, a rubber tube
+is attached which leads to a rubber bag usually of 2 gallons capacity.</p>
+
+<p>The remainder of the apparatus may be of several types.</p>
+
+<p>Fig. 15 shows the ordinary <i>Barth three-way</i> tap with facepiece;
+the indicator on the tap has three possible positions designated on
+the dial as “Air,” “Valves,” and “No Valves.” If the tap is pointed
+backwards towards the bag at the position marked “air” the end of the
+bag is closed and the patient is breathing air only. With the tap in
+the middle position of “valves,” the inspiration of the patient will
+draw gas from the bag, but the expiration closes the valve which is now
+in operation at the orifice of the bag, and will open the expiratory
+valve which conducts the expired air into the general atmosphere. In
+the third position of “no valves” the patient breathes both in and out
+of the bag.</p>
+
+  <div class="figcenter" id="i_p050a" style="max-width: 592px">
+     <img
+    class="p1"   
+    src="images/i_p050a.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 15.</span>—Barth 3-way N<sub>2</sub>O tap.</p>
+     </div>
+
+  <div class="figcenter" id="i_p050b" style="max-width: 538px">
+     <img
+    class="p1"   
+    src="images/i_p050b.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 16.</span>—Hewitt’s wide-bore gas valves.</p>
+     </div>
+
+<p>Fig. 16 shows the Hewitt type of inhaler. The calibre of the orifices
+through which respiration takes place is greater than in the Barth
+three-way tap, and to that extent this type of valve<span class="pagenum" id="Page_51">[51]</span> is to be
+preferred. Although differently arranged exactly the same possibilities
+are present in it.</p>
+
+<p>The <i>facepiece</i> is sometimes made of celluloid with an inflatable
+rubber edging. The object of this type of facepiece is that the
+colour of the lips may be appreciated by the anæsthetist during the
+administration. The preferable plan is to make the whole facepiece of
+rubber with an inflatable border. Such a facepiece made by a good maker
+will last many years, and is much more stable and reliable than its
+celluloid competitor.</p>
+
+
+<h3><b>The Care of the Nitrous Oxide Apparatus.</b></h3>
+
+<p>This is a matter of considerable moment, particularly to those who do
+not use their apparatus every day. After use, the valves, facepiece,
+and bag should be disconnected from each other, all moisture wiped away
+from the bright parts, and the bag hung up with its open end downwards,
+and preferably in a warm room. If re-breathing has been extensively
+practiced it is well to wash the bag out with some carbolic lotion
+before hanging it up. The rubber valves in the valvepiece are liable
+to lose their elasticity, particularly if kept in a cold place after
+becoming damp. From time to time the valve piece should be taken to
+pieces, the valves carefully dried in front of a warm fire and powdered
+over with a little talc.</p>
+
+
+<h3><b>Administration.</b></h3>
+
+<p>Most commonly nitrous oxide is administered to a patient sitting in a
+chair. Care should be taken that the respiration of the patient shall
+not be obstructed by tight clothing round the throat or chest, and
+that the head and neck are neither unduly flexed nor extended upon the
+shoulders. The patient should not have any solid food for two hours
+before the anæsthetic. At the last moment he should be instructed to
+empty his bladder. Artificial dentures if present should be removed,
+and, if the anæsthetic is being given for the purpose of the extraction
+of a<span class="pagenum" id="Page_52">[52]</span> tooth, it will be necessary before applying the facepiece to
+insert between the teeth a dental prop. (See Fig. <a href="#i_p022">6.</a>) Standing to the
+left and slightly behind the patient the anæsthetist’s first step is to
+secure good apposition between facepiece and face. This is best done by
+working from above downwards: that is to say, secure first a good fit
+at the bridge of the nose, and then approximate the remainder of the
+rim of the facepiece to the cheeks and lower jaw. During this stage the
+indicator of the tap is kept at “Air.”</p>
+
+<p>Working with the left foot the administrator now opens the head of one
+of the cylinders with the foot key. It is wise first to have loosened
+this with a hand key, and leave it just “on the swing,” otherwise
+one’s boots are apt to suffer! Gas is allowed to flow into the bag
+until it is partially, but by no means tightly distended. The patient
+is instructed to breathe naturally and easily, and during the whole
+process the anæsthetist should converse with him in a quiet easy way.
+The tap is now turned to “valves” and the patient begins to inspire
+the gas, a supply of which is allowed to flow steadily from cylinder
+into bag. After a few breaths of the gas, when the sensibilities of
+the patient are a little dulled, it is wise to allow the gas to flow
+a little more freely and to distend the bag. This exercises upon the
+patient a slight <i>positive pressure</i>, which has been proved
+both experimentally and practically to increase the rapidity of the
+absorption.<a id="FNanchor_1" href="#Footnote_1" class="fnanchor">[1]</a> The valves are left in operation for some thirty or
+forty seconds, after which time the supply of gas should be cut off
+and the tap be pushed over to the position of “no valves” for further
+twenty seconds. This should be ample to secure full gas anæsthesia.</p>
+
+<p><i>The phenomena</i> seen in nitrous oxide anæsthesia are so different
+from those of any other that a few words must be said about them.
+Within a few seconds of the inhalation beginning, the colour of<span class="pagenum" id="Page_53">[53]</span> the
+patient shows evidence of the presence of the gas in his blood. The
+normal complexion changes first to a dull pink, and very rapidly to the
+definite blue of cyanosis. The <i>eye symptoms</i> are of the utmost
+value. Very early the pupil begins to dilate, and the eyeball tends
+during the first twenty or thirty seconds to rotate as if the patient
+were looking for some object in his field of vision. In full anæsthesia
+the eyeball, however, comes to rest, usually pointed downwards. The
+pupil is widely dilated, the conjunctival reflex is almost or even
+entirely abolished, but the corneal reflex is still brisk. <i>The
+respiration</i> tends to become steadily deeper and more frequent, and
+in the later stages stertor at least, if not stridor usually develops.
+<i>The muscles</i> under ordinary nitrous oxide anæsthesia are rarely
+entirely relaxed, but the limbs hang motionless, and it is only if an
+attempt be made to move them into some abnormal position, that one
+appreciates the persistence of muscular tone.</p>
+
+<p>A phenomenon peculiar to nitrous oxide anæsthesia is observed in its
+deepest stage. Designated as <i>jactitation</i>, it consists in a
+tremor beginning in the limbs, but spreading from them to the trunk if
+its development is allowed to proceed. It is a finer movement than that
+described under “ether tremor” (page 38), and wholly different in type
+from the athetosis referred to on page 38. Jactitation is almost wholly
+an asphyxial phenomenon, and is therefore definitely an indication
+that the process of oxygen starvation has been carried as far as is
+permissible.</p>
+
+<p><i>The signs of fully developed nitrous oxide anæsthesia</i> then are:—</p>
+
+<div class="blockquot">
+
+<p>1. Deep regular snoring respirations.</p>
+
+<p>2. Dilated pupils.</p>
+
+<p>3. Rotation of the eyeball downwards.</p>
+
+<p>4. Loss of conjunctival but persistence of corneal reflex.</p>
+
+<p>5. A colour of the skin definitely blue, but not blackish blue.</p>
+
+<p>6. The commencement of jactitations.</p>
+</div>
+
+<p><span class="pagenum" id="Page_54">[54]</span></p>
+
+<p><i>The signs of overdose</i> are:—</p>
+
+<div class="blockquot">
+
+<p>1. An enormously dilated pupil not re-acting to light.</p>
+
+<p>2. Loss of corneal reflex.</p>
+
+<p>3. A blackish blue colour.</p>
+
+<p>4. Jactitations fully developed.</p>
+
+<p>5. Failing respirations.</p>
+</div>
+
+<p>The final arrest of respiration in nitrous oxide anæsthesia is usually
+painfully sudden. Upon the respiratory side the only warning is one or
+two gasps, and even that is sometimes absent. The paralysed pupil and
+the jactitations are the most useful signs of overdose.</p>
+
+<p>The above, then, may be taken as an account of what one expects to see
+in a normal gas anæsthesia during the induction stage. For the great
+majority of cases, nitrous oxide is given for the purpose of rendering
+painless the extraction of a tooth, and it is, in this large class of
+case, the induction stage only which need be considered. It requires
+only some fifty to sixty seconds to bring the patient to the stage
+described under the heading “fully developed anæsthesia” and when that
+has been attained, the mask may be removed and the operation begun.
+From the moment of removal of the mask, however, it must be noted that
+the patient begins to breathe fresh air and to eliminate the N<sub>2</sub>O.
+The period of anæsthesia available to the surgeon or dentist during
+which he must perform the operation, is therefore very small. In thirty
+seconds the patient has frequently recovered sufficiently to begin
+to feel pain, and it is rare to secure more than forty-five or fifty
+seconds by the use of a single dose of nitrous oxide.</p>
+
+
+<h3><b>Nitrous Oxide and Air.</b></h3>
+
+<p>If the nature of the operation does not necessitate the removal of the
+mask from the face, it is possible to maintain nitrous oxide anæsthesia
+for some considerable time. The exact length of that time varies a good
+deal with two factors—the type of patient and<span class="pagenum" id="Page_55">[55]</span> the experience of the
+administrator. Heavily built muscular patients are not easily dealt
+with by prolonged gas anæsthesia (unless with admixture of oxygen as
+explained in chapter viii.) Of far greater importance, however, is the
+other factor. The student can easily be taught to give a single dose
+of gas for the extraction of a tooth, or the momentary incision of an
+abscess. He will, however, be wise to secure a good deal of practice in
+that class of work before attempting to prolong gas anæsthesia for more
+than a minute or two.</p>
+
+<p>With reasonable skill and experience and the utmost care, it is,
+however, perfectly possible to prolong nitrous oxide anæsthesia for
+periods of five, ten, or even fifteen minutes in the average healthy
+patient. As soon as the signs of full anæsthesia appear, the valve
+tap is pushed back to “air” for the space of one inspiration and
+one expiration, and then at once pushed back to “no valves.” By
+this manœuvre, one inspiration of air is permitted to the patient,
+whose colour at once shows amelioration, or at any rate no further
+progression of cyanosis. The admission of air is repeated every third,
+fourth, or at most fifth respiration. After the first minute or so
+of this cycle of events, it is obvious that the contents of the bag
+will be composed of a mixture of nitrous oxide, air, and CO<sub>2</sub> in
+proportions quite impossible to calculate. It is therefore best to
+push the indicator to “valves,” and allow the bag to be emptied by the
+suction of the patient’s inspirations. The cylinder head is then opened
+by the turning of the foot-key, and the bag filled again with gas. The
+cycle of “air” and “no valves” is then begun again for another minute
+or so.</p>
+
+<p>It must be understood that by this process, it is not to be expected
+that an ideal anæsthesia can be produced. Some movement of the patient
+will not improbably take place when sensitive structures are cut or
+handled by the surgeon, and at no time will the muscles be entirely
+relaxed. Such an anæsthesia is therefore only suitable for a limited
+class of case, but does admirably for,<span class="pagenum" id="Page_56">[56]</span> say, opening an abscess,
+exploring its interior, and removing from it a sequestrum or an easily
+found foreign body. During his service in Macedonia the author had not
+at his disposal any of the appliances later to be described under the
+heading of nitrous oxide and oxygen, and found “gas and air” a most
+useful form of anæsthesia for the requirements of military surgery as
+seen in a Base Hospital, under active service conditions.</p>
+
+
+<h3><b>Contra-indications to the Use of Pure Nitrous Oxide Gas.</b></h3>
+
+<p>In the healthy subject, there is no safer anæsthetic than nitrous oxide
+when administered properly and limited to its proper province.</p>
+
+<p>From the account given of the physiological action of the gas it will,
+however, be obvious to the student that in a limited class of case its
+use is not permissible. Such cases fall into two categories.</p>
+
+<p><i>Firstly, cases in which an asphyxial element already exists will
+have their condition greatly aggravated by the substitution of N<sub>2</sub>O
+for the oxygen in their blood.</i>—Already caught in the vicious
+circle of asphyxia, nitrous oxide would but push them deeper into the
+vortex. Examples of such cases are patients suffering from tumours or
+inflammatory swellings in the neck which are pressing upon the air
+passages. In passing, one may note that it might be the desire of the
+surgeon to submit an individual case falling into this group to the
+operation of tracheotomy for the immediate relief of the condition. The
+short space of time required for this little operation might well tempt
+the unwary to choose nitrous oxide as the anæsthetic, and in point of
+fact such an error of judgment has more than once been made with fatal
+results.</p>
+
+<p><i>Secondly, no patient suffering from any condition which will be
+aggravated by a sudden rise of blood pressure, should be submitted to
+nitrous oxide undiluted by oxygen.</i>—Examples of such conditions are
+cases of <i>dilated right heart</i> with weakened cardiac musculature.</p>
+
+<p>Such hearts could not be expected to work against a peripheral<span class="pagenum" id="Page_57">[57]</span>
+resistance suddenly raised, say, from 120 mm. of Hg, to 180 or even
+200 mm.—figures well within the possible in deep gas anæsthesia.
+Similarly, so great an increase of pressure would be dangerous to
+a patient suffering from an <i>aneurysm</i>, or from <i>extensive
+arterio-scelorosis</i> with high blood pressure.</p>
+
+<p>It will be noted that the above warnings are limited to the use of pure
+nitrous oxide, that is, N<sub>2</sub>O unmixed with oxygen. The extent to which
+the dangers referred to can be met by the admixture of oxygen in the
+manner to be described in the next chapter is largely a matter of the
+skill and experience of the administrator.</p>
+
+
+<h3><b>Nasal Methods.</b></h3>
+
+<p>The object of using this route is to be able to continue the
+administration throughout the period in which the dentist is doing his
+work. The essentials of a suitable apparatus are:—</p>
+
+<div class="blockquot">
+
+<p>1. A malleable nosepiece which can be closely adapted to the
+nose.</p>
+
+<p>2. Two supply pipes from bag to nosepiece.</p>
+
+<p>3. Some means of admitting air to the stream of gas.</p>
+
+<p>4. A two-gallon bag.</p>
+
+<p>5. A supply of gas.</p>
+
+<p>6. A mouth cover with an expiratory valve only.</p>
+</div>
+
+<p>The patient is instructed to breathe in through the nose, but to
+expire through the mouth. The gas is supplied under some pressure and
+the mouth cover ensures that no air is inspired by that route. Some
+patients find it easier to conduct both inspiration and expiration
+through the nose, and for their benefit an expiratory valve is also
+provided in the nosepiece. After unconsciousness has supervened, nearly
+all patients begin to-and-fro nasal breathing. The mouth cover may then
+be removed, and if it be desired to economise gas, the expiratory valve
+in the nosepiece may be thrown out of action.</p>
+
+<p><span class="pagenum" id="Page_58">[58]</span></p>
+
+  <div class="figcenter" id="i_p058" style="max-width: 406px">
+     <img
+    class="p1"   
+    src="images/i_p058.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 17.</span>—Ash’s Modification of Paterson’s
+Nasal Gas</p>
+     <p class="p0 sm"><span class="smcap">Description</span>:—A—Nose-Cap Attachment with Stopcock for Air
+and Gas, and with Inspiratory and Expiratory Valves and Shutter.
+B—Nose-Cap. C—Sliding Clip on India-rubber Tubings. D—Bifurcated
+Mount. E—Bag Mount. F—Gas Bag Compressor. G—Gas Bag. H—India-rubber
+Tubing. MC—Mouth Cover. This is fitted with an expiratory valve, and
+should be used at the same time as the Nose-Cap. By using the two
+together patients are more quickly anæsthetised than they would be if
+only the Nose-Cap were used, and the Nitrous Oxide is economised.</p>
+     </div>
+
+<p><span class="pagenum" id="Page_59">[59]</span></p>
+
+<p>Air must be admitted in limited quantity through the tap after
+the first thirty seconds or so; by a judicious regulation of this
+mechanism, anæsthesia may be prolonged for five or ten minutes.
+Facility with nasal gas comes only after some considerable practice.</p>
+
+<p>Fig. 17 shows Ash’s No. 3 Patented Nasal Inhaler, which admits of
+Air or Gas being administered either by the Naso-Oral Method, or by
+to-and-fro nasal breathing. <i>Air</i> only is admitted when the
+Shutter A is open and turned to the right as far as it will go.
+<i>Nitrous Oxide</i> is admitted when the Shutter A is open and turned
+to the left as far as it will go, and the patient will breathe it
+in-and-out through the nose. <i>For the Nasal Oral Method</i>, close
+Shutter A and turn it to the left as far as it will go. This will cause
+the patient to inhale through the nose and exhale through the mouth.</p>
+
+<p>Nasal attachments are provided with most of the gas-oxygen apparatuses
+mentioned in the next chapter. With them good results can be obtained
+with much greater ease.</p>
+
+<p>For a more detailed account of nasal methods, the student is referred
+to works devoted entirely to Dental Anæsthesia.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_60">[60]</span></p>
+
+<h2>CHAPTER VIII.<br>
+<span class="subhed"><b>NITROUS OXIDE AND OXYGEN.</b></span></h2></div>
+
+<p>The account given in the previous chapter of anæsthesia by nitrous
+oxide and air will have convinced the student that it is a somewhat
+inelegant method with a limited sphere of usefulness. The reason is
+obvious. In atmospheric air, oxygen exists only in the proportion
+of about one to four of nitrogen. To sustain life it is therefore
+necessary to admit to the anæsthetic mixture an amount of air which
+leaves too little room for the anæsthetic factor—nitrous oxide. If,
+however, pure oxygen be used, the nitrous oxide is diluted to a much
+less degree, and far better results are obtained.</p>
+
+<p>The exact scope for gas-oxygen anæsthesia cannot at present be defined
+with certainty. The work of Crile, and the experience of the war have
+done much to enlarge it. We may say that the following are definite
+indications for its use:—</p>
+
+<div class="blockquot">
+
+<p>(1) Minor operations lasting 5–15 minutes, particularly if
+performed on out-patients.</p>
+
+<p>(2) Operations of any variety upon the subjects of severe shock.</p>
+
+<p>(3) Operations upon patients suffering from acute sepsis.</p>
+
+<p>(4) Operations repeated upon the same subject at short intervals.</p>
+</div>
+
+<p>As regards (3) and (4), the lack of toxic properties in nitrous oxide
+gas, and the rapidity with which it is eliminated, give it a tremendous
+advantage over ether or chloroform. To men with shattered bones and
+extensive damage to soft tissues, badly infected with sepsis, who
+required repeated opening up of pockets, changing of gauze packs, etc.,
+the advantage of gas-oxygen over ether was<span class="pagenum" id="Page_61">[61]</span> evident, and was easily
+appreciated by the patients themselves during the late war.</p>
+
+<p>There are, however, certain <i>drawbacks</i> to the method which must
+be appreciated—</p>
+
+<div class="blockquot">
+
+<p>(1) The necessary plant is heavy, bulky, and costly; it cannot
+be easily transported.</p>
+
+<p>(2) The running cost is high as compared with ether or
+chloroform.</p>
+
+<p>(3) It has been said by some that gas-oxygen can only be given
+by an expert. That is a statement too extreme, in the author’s
+opinion. Certainly, of all anæsthetics it is the most difficult
+to give successfully. Adequate study and proper teaching by an
+expert are required, but given these two helps, any one can soon
+learn to administer gas-oxygen for minor surgery. Considerably
+more experience is, however, necessary before the beginner
+should give it for an abdominal section.</p>
+</div>
+
+
+<h3><b>Apparatus.</b></h3>
+
+<p>A good gas-oxygen apparatus is necessarily rather complicated. The
+machines in the market are numerous, and of the most diverse external
+appearance. Certain broad principles, however, underlie all the
+machines, and it is to be hoped that some one of them will before long
+become practically the standard. Once that is effected, hospitals and
+nursing homes could be expected to provide them. So long as every
+anæsthetist asks for a different machine, they certainly never will do.
+A good machine must provide means for the following:—</p>
+
+<div class="blockquot">
+
+<p>(1) <i>An even flow</i> of both gases under perfect control.</p>
+
+<p>(2) <i>A percentage of Oxygen</i> in the mixture rising at the
+will of the administrator from 2 to 15 or 20.<a id="FNanchor_2" href="#Footnote_2" class="fnanchor">[2]</a> To meet this
+requirement it is not necessary that any indicator should be<span class="pagenum" id="Page_62">[62]</span>
+provided which shows with mathematical precision what percentage
+of oxygen is being given. The colour of the patient tells us at
+once if too much or too little oxygen is being supplied, and all
+we need in the apparatus is some mechanism whereby we can tell
+approximately to what extent we are increasing or decreasing the
+percentage.</p>
+
+<p>(3) <i>Positive Pressure.</i>—If the pressure at which the
+gases are supplied to the patient can be raised a little above
+that of the ordinary atmosphere, absorption is increased and a
+deeper anæsthesia produced. In the author’s view, this is an
+essential point in a good instrument.</p>
+
+<p>(4) <i>Re-breathing.</i>—To supply the whole volume of gases
+required for inspiration during a long operation is costly and
+quite unnecessary. Yet that is what is being done if the whole
+administration is conducted upon the “valvular” principle.
+Moreover, a prolonged inhalation upon the valves tends to remove
+a great deal of CO<sub>2</sub> from the patient’s blood and tissues
+(<i>see</i> Chap. <span class="allsmcap">IV</span>.). Periods of partial or complete
+re-breathing do much to deepen respiration, and reduce the cost
+of the anæsthetic.</p>
+
+<p>(5) <i>Warming the Gases.</i>—While not essential, this is
+certainly an advantage.</p>
+
+<p>(6) <i>Addition of Ether Vapour to the mixture.</i>—Gas-oxygen
+even well given is hardly capable of reducing to quiescence
+very robust people, unless the oxygen percentage is kept to an
+undesirably low level. The merest trace of ether vapour as an
+adjunct is a great assistance during the stages of the operation
+where very sensitive structures such as the parietal peritoneum
+are being handled. The more experienced the anæsthetist, the
+less will he require such assistance.</p>
+</div>
+
+<h3><b>Hewitt’s Apparatus.</b></h3>
+
+<p>This, with the exception of one designed by Dr Guy and the author,
+and described on page 130, is the only machine with any<span class="pagenum" id="Page_63">[63]</span> pretence to
+portability by hand. It does not satisfy all the requirements above
+referred to, but the fact that it was the first practicable means
+introduced in this country to give gas-oxygen entitles it to full
+description. (<i>See</i> Fig. <a href="#i_p063">18</a>.)</p>
+
+  <div class="figcenter" id="i_p063" style="max-width: 390px">
+     <img
+    class="p1"   
+    src="images/i_p063.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 18.</span>—Hewitt’s gas oxygen apparatus.</p>
+     </div>
+
+<p>Essentially it consists of the following:—</p>
+
+<p><span class="pagenum" id="Page_64">[64]</span></p>
+
+<div class="blockquot">
+
+<p>(1) A supply of nitrous oxide and oxygen in separate cylinders.
+Hewitt’s own stand held two of nitrous oxide and one of
+oxygen.<a id="FNanchor_3" href="#Footnote_3" class="fnanchor">[3]</a></p>
+
+<p>(2) Rubber pipes of supply for each of the two gases. For
+convenience, it is sometimes arranged that one of these shall
+run inside the other.</p>
+
+<p>(3) Two 2-gallon bags. Nitrous oxide is led into the one, oxygen
+into the other. The mouth of <i>each</i> bag is guarded by an
+inspiratory valve.</p>
+
+<p>(4) The mixing chamber. Upon the surface of this are marked
+successively: “Air,” “N<sub>2</sub>O,” “O<sub>2</sub>, 1 2 3 4 5 6 7 8 9 10.”
+As the indicator is pushed from “air” to “N<sub>2</sub>O,” the patient
+begins to inhale nitrous oxide only, but as it travels into the
+numerals 1, 2, etc., a proportion of oxygen is added.</p>
+
+<p>Immediately below the mixing chamber is the <i>expiratory
+valve</i>.</p>
+
+<p>(5) Lastly, there is the <i>facepiece</i>, identical with that
+used for pure nitrous oxide.</p>
+</div>
+
+<p>It would be fallacious to suppose that the numerals 2, etc., on the
+dial represent accurately the percentage of oxygen yielded by the
+instrument when the indicator points to one of these figures, nor
+did Hewitt ever make such a claim. What the figures do represent is
+a number of holes in the wall of the mixing chamber, opposite to the
+aperture from the oxygen bag, which are uncovered one by one as the
+indicator moves over. The amount of oxygen which enters into the mixing
+chamber is regulated by the number of these holes uncovered, and also
+by the tension of the oxygen bag. If the figure on the dial is to be
+even a rough index of the actual percentage of oxygen present in the
+mixture, it is necessary<span class="pagenum" id="Page_65">[65]</span> to keep the tension reasonably constant,
+<i>i.e.</i> to regulate the flow of oxygen from the cylinder by
+manipulation of the foot key. In a brief administration for, say,
+a dental case, this is not necessary. It is sufficient to fill the
+oxygen bag once, and then turn off the supply. If, however, a long
+administration is required, a constant flow of oxygen of just the
+requisite amount must be secured.</p>
+
+
+<h3><b>Administration.</b></h3>
+
+<p>Put the lever at “air,” and fill up each bag to an equal and moderate
+degree of distention. Adapt the facepiece accurately to the patient’s
+face, and then push the lever to “N<sub>2</sub>O”. After a few inhalations,
+move to 2 of oxygen; regulate the flow of nitrous oxide from the
+cylinder so that the N<sub>2</sub>O bag remains slightly distended. Gradually
+move the indicator along the numerals until the figure 6 or 8 is
+reached at the end of about a minute or a minute and a half. Women and
+children require more oxygen than men. The former are easily cyanosed;
+if the latter are fed too generously with oxygen, they are apt to
+become excited. Take as your guide to the amount of oxygen required the
+colour of the patient, the type of respiration, and the size of the
+pupil.</p>
+
+<p>The <i>colour</i> aimed at can only be learnt by experience, but is
+best described as a dull pink.</p>
+
+<p><i>The Type of Respiration.</i>—Too little oxygen leads to stertor and
+even stridor; too much oxygen, to a light almost noiseless respiration,
+which to the experienced ear is the certain precursor of a stage of
+excitement. Such a stage is clear evidence of too much oxygen having
+been given.</p>
+
+<p><i>The pupil</i> should not be dilated to anything like the degree
+seen with undiluted nitrous oxide. A moderate distention only is to be
+desired.</p>
+
+<p><i>Full Anæsthesia</i> should be reached in 100–120 seconds. It is
+marked by:—</p>
+
+<p><span class="pagenum" id="Page_66">[66]</span></p>
+
+<div class="blockquot">
+
+<p>(1) Dull pink complexion; (2) full respiratory movements with
+a stertor not exceeding that of gentle snoring; (3) eyeballs
+rotated downwards; (4) moderately dilated pupils; (5) loss of
+conjunctival reflex; (6) corneal reflex present but not very
+active.</p>
+</div>
+
+<p>If the object be the removal of a tooth, the mask may now be removed,
+and the dentist may rely upon a period of anæsthesia somewhat longer
+than that furnished by pure nitrous oxide. He ought to secure
+approximately one minute in which to do his work.</p>
+
+<p>Anæsthesia by this apparatus may however be prolonged for an
+indefinite time if desired. In order to maintain the patient in the
+condition described above, it will be necessary gradually to increase
+the supply of oxygen. For this purpose Hewitt added to his mixing
+chamber a supplementary oxygen supply giving 10 or 20 volumes of
+oxygen. As a matter of fact, all the necessary supply can be got
+through the original ten holes <i>if the tension in the oxygen bag
+be increased</i>. The regulation of all this requires, of course,
+considerable practice and experience.</p>
+
+<p>The signs upon which we rely for warning that the supply of oxygen is
+insufficient to keep the patient safe, are chiefly the colour of the
+face, which must not pass from dull pink to blue, and the size of the
+pupil.</p>
+
+  <div class="figcenter" id="i_p067" style="max-width: 750px">
+     <img
+    class="p1"   
+    src="images/i_p067.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 19.</span>—Diagrams to illustrate action of (A)
+Hewitt (B) Teter gas oxygen apparatus. Note that in A the mouths of
+both bags are guarded by valves of inspiration, while in B the oxygen
+bag only possesses it.</p>
+     </div>
+
+
+<h3><b>Deficiencies of Hewitt’s Apparatus.</b></h3>
+
+<p>These are chiefly two:—</p>
+
+<div class="blockquot">
+
+<p>(1) There is no means of producing <i>positive pressure</i>. Any
+attempt to distend the nitrous oxide bag beyond a certain point
+simply leads to escape of the gas through the mixing chamber and
+out of the expiratory valve even during inspiration. To this
+defect especially must we attribute the fact that an anæsthesia
+deep enough for abdominal section is difficult to secure with
+the Hewitt instrument.</p>
+
+<p><span class="pagenum" id="Page_68">[68]</span></p>
+
+<p>(2) There is no means of securing <i>re-breathing</i>. The whole
+administration must of necessity be conducted “upon the valves.”
+This latter fault is remedied by the modification introduced by
+<i>Burns</i>, who took away the inspiratory valve from the mouth
+of the N<sub>2</sub>O bag, and fitted a cap over the expiratory valve
+which could be rotated so as to throw the valve out of action.
+The author first met this modification at a Base Hospital in
+France, and found it a great improvement upon the original
+instrument. It is, however, only an imperfect attempt to adopt
+Teter’s chief principle.</p>
+</div>
+
+
+<h3><b>The Teter and Allied Machines.</b></h3>
+
+<p>The rapid spread of nitrous oxide and oxygen anæsthesia in the
+U.S.A. brought forward a number of machines of which Teter’s was the
+forerunner; the other well-known machine of the group is the Clarke.
+They differ in principle from the Hewitt apparatus in that they permit
+re-breathing and the use of positive pressure. Diagrammatically, the
+two are contrasted in Fig. 19.</p>
+
+  <div class="figcenter" id="i_p068" style="max-width: 583px">
+     <img
+    class="p1"   
+    src="images/i_p068.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 20.</span>—Details of the Clarke Expiratory
+Valve. In the position of the lever marked “open” the valve lifts
+easily and widely, and the breathing will be purely valvular: in the
+position marked “half open,” the valve lift is diminished, and the
+breathing is partly valvular, partly to-and-fro. In the position
+“closed” re-breathing only is possible.</p>
+     </div>
+
+<p>The key to Teter’s advance is his removal of the inspiratory valve from
+the mouth of the nitrous oxide bag, and his substitution for Hewitt’s
+rubber expiratory valve, of a <i>rigid</i> valve, the lift of which
+can be diminished or entirely abolished, at will (<i>see</i> Fig.
+<a href="#i_p068">20</a>). By damming, as it were, the flow from the expiratory valve, the
+administrator can oblige the patient to practise a certain amount of
+re-breathing, and, if he keeps up a free flow of the gases, he<span class="pagenum" id="Page_69">[69]</span> can
+develop a pressure in the nitrous oxide bag definitely exceeding that
+of the atmosphere.</p>
+
+<p>Teter also introduced into his apparatus a means to warm the gases, and
+to add a little ether vapour to the mixture when required.</p>
+
+  <div class="figcenter" id="i_p069" style="max-width: 326px">
+     <img
+    class="p1"   
+    src="images/i_p069.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 21.</span>—The Clark gas oxygen machine.</p>
+     </div>
+
+<p>The Clarke machine is similar in principle to the Teter, but makes a
+strong point of the intimate mixture of the two gases produced in the
+mixing chamber which occupies the centre of the apparatus (Fig. 21).</p>
+
+<p><span class="pagenum" id="Page_70">[70]</span></p>
+
+<p>In both these machines, it will be observed, the two bags for N<sub>2</sub>O
+and O<sub>2</sub> respectively are attached to the stand, and the mixed gases
+are led to the patient by a pipe of wide bore. When re-breathing
+occurs, it must therefore be up and down this pipe, but the width of
+the bore seems to obviate any disadvantage which theoretically might be
+expected from this form of respiration.</p>
+
+  <div class="figcenter" id="i_p070" style="max-width: 474px">
+     <img
+    class="p1"   
+    src="images/i_p070.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 22.</span>—Marshall’s sight-feed gas-oxygen
+apparatus. Of the two glass bottles the one to the left is the
+sight-feed, that to the right the ether chamber.</p>
+     </div>
+
+<p>In the experience of the author and of many other anæsthetists, very
+good results can be obtained from either of these machines.</p>
+
+
+<h3><b>Sight Feed Machine.</b></h3>
+
+<p>In the author’s opinion, machines based upon this principle are likely
+to take a prominent place in the future of gas-oxygen.<span class="pagenum" id="Page_71">[71]</span> Fig. 22
+explains the simple mechanism. Each gas is led through a tube dipping
+into water contained in the sight feed mixing chamber. The ends of
+the pipes are open, and on the sides of each pipe also are a number
+of holes. If the pressure at which either gas is delivered is small,
+bubbles will be seen ascending towards the surface of the water from
+the upper holes only. The greater the pressure, the further down the
+pipe does the gas carry before all of it escapes through a hole, and
+one can therefore get an accurate estimate of the pressure from the
+number of holes through which the bubbles are seen escaping.</p>
+
+<p>Upon the surface of the water, the two gases meet and enter into
+mixture and are conveyed away by the third pipe which, of course, does
+not dip into the water.</p>
+
+<p>Once the eye of the anæsthetist is trained to its use, this is a very
+simple means of gauging the relative proportions of oxygen and nitrous
+oxide which are being delivered, and manipulation of the cylinder heads
+combined with visual inspection of the sight feed enable one to strike
+the right proportions very easily. The nitrous oxide is usually kept at
+a constant pressure sufficient to ensure bubbles, not only from all the
+side holes, but also a few from the open end of the tube. The oxygen
+pressure is begun at the point where there is a little bubbling from
+the top hole only, and is gradually increased until there is a full
+supply from two holes, occasionally a little even from a third.</p>
+
+<p>Messrs Coxeter have recently brought out two sight feed machines
+designed by Mr Leonard Boyle and Dr Geoffrey Marshall, of which the
+latter is shown in Fig. 22. This apparatus may be put up in either
+portable form or a larger type for use in hospitals. An ether chamber
+is provided for use when necessary in either type.</p>
+
+<p>As originally introduced, the remainder of the apparatus consisted
+simply of an ordinary two gallon bag, Barth 3-way tap, and rubber
+facepiece. With such an appliance, it is not possible<span class="pagenum" id="Page_72">[72]</span> to secure
+“positive pressure, a point which the author brought to the notice
+of the makers. Messrs Coxeter are willing to supply a facepiece and
+expiratory valve which obviate this defect, being supplied with a mica
+expiratory valve the lift of which can be controlled. There should be
+no inspiratory valve.</p>
+
+
+<h3><b>Administration of Gas-oxygen for the purposes of Major Surgery.</b></h3>
+
+<p>The patient is prepared with the same scrupulous care as if ether
+or chloroform is to be administered. Half an hour before operation,
+morphia gr. ⅙ and atropine gr. ¹⁄₁₀₀ are given hypodermically. The
+anæsthetist before beginning administration, must look over the
+apparatus most carefully and satisfy himself that every part of it is
+in perfect order, and that a sufficient supply of both gases is at hand.</p>
+
+<p>The inhalation is begun by the use of nitrous oxide alone, given “on
+the valves,” and at no great pressure. After a few breaths, oxygen
+is added very guardedly, the proportion being steadily raised during
+the first two minutes: after that point, a further increase will not
+be necessary until several more minutes have elapsed. The pressure at
+which the mixture is being given is also steadily increased and should
+reach the maximum permissible within a few minutes. A useful plan
+is to allow the flow of gases to remain constant, but to close the
+expiratory valve at frequent intervals for about forty to sixty seconds
+at a time. During this period of complete re-breathing the tension in
+the supplying bag will of course rise, falling again slightly when the
+expiratory valve is allowed once more to come into action. As soon as
+the tension falls appreciably, the valve is again closed down.</p>
+
+<p>It is wise, particularly in one’s early days, to give a trace of ether
+vapour during the latter part of the induction stage, and to maintain
+it until the operation is well under way. Once the<span class="pagenum" id="Page_73">[73]</span> anæsthetist is
+satisfied that the narcosis is proving deep enough for the purposes
+of the operation, the ether may be shut off and will probably not be
+required again.</p>
+
+<p>Remember that <i>depth</i> of anæsthesia can be secured in three
+ways—(1) cutting down the oxygen percentage; (2) increasing the
+tension of the mixed gases; (3) adding a little ether. Of these, No. 1
+is most undesirable, and if carried to the least excess over a period
+of more than a minute or two may lead to an accident. No. 3 is the
+means for the beginner to rely upon, until he learns the judicious
+and skilful use of No 2. The anæsthetist who is learning the method
+of anæsthesing must resolve that nothing shall tempt him to overstep
+the stage of dull pink colour, and moderate pupils. If with gas-oxygen
+alone, he cannot get a satisfactory anæsthesia without resorting to
+oxygen starvation, let him not be ashamed to turn on his ether.</p>
+
+<p>Abdominal relaxation sufficiently complete to permit the surgeon to
+explore the abdominal cavity with ease, is not readily secured by
+gas-oxygen in a patient of robust type. Fortunately, it is the weakly
+or the severely shocked who really <i>need</i> this form of anæsthesia,
+and in them abdominal relaxation is fairly easily obtained.</p>
+
+<p>Professor Crile, as has already been explained, does not rely upon
+the inhalational anæsthetic alone. He infiltrates each layer of the
+parietes with novocain, thus producing a local anæsthesia. If this
+method be faithfully carried out by the surgeon, a most complete
+relaxation of the muscles can be secured.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_74">[74]</span></p>
+
+<h2>CHAPTER IX.<br>
+<span class="subhed"><b>ETHER.</b></span></h2></div>
+
+<p>The drug commonly known as ether and otherwise described as ethylic
+ether or sulphuric ether, has a chemical formula (C<sub>2</sub>H<sub>5</sub>)<sub>2</sub>O.
+It is a transparent colourless fluid with a specific gravity of ·720
+to ·723. A brand much used in the States has an S.G. of ·713 only, a
+point which is greatly emphasised by its supporters, who claim that it
+volatises quicker and therefore is more powerful in action. The author
+has in actual practise not found much difference between this brand and
+any good British one.</p>
+
+<p>Ether is highly inflammable and volatilises readily at ordinary
+room temperatures. Its boiling point is 96° to 98° Fahr. Whether
+evaporating from a fabric such as gauze, or from bulk in a jar, ether
+cools very rapidly, and the fall in temperature soon reduces the
+ease of its volatisation. This point is of some practical importance
+in anæsthetics, and some years ago the author made a number of
+observations, hitherto unpublished, with a view of ascertaining some
+definite facts in this connection. His results will be found in
+Appendix <span class="allsmcap">I</span>.</p>
+
+<p><i>Ether vapour</i> is heavy—two and a half times heavier than air.
+It therefore tends in a room to flow towards the floor, and to remain
+for some time unmixed with the general atmosphere. Since it is highly
+explosive, this constitutes a definite danger if any naked light or
+open fire is present. Everyone who handles ether should bear in mind
+these physical peculiarities of its vapour.</p>
+
+<p>Ether is affected by prolonged exposure to bright sunlight, and also by
+prolonged bubbling through it of air, nitrous oxide, or oxygen. Ether
+which has been subjected to any of these<span class="pagenum" id="Page_75">[75]</span> measures should be inspected
+before being put back into reserve, and if any brown discoloration
+is noticed, it should either be sent to the hospital laboratory for
+redistillation, or presented to the theatre sister for use as a
+cleaning agent. Such contributions are always gratefully received.</p>
+
+<p>Most of the ordinary impurities of ether are acid in reaction, while
+ether itself is absolutely neutral. Any specimen which turns litmus
+paper red should be sent to the laboratory for examination.</p>
+
+
+<h3><b>Sources of Supply.</b></h3>
+
+<p>Ethylic alcohol may be prepared either from ethyl alcohol or from
+methylated spirits. In the former case it carries, however, the cost
+of the duty imposed upon potable spirit, and since perfectly good
+anæsthetic ether can be prepared from the latter source, it is waste of
+money to use the more expensive article.</p>
+
+
+<h3><b>Physiology.</b></h3>
+
+<p>Ether acts upon the nervous system like other anæsthetics: as compared
+with chloroform, however, the stage of excitation of each centre
+before its paralysis is apt to be marked. There is, therefore, in some
+subjects, a greater tendency to struggle; healthy subjects properly
+handled do not show much evidence of irritation of the cerebrum. All,
+however, show some evidence of stimulation of the respiratory centre,
+which is not prolonged. <i>Prolonged deep and rapid respiration under
+ether is due to other causes than the action of the drug itself.</i> It
+is of course seen in “closed ether,” but the active agent is excess of
+CO<sub>2</sub>, not ether.</p>
+
+<p>The working margin of safety in ether, <i>i.e.</i> the stage between
+loss of spinal reflexes and the poisoning of respiratory centre is much
+wider than in chloroform.</p>
+
+<p>Some experiments of Waller made many years ago showed that upon nerve
+tissue, ether acts much less powerfully than chloroform: in the
+proportion, he found, of one to seven or eight.<span class="pagenum" id="Page_76">[76]</span> These laboratory
+results have received entire confirmation by later workers who have
+estimated the actual vapour strength required of either drug to produce
+or maintain anæsthesia. Roughly, to induce anæsthesia, we require 2 per
+cent. chloroform, or 16 to 18 per cent. of ether (<i>see</i> Appendix
+II.).</p>
+
+
+<h3><b>The Circulation.</b></h3>
+
+<p>The first effect of ether is a temporary stimulation of the heart,
+which beats more rapidly and more strongly, thus raising the blood
+pressure. This effect is not very prolonged; like all other drug
+stimulation, it is followed by depression. In the healthy subject
+properly anæsthetised, such depression is very moderate in degree, and
+in a normal administration it is probable that the heart, after the
+first few minutes, is acting very much at its normal speed and force.
+Ether is, however, a marked vaso-dilator, and the net result upon blood
+pressure is a slight fall after the first few minutes.</p>
+
+<p>If the method in use is “closed,” the pressure remains slightly raised
+for some considerable time, usually throughout the administration. The
+slight anoxaemia induces a vaso-constriction; and the CO<sub>2</sub> excess, in
+the view of Henderson (<i>see</i> page <a href="#Page_10">10</a>), maintains a good return of
+venous blood to the heart and a satisfactory cardiac output. For a note
+of certain blood changes resulting from ether and other anæsthetics
+(<i>see</i> Appendix III.).</p>
+
+
+<h3><b>Respiratory System.</b></h3>
+
+<p>In addition to the effect upon the medullary centre already referred
+to, ether effects the respiratory tract more profoundly than other
+anæsthetics. The mucous membranes are irritated, and in some cases
+there is a great outpouring of mucous. Though usually limited to the
+upper part of the tract (nose, pharynx, and trachea), the irritation
+sometimes extends deeply into the chest, affecting even the small
+bronchioles. These unpleasant effects of<span class="pagenum" id="Page_77">[77]</span> ether are in the great
+majority of cases, quite transient: after the first ten minutes no
+addition to the secretions is noticed. In a minority, however, the
+effect persists, the whole chest is filled with moist sounds, and
+persistence with the drug is impossible.</p>
+
+<p><i>The kidneys</i> are always slightly irritated by ether, and if they
+are or recently have been subject to inflammatory disease, a very acute
+exacerbation is apt to follow the use of the drug. In the healthy
+kidney this is not to be feared, nor does it seem to be an appreciable
+danger where one kidney is sound, even if the other is the seat of
+gross organic disease necessitating its drainage or removal.</p>
+
+  <div class="figcenter" id="i_p077" style="max-width: 277px">
+     <img
+    class="p1"   
+    src="images/i_p077.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 23.</span>—Clover’s ether inhaler, with nitrous
+oxide attachment.</p>
+     </div>
+
+
+<h3><b>Methods of Administration.</b></h3>
+
+<p>Many methods have been tried, but those which at present hold the field
+are—</p>
+
+<div class="blockquot">
+
+<p>(1) Closed Ether.</p>
+
+<p>(2) Open Ether, more properly called the Perhalation Method.</p>
+
+<p>(3) The “Vapour” Method.</p>
+
+<p>(4) The Rectal Method (Gwathmey’s oil-ether).</p>
+
+<p>(5) The Intratracheal Method, described separately in Chapter
+<span class="allsmcap">X</span>.</p>
+</div>
+
+<p><span class="pagenum" id="Page_78">[78]</span></p>
+
+  <div class="figcenter" id="i_p078" style="max-width: 495px">
+     <img
+    class="p1"   
+    src="images/i_p078.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 24.</span>—Diagram of a vertical section through
+the middle of Clover’s Inhaler. A. shows the ether dome; B. Central
+tube removed from apparatus.</p>
+     </div>
+
+
+<h4>(1) <b>Closed Ether.</b></h4>
+
+<p>The two inhalers originally brought out for this were Clover’s in
+London, and Ormsby’s in Dublin. At a later date Hewitt’s “wide bore”
+modification of the Clover was introduced.</p>
+
+<p>(<i>a</i>) <i>The Clover instrument</i> (see Fig. <a href="#i_p077">23</a>)<a id="FNanchor_4" href="#Footnote_4" class="fnanchor">[4]</a> consists
+of a face-piece, a dome-shaped ether chamber, and a one-gallon bag,
+usually attached to the top of the ether chamber by a <b>T</b>-shaped
+tube. The details of the method by which the amount of ether inhaled
+by the patient is graduated are best appreciated by unscrewing the<span class="pagenum" id="Page_79">[79]</span>
+milled head at the top of the dome, and withdrawing the tube which runs
+through it (<i>see</i> Fig. <a href="#i_p078">24</a>). In the tube will be found two slots,
+one about half an inch above the other, and each extending for half the
+circumference of the tube. Between these two slots the tube is divided
+by a diaphragm. In any case, therefore, air passing up or down the tube
+must pass in and out of these slots.</p>
+
+<p>Now turn to the tubular space left in the dome piece, and examine
+visually and with the finger its interior. On the one side of its
+middle will be found two slots leading into the circular ether chamber
+which occupies a large part of the dome. On the other side will be
+found a small cavity, as deep from above downwards as the two slots
+combined, but <i>not</i> communicating with the ether chamber. It is
+obvious that with the tube inside, if this cavity is opposite the slots
+in the tube, air will pass up the tube out of one slot and back into
+the other, without coming into contact with the ether at all. If on the
+other hand the slots in the tube are opposite the slots in the ether
+chamber, the air passes over the surface of the contained ether, and
+volatises some of it.</p>
+
+<p>Intermediate positions of the tube give a condition where part only
+of the air passes over the ether. The indicator attached to the tube,
+combined with the figuring “O, one, two, three, full,” to be found
+on the outside of the base of the dome, shows at any moment what
+proportion of the air is passing into the ether chamber.</p>
+
+<p>To use the instrument, fill the metal measure provided with ether,
+withdraw the stopper from the ether chamber, and pour in the ounce
+and a half of ether which the measure contains. Replace the stopper,
+and blow through the tube to expel any ether vapour which may have
+appeared in it. Leave the rubber bag at first unattached: the patient
+will feel more comfortable if during the first minute the top of the
+tube is open. With the indicator at 0 adapt the face-piece to the face
+and allow<span class="pagenum" id="Page_80">[80]</span> the patient to breathe up and down the tube. By rotating
+the dome, ether is then gradually turned on, until the figure two
+is reached in the first minute. The indicator is then slipped back
+nearly to zero for a second, and the rubber bag slipped on during
+an <i>expiration</i>: it must be moderately inflated to supply the
+requisite volume of air for respiration.</p>
+
+  <div class="figcenter" id="i_p080" style="max-width: 379px">
+     <img
+    class="p1"   
+    src="images/i_p080.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 25.</span>—Hewitt’s wide-bore ether inhaler.</p>
+     </div>
+
+<p>The rotation of the dome is again begun and the indicator is made to
+travel away from the zero, until at the end of about five minutes, it
+reaches “full.” After the first few minutes, it will be necessary to
+give an occasional breath of fresh air, otherwise an undesirable degree
+of cyanosis will result, but it must be done with great discretion, or
+struggling will ensue. At the end of about five minutes, anæsthesia
+should be fully established. A<span class="pagenum" id="Page_81">[81]</span> little extra ether is then poured
+into the chamber, the indicator pushed back to about “two” and the
+administration continued. One breath of fresh air is given in every
+three or four. Spells may be given with the bag off altogether, but
+during such periods the indicator will require to be advanced a little,
+and refills of ether provided more frequently than would be necessary
+if the bag were on.</p>
+
+
+<h5><b>Hewitt’s-wide-bore.</b></h5>
+
+<p>The principle of this is identical with that of the Clover, but the
+channels being wider, there is less mechanical interference with the
+ingress and egress of air. The actual construction differs also, in
+that to turn on the ether, instead of rotating the dome, one moves the
+indicator (<i>see</i> Fig. <a href="#i_p080">25</a>). The instrument certainly gives results
+a little better than those obtainable by the Clover, but it is heavier,
+and rather more bulky.</p>
+
+
+<h5><b>Ormsby’s Inhaler (<i>See</i> Fig. <a href="#i_p081">26</a>).</b></h5>
+
+<p>This consists of a facepiece, a cage made of wire or thin steel slips
+and containing a sponge; and lastly, a one gallon bag which fits
+over the cage. In the face-piece is an air vent, which can be either
+entirely closed, partially or entirely opened.</p>
+
+  <div class="figcenter" id="i_p081" style="max-width: 298px">
+     <img
+    class="p1"   
+    src="images/i_p081.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 26.</span>—Ormsby’s Inhaler. The cage for the
+sponge does not show in the figure, it projects upwards from the
+bag-mount, and is therefore enclosed in the bag.</p>
+     </div>
+
+<p>To use the instrument, take out the sponge and warm it either by
+wringing it out of hot water, or better by leaving it a few minutes on
+the top of a hot steriliser. Push it back into the<span class="pagenum" id="Page_82">[82]</span> cage, open the air
+vent fully, and holding the inhaler upside down, pour on to the sponge
+a measure full (about half an ounce) of ether. Tell the patient to
+inhale deeply, and then catch the resulting expiration in the bag by
+quickly adapting the facepiece to the face at the appropriate second.</p>
+
+<p>After a few seconds, begin to close the air vent, when it will be
+found that the bag begins to wax and wane with each expiration and
+inspiration respectively. After the first three minutes, the inhaler
+must be removed, more ether poured in, the air vent opened again
+partially, and the inhaler again applied to the face. After full
+anæsthesia is induced, the air vent may constantly be left partially
+open.</p>
+
+<p><i>N.B.</i>—It must be observed that the air vent is not valved: it is
+merely an opening through which part of the respired air may pass in
+and out without going near the ether sponge.</p>
+
+<p>In actual practice, the induction stage of closed ether is almost
+invariably assisted by using either nitrous oxide, or a small dose of
+ethyl chloride as a preliminary: these methods are described in Chapter
+<span class="allsmcap">XV</span>.</p>
+
+<p>The question now arises, what <i>scope</i> is to be assigned in modern
+anæsthesia, to closed-ether methods. Formerly a large proportion of
+anæsthesias, long or short, were conducted by the closed method, and
+while the greater number of anæsthetists no longer utilise them to the
+same extent as formerly, they may still be regarded as of the utmost
+value in a limited class of cases. They are speedy in action, powerful
+enough to overcome the most refractory patient, and with reasonable
+skill very safe. On the other hand, the anæsthesia obtained is not
+of the most desirable type. There is a great deal of salivation and
+mucous secretion from the respiratory mucous membranes; the respiratory
+movements are deeper than in open methods, from the excess of CO<sub>2</sub>
+present in the blood, and this leads to a good deal of heaving of
+the abdominal wall, which may<span class="pagenum" id="Page_83">[83]</span> be most troublesome to the surgeon
+if he is opening or closing that cavity. Moreover, after their use
+more headache, malaise, and vomiting occur than after open-ether, and
+perhaps a little more tendency to bronchitis or pneumonia. For these
+reasons, many anæsthetists and surgeons now object to their use in
+abdominal surgery, though some still adhere to them for the induction
+stage, passing to the open method when the patient is once well under.</p>
+
+
+<h4><b>(2) Open Ether.</b></h4>
+
+<p>As already explained the strictly accurate term for this is
+Perhalational Ether, but so cumbersome a terminology stands small
+chance of general acceptance.</p>
+
+
+<h5><b>Apparatus.</b></h5>
+
+<p>The essential points in a proper outfit have already been explained
+(<i>see</i> page <a href="#Page_28">28</a>) and are all well met by the mask and ether dropper
+introduced by Mr Bellamy Gardner (<i>see</i> Fig. <a href="#i_p083">27</a>). The mask is
+covered with from twelve to sixteen layers of gauze, and lies on the
+gauze ring, shown in the Fig. <a href="#i_p084a">28</a><span class="allsmcap">A</span>, which completes the fit
+between face and facepiece. The dropper fits into the ordinary six
+ounce dispensary bottle: the long arm dips into the ether, the short
+one allows air to enter the bottle to replace the ether used. A dropper
+can also be improvised by<span class="pagenum" id="Page_86">[86]</span> using a cork with slots cut at each side
+and with a gauze or wool wick inserted along one of these. The author
+finds these uncertain in their action, however: with Gardner’s dropper,
+a steady flow of <i>drops</i> of ether slow or fast as required, can
+always be obtained once the student has acquired the knack of using the
+appliance.</p>
+
+  <div class="figcenter" id="i_p083" style="max-width: 650px">
+     <img
+    class="p1"   
+    src="images/i_p083.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 27.</span>—Bellamy Gardner’s (<span class="allsmcap">A</span>) open
+ether mask; (<span class="allsmcap">B</span>) ether dropper.</p>
+     </div>
+
+  <div class="figcenter" id="i_p084a" style="max-width: 402px">
+     <p class="p1 center smaller"><span class="smcap">Fig. 28.</span></p>
+     <img
+    class="p0"   
+    src="images/i_p084a.jpg"
+     alt="">
+     <p class="p0 center smaller"><i>A.</i>—Open ether. Ready to begin.</p>
+     </div>
+
+  <div class="figcenter" id="i_p084b" style="max-width: 367px">
+     <img
+    class="p1"   
+    src="images/i_p084b.jpg"
+     alt="">
+     <p class="p0 center smaller"><i>B.</i>—Open ether. Condensing towel in position.</p>
+     </div>
+
+  <div class="figcenter" id="i_p085a" style="max-width: 401px">
+     <img
+    class="p1"   
+    src="images/i_p085a.jpg"
+     alt="">
+     <p class="p0 center smaller"><i>C.</i>—Open ether. Correct method of holding mouth and jaw.</p>
+     </div>
+
+  <div class="figcenter" id="i_p085b" style="max-width: 467px">
+     <img
+    class="p1"   
+    src="images/i_p085b.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><i>D.</i>—Open ether. Alternative method of holding mask. The
+towel and gauze have been removed so as to show the tilting of
+the mask which this method is liable to cause.</p>
+     </div>
+
+<p>To Mr Bellamy Gardner’s outfit, the author adds a folded towel, pinned
+at one corner, so as to form a short cone. The base of this cone
+embraces the mask and face; through its upper apperture the anæsthetic
+is dropped on to the mask. The cone can be rotated into the position
+most convenient for this purpose in any given position of the patient’s
+head (Fig. 28).</p>
+
+
+<h5><b>Problems of the Induction Period.</b></h5>
+
+<p>Open-ether is not a powerful anæsthetic, just not powerful enough for
+one to be sure that one can induce full anæsthesia with it alone, in a
+powerful subject. The reason for this is shown in Appendix II, and may
+be here condensed by explaining that some 18 per cent. to 20 per cent.
+of ether vapour is required to induce anæsthesia, while it is not easy
+to get more than 14 per cent. off an open mask. How is this situation
+to be met?</p>
+
+<p>Reference has already been made to one solution of the problem. <i>A
+closed ether method may be used for induction</i>, and this practice is
+widely used. The author does not often adopt this course, fearing that
+the undesirable features of closed ether may persist even after the
+change to an open method has been made.</p>
+
+<p>Another possibility even more widely favoured is to use <i>chloroform
+as the inducing agent</i>, and only to turn to ether when full
+anæsthesia is obtained. To this plan the author is strongly opposed. It
+exposes the patient to the risks of the induction stage of chloroform
+which are much greater than those of the later stages. Moreover, to
+develop the full advantages of open-ether, a preliminary hypodermic
+of morphia is essential, and the<span class="pagenum" id="Page_87">[87]</span> drawbacks of chloroform <i>plus</i>
+morphia are elsewhere mentioned (page 43).</p>
+
+<p>The use of a <i>mixture of chloroform two parts, ether three parts</i>,
+presents the same disadvantage, but in a degree so much smaller that
+in powerful or alcoholic patients, the author believes this to be the
+method of choice (<i>see</i> Chapter xiv.).</p>
+
+<p><i>Dr Silk</i> has recently suggested another plan. He has sought to
+make open-ether easy for the non-expert with a view of encouraging the
+wider use of so valuable a method. For this purpose he advocates the
+admixture of one part of chloroform in thirty-two of ether (a dram of
+chloroform in four ounces of ether). This is to be given in exactly the
+same way as perhalational ether, and will, Silk says, give a type of
+anæsthesia, and a degree of safety, identical with those of pure ether.
+The author’s experience with Silk’s mixture is too limited to enable
+him to offer any opinion upon its merits.</p>
+
+<p>Lastly, there remains the plan of using <i>ether as the main inducing
+agent</i>, but assisting its action by the intermittent and most
+guarded addition of small quantities of C<sub>2</sub>E<sub>3</sub> mixture. This is
+the author’s “stock” method; but in teaching it to students, too
+much emphasis cannot be laid upon the small quantities of chloroform
+mixture required or <i>permissible</i>. <i>As a consequence of the
+perhalational method here advocated, every drop of chloroform which
+appears on the mask will when volatilised, give a very much higher
+percentage of CHCL<sub>3</sub> vapour in the inspired air, than the same
+quantity exhibited on the ordinary open chloroform mask.</i> Once the
+student has grasped this essential fact, ordinary care and intelligence
+will enable him to guard against a danger which is only existent if
+unappreciated.</p>
+
+
+<h5><b>The Administration.</b></h5>
+
+<p>For many of the hints given in this section the author is<span class="pagenum" id="Page_88">[88]</span> indebted to
+Dr W. J. Ferguson of New York, and Dr Hornabrook of Melbourne.</p>
+
+<p>Success in inducing with open-ether is attained only by attention to a
+number of small details. The student who thinks that some of these are
+too trifling for his notice is usually the man who informs you that
+induction by open-ether is impossible, the fact really being that he
+has not taken the trouble to learn, or has never had proper tuition.
+The following are the points demanding attention:—</p>
+
+<div class="blockquot">
+
+<p>1. Always give a dose of morph-atropine or other narcotic, half
+to three-quarters of an hour beforehand.</p>
+
+<p>2. See that the patient is comfortable on the table. Prop up his
+head and shoulders a little with pillows. In powerful subjects
+Hornabrook tilts the whole table down at the foot-end, for a few
+degrees.</p>
+
+<p>3. Adhere strictly to perhalation and to the drop method. You
+will never induce with open-ether if the whole volume of the
+respired air does not pass through the gauze.</p>
+
+<p>4. Chat to the patient as long as consciousness can possibly
+persist. Tell him he is doing very well. Don’t shout complicated
+instructions at him as to how to breathe: it annoys and muddles
+him.</p>
+
+<p>5. When the gauze ring and the mask are in position, allow one
+or two drops of ether to fall on the mask, then pause: in a few
+seconds the mild ether vapour so formed will soothe the upper
+respiratory tract, and prepare it for the stronger vapours yet
+to come. This does not waste time—it saves it.</p>
+
+<p>6. When the administration is again begun, attend closely to
+the rate of dropping. At first not more than one drop in three
+or four seconds is wanted. The full rate of dropping cannot be
+attained for at least ninety seconds.</p>
+
+<p>7. Give no mixture for the first ninety seconds; thereafter some
+five to ten drops every half minute or every twenty seconds<span class="pagenum" id="Page_89">[89]</span>
+according to type of patient. Have the mixture bottle handy so
+that no time is wasted in changing bottles. Stop the addition of
+mixture as soon as full anæsthesia is attained.</p>
+
+<p>8. Slip the folded towel over the mask and tuck its base well
+round the chin and face. Do this only after the first two
+minutes have elapsed.</p>
+
+<p>9. As soon as the neck muscles are relaxed, turn the patient’s
+head over to one side, and let the hands assume the position
+described in Chapter iii. and illustrated in Fig. 28<span class="allsmcap">C</span>.</p>
+
+<p>10. The student is warned to discourage the too early attentions
+of the nurse or house-surgeon. These officials are naturally
+anxious to “get the patient ready for the Chief” and are
+apt to start “cleaning up” before the patient has lost all
+consciousness. A man who is doing his level best to go to sleep,
+derives neither pleasure nor profit from a wholly unexpected dab
+of ice-cold methylated spirit upon his umbilicus.</p>
+</div>
+
+<p>By the use of the method here advocated, induction is singularly easy
+and successful in good subjects. The struggling stage is either not
+represented at all, or appears only in the form of the lifting of
+a limb and a slight occasional pause or catch in respiration. Full
+anæsthesia is often announced audibly, by the commencement of a gentle
+“blowing.” Once it is heard, the anæsthetist may rest assured that a
+workable level of anæsthesia is either present or not far off.</p>
+
+
+<h5><b>Amounts of Ether required.</b></h5>
+
+<p>If the above instructions are followed, the amount of ether required
+is not excessive. Anæsthesia is attained after the use of about 1½ to
+2 ounces of ether and one or two drams of mixture. The next forty to
+fifty minutes demand about another four or five ounces of ether; no
+mixture at all. Some practice, is required before these small figures
+are attained. The more practice, the less ether is required.</p>
+
+<p><span class="pagenum" id="Page_90">[90]</span></p>
+
+
+<h3>III.—<span class="smcap"><b>Vapour Anæsthesia.</b></span></h3>
+
+<p>In a sense, all forms of ether anæsthesia are vapour methods, but
+in all the forms so far described, the patient has to vapourise the
+drug for himself: in a true vapour anæsthesia this is done for him,
+and the mixture of air and ether vapour propelled towards him. One
+of the keenest advocates of this method is Dr Gwathmey, of New York.
+He lays great stress also upon the necessity of warming the vapour,
+claiming that this measure will prevent the loss of heat to the patient
+incidental to the warming up in the air passages of the cold vapour
+usually supplied by other methods; but the results of the laboratory
+experiments upon which Gwathmey founded his case are inapplicable to
+the human subject, in that they were performed upon dogs and cats,
+which lose heat largely from the mouth and air stream. Man is not a
+hairy animal, and transacts most of his thermolysis through the medium
+of his skin. None the less, warming the vapour of ether has value since
+the process removes some of the irritant effects so marked in the case
+of cold ether vapour.</p>
+
+
+<h4><b>Apparatus for the Vapour Method.</b></h4>
+
+<p>In 1913, Karl Connell described such an apparatus, which was then in
+use at the Roosevelt Hospital, New York. The ether was vapourised by
+dropping it into a warm chamber. Air was pumped into the chamber, and
+carried the ether vapour in known percentage, and at known pressure as
+shown by gauges. Such mechanism is ideal, but would certainly be rather
+costly. Its great value was that it informed us with certainty what
+proportions of ether in the atmosphere were necessary to induce and
+maintain anæsthesia (<i>see</i> Appendix II.).</p>
+
+<p>A simple mechanism was brought out shortly afterwards by Dr Shipway, of
+Guy’s, and is known as Shipway’s warmed Ether.</p>
+
+<p>It consists essentially of the following parts (<i>see</i> Fig. <a href="#i_p091">29</a>):—</p>
+
+<p><span class="pagenum" id="Page_91">[91]</span></p>
+
+<div class="blockquot">
+
+<p>(1) A small hand bellows (B).</p>
+
+<p>(2) An ether bottle, with tube for delivery of air stream
+dipping deeply into the fluid: the exit tube of course does not
+dip in. The bottle stands in a metal pan in which water at about
+75° Fahr. is to be placed (E).</p>
+
+<p>(3) A thermos flask (W) in which is a metal tube (U). The
+etherised air passes along this tube, and picks up heat from its
+walls. The thermos is filled with water at about 180° Fahr.</p>
+</div>
+
+  <div class="figcenter" id="i_p091" style="max-width: 512px">
+     <img
+    class="p1"   
+    src="images/i_p091.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 29.</span>—Shipway’s warmed ether vapour
+apparatus.</p>
+     </div>
+
+<div class="blockquot">
+
+<p>(4) A mask upon which a towel or gauze is to be stretched: the
+rubber tube bringing the air and ether is brought through the
+covering material and delivers the anæsthetic vapour in the
+region of the mouth.</p>
+
+<p><span class="pagenum" id="Page_92">[92]</span></p>
+
+<p>(5) Additional to the above, there may be added a small
+chloroform bottle (C). In specimens of the instrument containing
+this convenience, there has, of course, to be a regulating tap
+(T) at the head of the ether bottle, which will divert more or
+less of the air stream towards the chloroform.</p>
+</div>
+
+<p>This little machine, somewhat resembling a cruet stand in its
+appearance was widely used in France. Owing to the kindness of
+the Edinburgh Red Cross Committee, one was provided for the Base
+Hospital with which the author proceeded to Salonika, where he used
+it extensively. The impression of it formed by himself and others
+was that it was peculiarly easy to maintain with it a steady level
+of anæsthesia. It had, however, no claim to banish post-anæsthetic
+bronchitis and pneumonia, of which in spite of much anxious care and
+thought, a fair number of cases were seen during the winter time
+(<i>see</i> page <a href="#Page_151">151</a>).</p>
+
+<p>In using the machine, it is necessary to remember that from the
+physical point of view, one is providing from the machine a small part
+only of the total volume of air required by the patient.</p>
+
+<p>The bellows are quite small: one squeeze of the hand will not supply
+more than about the equivalent in volume of one or two fluid ounces.
+The larger part of the volume required by the patient has to be
+obtained from the general atmosphere, so that the percentage of ether
+which may be as high as 25 in the exit tube, will be greatly lowered by
+the time it reaches the patient’s respiratory tract.</p>
+
+<hr class="tb">
+
+<p>The actual strength of ether breathed by the patient will depend upon:—</p>
+
+<div class="blockquot">
+
+<p>1. The force and frequency with which the pump is compressed.
+(<i>N.B.</i> It is of course useless to pump during expiration).</p>
+
+<p>2. The depth of ether in the bottle.</p>
+
+<p><span class="pagenum" id="Page_93">[93]</span></p>
+
+<p>3. The temperature of the water bath in which the ether bottle
+stands. The warm water should only be put in at the last moment
+before starting, otherwise very strong ether vapour will collect
+on the surface of the ether, and the first puff of the bulb will
+expel a highly irritant vapour towards the patient.</p>
+</div>
+
+<p>With specimens of this machine which have the addition of the
+chloroform bottle, it is perfectly possible to conduct even the
+induction stage of anæsthesia; a mere trace of chloroform vapour will
+be sufficient. It is unnecessary to give detailed instructions for the
+use of the machine. A preliminary consideration of the above physical
+facts, together with a little cautious practice, will enable the
+student rapidly to acquire facility with the method.</p>
+
+
+<h3>IV.—<span class="smcap"><b>Rectal Etherisation.</b></span></h3>
+
+<p>For such operations as the removal of jaw or tongue there are obvious
+advantages in being able to introduce ether vapour to the blood per
+rectum, since the mouth and air passages are thereby left free for the
+attention of the surgeon.</p>
+
+<p>Many years ago this was attempted by vapourising ether and propelling
+the vapour through a tube high up into the rectum. This method was
+abandoned, as it led to a good deal of inflammatory trouble afterwards.
+Recently, Dr Gwathmey suggested a new method of utilising the rectal
+route which has largely overcome this objection.</p>
+
+
+<h4><b>Gwathmey’s Oil Ether Method.</b></h4>
+
+<p>This consists in passing into the rectum a mixture of olive oil and
+ether. The bowel is first carefully washed out, and an hour before
+operation, the patient receives a hypodermic of morphia, gr. ⅙;
+atropine, gr. ¹⁄₁₂₀. A suppository of chloretone gr. v is also passed
+into the rectum to act as a local sedative. Half-an-hour later, the
+patient is put into the left lateral position, a soft catheter<span class="pagenum" id="Page_94">[94]</span>
+attached to a funnel is passed some six inches up the rectum, and the
+mixture of oil and ether poured into the funnel. It is wise to take at
+least five minutes to introduce the whole dose.</p>
+
+<p>The following table shows the dosage required:—</p>
+
+<table class="smaller" style="max-width: 40em">
+  <tr>
+    <td class="ctrtrbl">Age of Patient.</td>
+    <td class="ctrtrb">Strength of<br>Ether in<br>Mixture.</td>
+    <td class="ctrtrb">Quantity of Mixture required.</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">Under 6 years</td>
+    <td class="ctrr">50%</td>
+    <td class="chtr">One ounce to each 20 pounds body<br>weight (no preliminary morphia)</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">6 to 12 years</td>
+    <td class="ctrr">55% to 65%</td>
+    <td class="ctrr">Do.&emsp;&emsp;&emsp;&emsp;do.</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">12 to 15 years</td>
+    <td class="ctrr">Do.</td>
+    <td class="chtr">One ounce to each 20 pounds body<br>weight (but use ¹⁄₁₂ gr. morphia)</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrbl">16 years and<br>upwards</td>
+    <td class="ctrrb">75%</td>
+    <td class="chtrb">One ounce to each 20 pounds body<br>weight with ⅙ gr. morphia as a<br>preliminary</td>
+  </tr>
+</table>
+
+<p>In practice then, for the ordinary adult, one uses eight ounces of the
+mixture, six ounces of which are pure ether. The oil and ether require
+to be shaken together, but remain blended long enough for introduction.</p>
+
+<p>In five or ten minutes, the patient begins to feel a rather pleasing
+numbness and tingling in the lower, and later the upper extremities,
+and drops quietly to sleep in about twenty minutes. In a large
+proportion of cases, it is necessary to deepen the anæsthesia by the
+use of the open mask for a few minutes, but once a deep anæsthesia has
+been thus obtained, the absorption from the rectum will balance the
+loss in expiration and maintain a good anæsthesia for three quarters of
+an hour at least.</p>
+
+<p>On return to bed of the patient, the nurse passes two tubes placed side
+by side, as high into the rectum as she can; the end of a Higginson
+syringe is inserted into one of them, and a considerable quantity of
+soap and water is pumped gently into the bowel,<span class="pagenum" id="Page_95">[95]</span> escaping down the
+second tube. The washing must be continued until all smell of ether
+is removed. Finally the soapy water itself is washed away by a little
+saline.</p>
+
+<p>Unless there be some pre-existing local inflammatory disease of the
+rectum (in which case the method should not be used), there are no
+unpleasant sequelæ after oil ether. The chief objection to the method
+is the amount of labour thrown on the nursing staff, which is so
+considerable as to bar it from adoption as a routine. This should not,
+however, be allowed to prevent its use in the limited number of cases
+in which it is strongly indicated. These are:—</p>
+
+<div class="blockquot">
+
+<p>(1) Panic-struck cases who cannot face the ordeal of ordinary
+methods.</p>
+
+<p>(2) Nose, throat, and tongue operations where intratracheal
+ether is not available.</p>
+</div>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_96">[96]</span></p>
+
+<h2>CHAPTER X<br>
+<span class="subhed"><b>INTRATRACHEAL INSUFFLATION OF ETHER</b></span></h2></div>
+
+<p>Intratracheal insufflation consists in driving a current of air under
+pressure, through a tube introduced by way of the mouth and larynx,
+deeply into the trachea. The current of air which is continuous,
+returns between the tube and the wall of the trachea, and escapes
+through the mouth and nose.</p>
+
+
+<h3><b>Certain Physical Considerations.</b></h3>
+
+<p>The work of Meltzer and Auer has demonstrated that this insufflation of
+air into the trachea under adequate pressure ventilates the pulmonary
+alveoli, and enables the normal diffusion of gases to be carried out
+for many hours, independently of all respiratory movements. If the
+air in its passage under pressure is made to pass through a chamber
+containing ether, we are enabled to introduce into the pulmonary
+alveoli, ether vapour of varying strength, and, by this means, to
+maintain surgical anæsthesia.</p>
+
+<hr class="tb">
+
+<p><span class="smcap">The Actual Process of External Respiration</span> consists in the
+absorption of oxygen from the alveoli into the blood of the lung
+capillaries, and the elimination of carbon dioxide from the lung
+capillaries into the alveoli. The oxygen has to be brought from the
+outside to the alveoli, and the carbon dioxide has to be conducted
+from the alveoli to the outside. Between the outside and the alveoli
+is the long airshaft, consisting of mouth and nose, pharynx, larynx,
+trachea, bronchi and bronchioles. In natural respiration the conduction
+of oxygen inwards, and of carbon<span class="pagenum" id="Page_97">[97]</span> dioxide outwards, is carried through
+by a complicated pumping mechanism. In ordinary inhalation anæsthesia,
+this mechanism is entrusted with the task of introducing ether vapour
+into the alveoli.</p>
+
+<p>In intratracheal insufflation the work of this natural pumping
+apparatus is taken over by an artificial mechanism. In considering the
+justification for this, the following points are to be noted:—</p>
+
+<div class="blockquot">
+
+<p>(1) The patient is unconscious—not naturally so as in
+sleep—but unnaturally as the result of drugs; there is
+therefore a probability that the elaborate natural mechanism
+may not work smoothly—especially is there a danger that the
+free airway may be interfered with. Intratracheal insufflation
+obviates this danger.</p>
+
+<p>(2) By means of the artificial mechanism, air is brought with
+some force to the mouth of the bronchi, and thus a more rapid
+and more powerful diffusion of gases takes place.</p>
+
+<p>(3) The mechanism ensures the maintenance of a current of air
+blowing forcefully from the trachea and larynx through the
+pharynx, mouth and nose. This re-current continuous air-stream
+effectively prevents the entrance of blood or any infectious
+material into the bronchi and air cells, and thus the danger of
+septic lung troubles is obviated.</p>
+
+<p>(4) In certain intrathoracic operations the normal respiratory
+mechanism is deliberately interfered with. Intratracheal
+insufflation by the constant maintenance of sufficient positive
+pressure, prevents or regulates the collapse of the lung
+which occurs when the thorax is opened, and thus obviates the
+necessity for the somewhat elaborate positive and negative
+pressure cabinets and masks which had been devised for
+intrathoracic operations.</p>
+
+<p>(5) Incidentally it may be noted that intratracheal insufflation
+of air provides us with an excellent means for performing<span class="pagenum" id="Page_98">[98]</span>
+artificial respiration. Many instances have now been recorded
+of its utility in this respect. Dr Elsberg records the case
+of a patient who had taken morphia with suicidal intent, on
+whom artificial respiration by this method was kept up for 12
+hours, without any respiratory movements taking place, recovery
+ultimately ensuing.</p>
+</div>
+
+
+<h3><b>The Apparatus.</b></h3>
+
+<p>This consists of (<i>see</i> Fig. <a href="#i_p098">30</a>):—</p>
+
+<div class="blockquot">
+
+<p>1. Instrument for producing air current (A).</p>
+
+<p>2. Ether chamber and various regulating taps (B).</p>
+
+<p>3. Device for warming vapour (C).</p>
+
+<p>4. Safety valve (D).</p>
+
+<p>5. Manometer (E).</p>
+
+<p>6. Intratracheal catheter, with rubber tubing linking up the
+various parts of the apparatus (H).</p>
+</div>
+
+  <div class="figcenter" id="i_p098" style="max-width: 750px">
+     <img
+    class="p1"   
+    src="images/i_p098.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 30.</span> Diagram of intratracheal apparatus.</p>
+     </div>
+
+<p>1. <span class="smcap">The Air Current</span> is obtained either by means of an ordinary
+glass-blower’s foot bellows, or an electric motor may actuate a
+rotatory blower which produces a current of air. The blower may be made
+to rotate at a speed varying from 50 to 1000 revolutions per minute
+(<i>see</i> Fig. <a href="#i_p099">31</a>).</p>
+
+<p>The foot bellows is simple and inexpensive, and there is no reason why
+it should not be efficient. The electrically rotated blower is more
+efficient, ensures a smoother air current, and saves much labour.</p>
+
+<p><span class="pagenum" id="Page_99">[99]</span></p>
+
+<p>2. <span class="smcap">The Ether Chamber.</span>—Ether vapour may be produced by
+either of two methods. Fig. 32 shows Kelly’s instrument where air is
+blown over the surface of a considerable quantity of liquid ether. Dr
+Meltzer<a id="FNanchor_5" href="#Footnote_5" class="fnanchor">[5]</a> maintains that the effectiveness of the etherization is
+proportional to the diameter of the ether bottle. In this connection
+it may be well to recall certain points pertinent to the subject of
+etherization. A satisfactory etherization depends on the establishment
+in the blood and tissues of an ether tension of definite strength.
+Boothby<a id="FNanchor_6" href="#Footnote_6" class="fnanchor">[6]</a> states that this tension should correspond to about 15 per
+cent. of ether vapour in the alveolar cells. “If when this tension has
+been established, less than 15 per cent. ether vapour is administered,
+outward diffusion occurs from the tissues and blood to the air and the
+anæsthesia becomes lighter.”</p>
+
+  <div class="figcenter" id="i_p099" style="max-width: 589px">
+     <img
+    class="p1"   
+    src="images/i_p099.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 31.</span>—Electric blower to supply current of
+air for intratracheal anæsthesia.</p>
+     </div>
+
+  <div class="figcenter" id="i_p100" style="max-width: 699px">
+     <img
+    class="p1"   
+    src="images/i_p100.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 32.</span> Kelly’s intratracheal apparatus.</p>
+     </div>
+
+<p><span class="pagenum" id="Page_100">[100]</span></p>
+
+<p>In an apparatus such as we are describing the strength of the ether
+vapour depends on and is influenced by a variety of factors, among
+which the following may be specially noted:—</p>
+
+<div class="blockquot">
+
+<p>(<i>a</i>) <i>The diameter of the ether chamber.</i>—The larger
+the diameter the stronger will be the ether vapour. The chamber
+is generally kept two-thirds full: the less the empty space in
+the chamber the stronger will be the vapour.</p>
+
+<p>(<i>b</i>) <i>The rapidity of the air-current.</i>—The larger
+the amount of air passing over the ether the more rapid will be
+the vapouration, with the result that the temperature of the
+liquid ether will rapidly fall and the strength of the ether
+vapour in the air will be correspondingly lowered.</p>
+
+<p>(<i>c</i>) <i>The temperature of the liquid ether.</i>—The
+higher the temperature of the liquid ether the stronger will be
+the percentage of ether vapour in the air. If the ether chamber
+is placed in a bath of water which is maintained steadily at an
+adequate temperature and if the rate of the air flow remains
+constant, a constant strength of ether vapour will be given off.
+It is well in this connection to remember that the<span class="pagenum" id="Page_101">[101]</span> boiling
+point of ether is low and that a very high percentage of ether
+vapour is readily obtained if the temperature in the water
+bath is allowed to rise beyond 80°F. For further information
+regarding ether percentages <i>see</i> Appendix I and II.</p>
+</div>
+
+<p>Such an instrument as Kelly’s requires at its head a <i>regulating
+tap</i>, movement of which is capable of diverting part of the air
+stream direct to the patient without coming in contact with the surface
+of the ether. In this way the maximum strength of vapour may be diluted
+as and when required.</p>
+
+<p>In Fig. 33 is shown Shipway’s instrument. Here the drug is dripped
+into a chamber, the floor of which is kept warm. The ether volatilises
+at once and the vapour is carried away by the air stream passing
+through the chamber. The strength of ether vapour in this instrument is
+regulated solely by the rate of drip which is in complete control of
+the administrator.</p>
+
+<p>Whichever method of making ether vapour is utilised the instrument
+should be capable of producing a maximum at least of 15 per cent. to 18
+per cent., and means must be provided to reduce this percentage at will.</p>
+
+<p>3. <span class="smcap">Device for Warming Vapour.</span>—It is doubtful if the warming
+of inspired or insufflated vapour has any appreciable influence on
+the body temperature, but there is a fairly general consensus of
+opinion that if the ether vapour is warmed there is less likelihood
+of irritation of the respiratory mucous membrane. It is to be noted,
+moreover, that in intratracheal insufflation the natural apparatus for
+warming the inspired air is put out of action. This warming can be
+effected by the simple device of carrying the tube through a chamber of
+hot water after it emerges from the ether chamber.</p>
+
+<p>4. <span class="smcap">Safety Valve.</span>—Dr Meltzer insists very strongly on the
+necessity of having a safety valve capable of controlling the maximum
+pressure under which the air may enter into the<span class="pagenum" id="Page_102">[102]</span> intratracheal tube. By
+a simple device, any excess of desired pressure will cause the air to
+bubble through mercury and thus never reach the lungs. In this way any
+possibility of accident from undue intrapulmonary pressure is obviated.</p>
+
+  <div class="figcenter" id="i_p102" style="max-width: 549px">
+     <img
+    class="p1"   
+    src="images/i_p102.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 33.</span>—Shipway’s intratracheal apparatus.</p>
+     </div>
+
+<p>5. <span class="smcap">Mercury Manometer</span> to indicate the pressure in the tube in
+m.m. of mercury. It has been experimentally established<a id="FNanchor_7" href="#Footnote_7" class="fnanchor">[7]</a> “that the
+pressure in the trachea and in the bronchi is only a small fraction
+of the pressure in the manometer outside of the body, and that the
+intratracheal pressure grows<span class="pagenum" id="Page_103">[103]</span> considerably less with the decrease of
+the diameter of the intratracheal tube.”</p>
+
+<p>6. <span class="smcap">Intratracheal Catheter.</span>—It is essential to have an
+instrument of adequate rigidity which can be satisfactorily sterilized.
+The ordinary coudé catheters, or the silk web white enamelled
+cylindrical catheters, are suitable. The size should be selected from
+a range of 18 to 25 French. It is preferable to err rather on the side
+of a small than a large tube. An ordinary adult will require a tube of
+about size 22 to 24, a plethoric alcoholic, on the other hand, might
+need a 25.</p>
+
+<p>A tube of too large a calibre interferes with the free return of air
+and spontaneous respiration soon becomes too slow. Expiration is
+prolonged, active, and laboured, and after a few minutes, respiratory
+movements may cease entirely. The only way to meet such a situation is
+to withdraw the tube and insert a smaller one.</p>
+
+<p><span class="smcap">Technique of Administration.</span>—It is advisable in adults to
+administer about three quarters of an hour before the operation, a
+hypodermic injection of morphia (gr. ⅙) and atropine (gr. ¹⁄₁₀₀), or
+of scopolamine (gr. ¹⁄₁₀₀) and morphia (gr. ⅙). The latter combination
+is more efficacious in alcoholic subjects. In children, atropine alone
+should be given.</p>
+
+<p>It is to be remembered that intratracheal insufflation of ether is a
+method of maintaining not of inducing anæsthesia. Induction is carried
+out in the ordinary way. When this has been done, the catheter is
+passed.</p>
+
+<p>The introduction of the catheter does present some difficulty, but
+this is largely overcome as skill and confidence are acquired with
+practice. It may be carried out indirectly, or a view of the glottis
+may be obtained by the aid of such an endoscope as Hill’s, and the
+catheter inserted between the cords. The latter method is probably the
+more satisfactory, but it is well to acquire the<span class="pagenum" id="Page_104">[104]</span> skill to pass the
+catheter indirectly as in a certain small proportion of cases there are
+obstacles to the use of the endoscope.</p>
+
+<p>To facilitate catherization the pharynx and epiglottic region may
+be cocainized with a 5 per cent. solution before induction. Hill’s
+endoscope (Fig. 34) is distally illuminated by a small electric lamp,
+which is connected with a small pocket battery. A useful modification
+of this has been devised by Mr Dott. In it, the catheter is passed
+along a separate compartment, so that the view of the glottis is
+undisturbed. The point of the catheter comes into view at the distal
+extremity of the endoscope and can be guided between the cords into the
+trachea.</p>
+
+  <div class="figcenter" id="i_p104" style="max-width: 307px">
+     <img
+    class="p1"   
+    src="images/i_p104.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 34.</span>—Hill’s Direct Laryngoscope.</p>
+     </div>
+
+<p>It is essential before attempting intubation, that there should be
+thorough relaxation. The lower jaw should be so slack that a gag is not
+required. The head is then placed in the occipito-shoulder position, or
+is allowed to hang over the end of the table. The tongue is controlled
+by forceps, and the endoscope passed slowly along its dorsum until the
+epiglottis comes into view. The point of the endoscope is then passed
+sufficiently far below the tip of the epiglottis to ensure that it will
+not slip; too deep insertion must be avoided. The endoscope being held
+in the left hand, the hyoid bone is lifted up by a tilting movement of
+the hand. The glottis is thus brought into view. The catheter stiffened
+by<span class="pagenum" id="Page_105">[105]</span> means of a probe is then passed through the glottis into the
+trachea and the endoscope withdrawn. The bifurcation of the trachea in
+the adult is at a distance of about 26 cm. from the incisor teeth. The
+catheter should be marked accordingly, and inserted to a point just
+short of this. The probe is then withdrawn, and connection made with
+the air current.</p>
+
+<p>It occasionally happens that unexpected difficulty is met with on
+attempting to pass the catheter by direct vision. The larynx may be so
+fixed that the glottis does not readily come into view; or in the case
+of an intraoral neoplasm the view may be obstructed by the presence of
+blood. In such cases the catheter can be introduced by the indirect
+method. The middle finger of the left hand is passed along the dorsum
+of the tongue until the epiglottis is felt. The index finger is then
+used to guide the point of the catheter to the glottis through which
+it is then passed. No undue force must be used. A stilette should be
+inserted into the catheter which should be moulded almost to a right
+angle at its terminal third. If the stilette is withdrawn when the
+point of the catheter is over the mouth of the glottis, the instrument
+will, as a rule, slip easily into the trachea.</p>
+
+<p>Occasionally the tube passes into the œsophagus. With care and adequate
+relaxation such a mistake should not occur, but the possibility of it
+should be kept in mind. If the operator will abstain from attempting to
+pass the catheter until such time as he has a satisfactory view of the
+glottis, mistakes of this kind will seldom occur. The essentials are a
+good illumination and an adequate relaxation.</p>
+
+<p>Mild glottic spasm may supervene on the passage of the catheter but
+this rapidly passes off. At first the degree of concentration of the
+vapour should be low or irritation will result, evidenced by spasm and
+coughing. The strength of the vapour is gradually increased until the
+necessary concentration is attained. The pressure should vary according
+to the requirements of the<span class="pagenum" id="Page_106">[106]</span> case and should range between 10 mm. to 25
+mm. Hg. The safety valve must be set so as to make any pressure above
+this impossible.</p>
+
+<p>In the majority of cases the course of anæsthesia is smooth and
+uneventful; the colour remains a rosy pink, the pulse is good, and the
+respirations quiet and regular. It is undesirable that the respiratory
+movements should be abolished altogether; their presence indicates that
+neither the central nor the peripheral respiratory mechanism is being
+overdosed with ether.</p>
+
+<p>Theoretically, the constant plus-pressure in the lungs might be
+thought to interfere with the circulation in the large veins, and
+in the pulmonary vessels themselves. It is therefore well to reduce
+the pressure in the catheter to zero every minute by opening the tap
+provided for the purpose for a second or two.</p>
+
+<p>At the conclusion of the operation, before withdrawing the catheter
+it is well to flush out the lungs with air so as to remove any ether
+vapour that is present. In a certain number of cases, notably in
+big alcoholic subjects, difficulty may be experienced in securing
+a sufficiently deep anæsthesia with good relaxation. It is seldom,
+however, that patience and the careful introduction of a stronger
+vapour will not suffice to overcome this. In alcoholic subjects, as
+previously suggested, preliminary medication with scopolamine and
+morphia will help. It really becomes a question, if one may put it
+so, of coaxing the unconscious patient to tolerate an ether vapour of
+adequate strength.</p>
+
+
+<h3><b>Advantages and Special Indications.</b></h3>
+
+<p>The general opinion of anæsthetists appears strongly to favour the view
+that the absence of strain and the perfect æration in intratracheal
+ether insufflation tend to lessen the shock of operation. The
+post-operative history of patients also suggests that there is a
+lessened liability to pulmonary complications as compared<span class="pagenum" id="Page_107">[107]</span> with cases
+in which ether has been administered by other methods. Dr Elsberg<a id="FNanchor_8" href="#Footnote_8" class="fnanchor">[8]</a>
+of New York in this connection writes: “The absence of any pulmonary
+complications has led us to use this method of anæsthesia in all
+patients in whom pulmonary complications were to be feared after an
+anæsthesia or operation. Thus on all asthmatics, in patients with
+chronic bronchitis and emphysema, in patients who require gastric
+resection and the like, we no longer, during two years, have seen the
+much dreaded post-operative pneumonia wherever intratracheal anæsthesia
+was used.”</p>
+
+<p>In addition, there is ample evidence<a id="FNanchor_9" href="#Footnote_9" class="fnanchor">[9]</a> that the introduction of a
+catheter into the trachea and its presence therein does not tend,
+as might have been expected, to set up any irritation at the time
+or predispose to subsequent trouble. Apart from these general
+considerations, which suggest the advantage of a somewhat extended use
+of intratracheal ether insufflation, the method has obvious advantages
+in all operations about the mouth, such as those for excision of the
+upper jaw, those undertaken for the removal of nasopharyngeal growths
+and various plastic operations involving the nasal and buccal cavities.
+In such cases the danger of aspiration of blood, mucus, etc., is
+obviated and the anæsthetist is well out of the surgeon’s way, while at
+the same time an even interrupted delivery of ether vapour is effected.
+In operations for removal of glands in the neck the surgeon has the
+field to himself, and is not hampered nor is his asepsis endangered by
+the proximity of the anæsthetist’s mask.</p>
+
+<p>In such operations as laminectomy and nephrectomy the postural
+difficulties with which the anæsthetist has to contend, and which also
+tend to interfere with free respiration, are eliminated.</p>
+
+<p><span class="pagenum" id="Page_108">[108]</span></p>
+
+<p>The great advantage of the method in intrathoracic operations has
+already been referred to.</p>
+
+<p>The introduction of intratracheal insufflation of ether was rendered
+possible by the pioneer work of Drs Elsberg, Meltzer, and Auer. The
+writer would like to acknowledge his indebtedness to their writings, of
+which he has made free use.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_109">[109]</span></p>
+
+<h2>CHAPTER XI.<br>
+<span class="subhed"><b>CHLOROFORM.</b></span></h2></div>
+
+
+<h3><b>Physical Characteristics.</b></h3>
+
+<p>Chloroform is chemically trichlor-methane, CHCL<sub>3</sub>. It is a
+colourless, transparent fluid, with a specific gravity of 1·491 at
+17°C. Its vapour is even heavier than that of ether, approximately
+four times heavier than air. It is not inflammable, but the action of
+an open fire or naked flame tends to break it up into hydrochloric
+acid and phosgene, both of which are highly irritant gases to all who
+breathe them. The patient suffers, but since all the other occupants of
+the theatre are also affected, warning is given before serious harm has
+been inflicted.</p>
+
+<p>Chemically pure chloroform is a somewhat unstable product, but the
+addition invariably made to it by the producers, of a trace of
+alcohol, prevents any serious risk of decomposition in bulk. It should
+be neutral in reaction and have an agreeable non-irritating odour:
+departure from the normal in either respect indicates the possibility
+of the presence of acids or aldehydes, and the necessity for referring
+a specimen to the laboratory.</p>
+
+<p>Like ether, chloroform may be obtained from pure ethyl alcohol or from
+methylated spirits, and the remarks made in the chapter upon ether
+apply to the case of chloroform also. A third source of supply is
+acetone, from which perfectly good chloroform can be produced.</p>
+
+
+<h3><b>Physiology.</b></h3>
+
+<p>Chloroform is an irritant to the skin and mucous membranes. A drop left
+on the skin and covered over with impermeable<span class="pagenum" id="Page_110">[110]</span> material will produce a
+deep and painful blister. A drop falling into the eye, if not instantly
+washed away, produces a very powerful inflammatory reaction, and many
+eyes have been totally lost from carelessness in this respect. Such
+incidents are of course actionable, and heavy damages may be given.</p>
+
+  <div class="figcenter" id="i_p110" style="max-width: 615px">
+     <img
+    class="p1"   
+    src="images/i_p110.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 35.</span>—Diagrammatic representation of
+various blood pressure curves obtainable with chloroform.</p>
+     <p class="p0 hangingindent smaller">Line ABA′ represents curve desired in normal chloroform administration.</p>
+     <p class="p0 hangingindent smaller">Line ABCB′ represents gradual overdosage.</p>
+     <p class="p0 hangingindent smaller">Line ABCC′ represents recovery by inversion.</p>
+     <p class="p0 hangingindent smaller">DD′ represents syncope from vagal inhibition: in its course, one
+attempt of the heart to “escape” is shown.</p>
+     </div>
+
+<p>The special peculiarities of the action of chloroform upon the nervous
+system have already been emphasised in the account<span class="pagenum" id="Page_111">[111]</span> given of the
+physiology of ether (see page <a href="#Page_75">75</a>). Its action upon the <i>circulatory
+and respiratory systems</i> has been the subject of many researches,
+and of much embittered controversy. The literature is therefore
+very extensive, and the account of it must be severely condensed.
+The following may be taken as a brief resumé of present day opinion
+(<i>see</i> Fig. <a href="#i_p110">35</a>):—</p>
+
+<div class="blockquot">
+
+<p>(1) In every case of chloroform administration, there is a fall
+of blood pressure.</p>
+
+<p>(2) If the drug be presented in weak concentration (less than 2
+per cent. vapour strength), the fall is gradual and even (line
+AB).</p>
+
+<p>(3) If the same strength (say 2 per cent.) of vapour as produced
+the above effect be prolonged unduly, the respiration will cease
+at a time when blood pressure is still well above zero (line
+ABCB′).</p>
+
+<p>(4) The fall of pressure is due to diminished force of cardiac
+action, and at a later stage also to vaso-motor paresis.</p>
+
+<p>(5) The cessation of respiration is due partly to fall of
+blood pressure in the vessels supplying the medullary centre;
+partly to gradual poisoning of the centre itself by the drug.
+That the fall of B.P. in the cerebral vessels is in itself one
+explanation of the cessation of respiration, was proved many
+years ago by Leonard Hill in his inversion experiments. Just
+at the stage when respiration had ceased, the anæsthetic was
+withdrawn, and the animal inverted into the head-down position.
+The B.P. in the carotid at once began to rise, and natural
+respiration was resumed (line A′BCC′).</p>
+</div>
+
+<p>The above conclusions refer to chloroform given in moderate vapour
+strength; other effects are produced if higher percentages are
+administered:—</p>
+
+<p><span class="pagenum" id="Page_112">[112]</span></p><div class="blockquot">
+
+<p>(6) With high concentration of chloroform vapour, the fall
+of blood pressure is rapid, and is apt to become suddenly
+precipitous (line DD′).</p>
+
+<p>(7) The cause of these sudden falls is inhibition of the
+heart by over-activity of the vagus: cutting the vagi always
+terminates the effect unless delayed so long that the animal is
+dead: in an animal fully under atropine, these vagal actions
+cannot be produced.</p>
+
+<p>(8) If the heart is inhibited by vagal action, the respiration
+ceases at once, usually after one deep inspiratory sigh.</p>
+
+<p>(9) An inhibited heart may “escape” from vagal action before the
+animal is dead: frequently, however, the inhibition persists and
+the animal dies.</p>
+
+<p>(10) Struggling and breath-holding in the early stages of
+induction cause sudden falls of blood pressure. Many observers
+believe that these falls also are due to vagal activity,
+others hotly deny this. All are united in believing that to
+<i>press</i> chloroform upon a patient who is struggling and
+holding the breath, is fraught with grave risk of causing sudden
+syncope.</p>
+
+<p>(11) The abnormal irritability of the vagus above referred to is
+a feature mainly of the induction stage, disappearing once full
+anæsthesia is developed.</p>
+
+<p>(12) It is an undoubted clinical fact that there is a risk
+of sudden arrest of heart’s action if the operation is begun
+before the stage of full anæsthesia is reached. A reasonable
+explanation of such accidents is furnished by supposing a reflex
+inhibition acting through the vagal centre already rendered
+hyper-sensitive by partial chloroformisation.</p>
+</div>
+
+
+<h3><b>Views of Goodman Levy.</b></h3>
+
+<p>This worker has demonstrated in animals that the heart is sometimes
+thrown by chloroform into the condition of fibrillation—a delirium
+of the cardiac muscle, from which recovery is rare. It<span class="pagenum" id="Page_113">[113]</span> occurs in
+the early stage, before full anæsthesia has been reached, and is
+predisposed to by the infliction of trauma. The practical outcome of
+this is that the induction stage of chloroform should not be unduly
+prolonged, and that the operation should not be begun until the third
+stage is fully developed.</p>
+
+<p>So far as the author understands the views of Dr Levy, his explanation
+of chloroform syncope need not be taken as introducing any new
+principle into the administration of the drug. Even those who lay most
+emphasis upon the danger of using vapours of too high a percentage
+strength would admit the force of Levy’s contentions. As usual, safety
+lies in steering between two extremes.</p>
+
+<p>During his work on this subject, Levy further demonstrated that
+the introduction into the circulation of <i>adrenalin</i> during
+incomplete chloroform anæsthesia was very liable to induce fatal
+cardiac fibrillation. He thus furnished the explanation of a number
+of deaths which had occurred in the practice of nose and throat
+specialists. Since the publication of Levy’s work, the rule has been
+absolute that if <i>adrenalin</i> is to be used in a case requiring
+chloroform anæsthesia, the adrenalin must <i>precede, not follow</i>
+the anæsthetic.</p>
+
+
+<h3><b>Administration.</b></h3>
+
+<p>Basing upon these views as to the action of chloroform, and upon the
+lessons of practical experience, we may formulate definite rules for
+giving the drug.</p>
+
+
+<h4><b>General Principles for giving Chloroform.</b></h4>
+
+<div class="blockquot">
+
+<p>(1) Give chloroform evenly, not spasmodically.</p>
+
+<p>(2) Increase the vapour strength of chloroform gradually from
+zero until 2 per cent. or at most 2½ per cent. is reached at the
+end of two or three minutes; maintain that strength until full
+anæsthesia is obtained; thereafter, drop down to 1–1·5 per cent.
+This will result in a B.P. curve corresponding to the line ABA′
+in the diagram (Fig. 35).</p>
+
+<p><span class="pagenum" id="Page_114">[114]</span></p>
+
+<p>(3) Be guided chiefly by the patient’s respiration. Chloroform
+kills by stopping the heart, but in the immense preponderance
+of cases, evidence of failure of respiration appears in ample
+time to give warning of approaching circulatory failure. The eye
+reflexes give confirmatory evidence of the depth of anæsthesia,
+but the superlatively important thing is to <i>maintain a free
+airway, and be sure the patient is using it</i>.</p>
+
+<p>(4) If serious struggling and breath-holding occur, withdraw the
+anæsthetic until the patient “resumes normal.”</p>
+</div>
+
+
+<h3><b>Methods of Administration.</b></h3>
+
+<p>The logical application of such general principles would be to use an
+instrument which gives a definite and known percentage of chloroform,
+variable at the wish of the administrator. Many such machines have
+been brought forward, and while none of them have obtained general
+acceptance, a description of the best known instrument will be given,
+as the reader may as a house-surgeon meet with it, and with a surgeon
+who wishes it to be used.</p>
+
+
+<h4><b>Vernon Harcourt’s Inhaler.</b></h4>
+
+<p>In principle, this is a “draw-over” instrument; the patient’s own
+inspirations are the motive power. Passing over the surface of the
+fluid drug, the inspired air picks up from it a known percentage of
+vapour. The other system available for the construction of percentage
+chloroform instruments is the “plenum”; in this the vapour is propelled
+to the patient by a pump.</p>
+
+  <div class="figcenter" id="i_p115" style="max-width: 234px">
+     <img
+    class="p1"   
+    src="images/i_p115.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 36.</span>—Vernon Harcourt’s Percentage
+Chloroform Inhaler.</p>
+     </div>
+
+<p>In appearance, the inhaler resembles the letter T, with a rubber
+face-piece attached to the lower end of the vertical limb (<i>see</i>
+Fig. <a href="#i_p115">36</a>). The T portion itself is made of metal tubing of a definite
+size in cross section. One end of the horizontal limb admits pure air,
+the other, air which has passed over chloroform and picked up from it
+a certain proportion of vapour. The proportion of the total inspired
+volume of air which passes through each of the ends is<span class="pagenum" id="Page_115">[115]</span> regulated by
+a lever seen at the junction of horizontal and vertical limbs, and
+the exact percentage of chloroform being inhaled is indicated by a
+series of numerals marked on the dial over which the lever moves. These
+figures are correct provided:—</p>
+
+<div class="blockquot">
+
+<p>(1) The chloroform receptacle is not shaken (this would greatly
+increase the percentage).</p>
+
+<p>(2) The temperature of the chloroform is not allowed to fall
+below 13° centigrade. To ensure that this cannot take place
+without the knowledge of the administrator, two coloured beads
+are thrown into the chloroform. At the desired temperature of
+the chloroform (13°-15°C) the blue bead sinks to the bottom,
+the red one nearly to the bottom. Below 13°C, the red bead also
+touches bottom, and when this is observed, the chloroform vial
+is warmed up in the palm of<span class="pagenum" id="Page_116">[116]</span> the hand. At the point 15°C, both
+beads float, and the warming must then stop, or an undesirable
+addition to the vapour strength yielded will occur.</p>
+</div>
+
+<p>The face-piece is made of rubber, and must be closely adapted to the
+face; in its side is seen the expiratory valve. Inspiratory valves are
+present at each end of the horizontal limb.</p>
+
+<p>The great advantage of this instrument, to the author’s mind, is for
+teaching or demonstration purposes. If the student <i>sees</i> the
+lever gradually being moved over from ·2 to 2 per cent., then slipped
+back to about 1·5 per cent. after full anæsthesia has been obtained, he
+begins to appreciate what it is he is aiming at when giving chloroform
+by the ordinary open method.</p>
+
+  <div class="figcenter" id="i_p116" style="max-width: 584px">
+     <img
+    class="p1"   
+    src="images/i_p116.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 37.</span>—Schimmelbushch’s mask.</p>
+     </div>
+
+
+<h4><b>Open Method.</b></h4>
+
+<p>The appliances requisite are:—</p>
+
+<div class="blockquot">
+
+<p>(1) A mask. Schimmelbushch’s is the best known (Fig. 37): as
+elsewhere explained, it does not accurately fit the face.</p>
+
+<p>(2) Material to stretch on the mask. The best is two layers of
+domette or one of flannelette: surgical gauze is so<span class="pagenum" id="Page_117">[117]</span> light that
+heavy drops of chloroform are apt to “spark” through it and burn
+the skin of the face: lint rapidly becomes sodden; the drug
+drips away from its edge instead of vapourising properly.</p>
+
+<p>(3) A good drop bottle, of which many varieties are marketted
+(Fig. 38): it is essential that it should be capable of
+producing definite <i>drops</i>: the old method of intermittent
+“douching” of chloroform is to be condemned as violating the
+first general principle for giving the drug.</p>
+</div>
+
+  <div class="figcenter" id="i_p117" style="max-width: 461px">
+     <img
+    class="p1"   
+    src="images/i_p117.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 38.</span>—Chloroform drop bottles.</p>
+     </div>
+
+<p>It is not possible by the open method to be mathematically accurate
+with percentages, but the necessary appliances are simple, easily
+transported, and practically always at hand. If the student learns to
+use it, and while doing so <i>to think in percentages</i>, he will
+achieve as good results as or better than he will with percentage<span class="pagenum" id="Page_118">[118]</span>
+instruments. While he may not have in front of his eyes a dial which
+shows the percentage graphically, observation of the patient will
+inform him whether the percentage being given should be maintained,
+raised, or lowered. The only remaining point for him to realise, then,
+is how in practice such regulations of percentage strength can be
+achieved by the open method. The strength of the vapour will depend
+upon three factors:—</p>
+
+<div class="blockquot">
+
+<p>(1) Nature of the material used on the mask.</p>
+
+<p>(2) Closeness with which the mask is adapted to the face.</p>
+
+<p>(3) Amount of chloroform exhibited on the mask.</p>
+</div>
+
+<p>To ensure uniformity of result, two of these factors should be kept
+constant, and the necessary increase or decrease of vapour strength
+achieved by varying the third. Always use the same type and thickness
+of material on the mask, and allow the mask to lie lightly on the face.
+If the amount of chloroform is then regulated by a strictly “drop”
+method, results of great uniformity may be obtained by the open method.</p>
+
+
+<h4><b>The Junker Inhaler.</b></h4>
+
+<p>This instrument was originally introduced as an attempt to achieve a
+percentage method. Air is pumped through a certain depth of chloroform
+contained in a bottle, and the vapour brought to the patient in the
+face-piece shown in Fig. 39. The calculations by which it was sought
+to establish this as a reliable dosimetric or percentage method are of
+no great value. From that standpoint the instrument has not achieved
+success. It delivers to the patient a <i>small quantity of high
+percentage vapour</i> which is diluted by a much larger quantity of
+air inspired by the patient from the general atmosphere, and the final
+percentage inhaled by the patient is therefore no more accurately known
+to the administrator than in the open method.</p>
+
+<p>The instrument is, however, of considerable value for tongue and jaw
+cases, where anæsthesia has to be maintained for some<span class="pagenum" id="Page_119">[119]</span> considerable
+time after the mask with which anæsthesia has been induced has had to
+be removed, to give access to the surgeon.</p>
+
+  <div class="figcenter" id="i_p119" style="max-width: 522px">
+     <img
+    class="p1"   
+    src="images/i_p119.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 39.</span>—Junker’s Chloroform Inhaler showing hand
+bellows, bottle and mask. Alternatively to the latter, the nasal
+tube shown above, may be used.</p>
+     </div>
+
+<p>The Figure 39 shows the instrument as usually marketed. It consists
+of:—</p>
+
+<div class="blockquot">
+
+<p>(1) A hand-bellows.</p>
+
+<p>(2) Chloroform bottle. A mark cut on this shows the level to
+which it is to be filled: if more than the proper quantity be
+poured in, droplets of fluid chloroform are apt to be blown
+along the exit tube, with dangerous results.</p>
+</div>
+
+<p>For convenience and neatness, it is usual to make the exit surround
+the inlet tube. The entering air bubbles through the chloroform,
+and a stream of air and chloroform vapour passes out<span class="pagenum" id="Page_120">[120]</span> from the exit
+tube.<a id="FNanchor_10" href="#Footnote_10" class="fnanchor">[10]</a> It is unnecessary to give a detailed account of the use of
+the instrument, but the student must remember the following points:—</p>
+
+<div class="blockquot">
+
+<p>(1) The amount of chloroform vapourised will depend on the
+vigour of the pumping, the depth of fluid, and the temperature
+of the chloroform. In order to achieve uniform results, it
+is therefore necessary to keep up a steady but not excessive
+pumping, to warm up the bottle occasionally by holding it in the
+palm of a disengaged hand, and to watch that the level of the
+chloroform does not fall too low.</p>
+
+<p>(2) The pumping should be timed to synchronise with inspiration:
+a puff of vapour delivered during an expiration will be wasted.</p>
+</div>
+
+
+<h3><b>Advantages and Disadvantages of Chloroform.</b></h3>
+
+<p>The light portable appliances which are alone necessary for chloroform
+anæsthesia, the comparative cheapness of the method, and the
+<i>apparent</i> ease with which its administration may be conducted,
+are all great temptations to its use. Those who feel the temptation
+strong upon them are advised to remember the following quotation from
+the writings of Professor Leonard Hill:—</p>
+
+<p>“Chloroform is a drug used by the young anæsthetist with the utmost
+hardihood, and until he has had the misfortune in his practice to meet
+with a death caused by it, he derides the danger of the drug, and
+asserts that its safety merely depends on the care and skill of the
+administrator. After losing his patient, he falls to descanting on the
+unavoidable dangers of the drug, dangers which he is now the first to
+maintain cannot be met by any degree of skill in administration.”</p>
+
+<p><span class="pagenum" id="Page_121">[121]</span></p>
+
+<p>The most distressing and probably the most common chloroform fatalities
+are exemplified in administration given for the most trifling
+conditions, such as opening abscesses or extracting teeth.</p>
+
+<p>In general, we use chloroform if for any reason ether is not
+applicable. For examples of cases of this description, the reader is
+referred to the chapter upon the choice of anæsthetics.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_122">[122]</span></p>
+
+<h2>CHAPTER XII.<br>
+<span class="subhed"><b>ETHYL CHLORIDE.</b></span></h2></div>
+
+<p>Chemically this drug has the formula C<sub>2</sub>H<sub>5</sub>Cl. It is a colourless
+fluid so volatile that it boils at ordinary room temperature. Its
+vapour is highly explosive, and the fluid itself very inflammable. The
+drug is supplied by the makers in small tubes with a metal end which
+can be opened by pressing a little lever (<i>see</i> Fig. <a href="#i_p122">40</a>), varying
+in type with the brands made by various makers. Two brands are sold
+by each firm; one is chemically pure, intended for use as a general
+anæsthetic; the other is not so pure, and is only sold for local
+anæsthesia. Such a product is not suitable for inhalation.</p>
+
+  <div class="figcenter" id="i_p122" style="max-width: 150px">
+     <img
+    class="p1"   
+    src="images/i_p122.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 40.</span>—Tube of Ethyl Chloride.</p>
+     </div>
+
+
+<h3><b>Physiology.</b></h3>
+
+<p>The special points in the physiology of ethyl chloride may be briefly
+summarised as follows:—</p>
+
+<div class="blockquot">
+
+<p>1. After a trifling preliminary rise, the effect of the drug
+is to lower the blood pressure appreciably. In the human adult
+subject, this fall becomes appreciable when more than 3 c.c.
+have been given; if the dose exceed 5 c.c. a fall of 30 to 40
+mm. of Hg. is probable,—occurring as it does within a period of
+perhaps twenty or thirty seconds, such a fall cannot be regarded
+as safe.</p>
+
+<p><span class="pagenum" id="Page_123">[123]</span></p>
+
+<p>2. The cause of this fall is diminished cardiac output from
+weakening of heart muscle. The vagus though not paralysed, does
+not appear to be unduly irritable, as it does with chloroform.</p>
+
+<p>3. The respiratory centre is at first perceptibly stimulated,
+and respiration is therefore deeper and quicker than normal. The
+stimulant effect rapidly passes away and gives place to a stage
+of depression.</p>
+</div>
+
+<p>In the majority of cases, death appears to take place from paralysis
+of the respiratory centre, the heart still showing a little power of
+contraction after respiration has ceased. There is therefore a fair
+prospect of recovery if artificial respiration be resorted to promptly.</p>
+
+
+<h3><b>Methods of Administration.</b></h3>
+
+
+<h4 class="smcap">Open Method.</h4>
+
+<p>The extreme volatility of the drug has discouraged most anæsthetists
+from giving it upon an open mask. Hornabrook, of Melbourne, advocates
+this system, however. His mask fits the face accurately, and his whole
+method is strictly perhalational. He uses some 4–6 c.c. of the drug
+for a child, 6–8 c.c. for an adult, and achieves his anæsthesia in a
+minute to a minute and a half. He also advocates open ethyl chloride
+as a preliminary to open ether. For some twelve months, the author
+adopted the method. At the end of that time he came to the conclusion
+that while it greatly facilitated the induction stage of open ether,
+it appeared to increase the after sickness. He therefore abandoned it,
+though rather reluctantly.</p>
+
+
+<h4 class="smcap">Closed Method.</h4>
+
+<p>This is the usual means employed. A variety of inhalers have been
+produced on the market, one of which is shown in Fig. 41. Essentially
+all consist of:—</p>
+
+<div class="blockquot">
+
+<p>(<i>a</i>) A face-piece which must fit the face with reasonable
+accuracy.</p>
+
+<p>(<i>b</i>) A one-gallon rubber bag attached to the mask by a
+T-piece.</p>
+
+<p><span class="pagenum" id="Page_124">[124]</span></p>
+
+<p>(<i>c</i>) A glass vial, with numerals from 1 to 5 marked on the
+outside to facilitate the measurement of the drug in c.c. Into
+this the drug is squirted from the makers’ tube. The vial is
+attached to the T-piece (or alternatively the bottom of the bag)
+by a rubber tube.</p>
+</div>
+
+  <div class="figcenter" id="i_p124" style="max-width: 205px">
+     <img
+    class="p1"   
+    src="images/i_p124.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 41.</span>—Ethyl Chloride Inhaler.</p>
+     </div>
+
+
+<h3><b>Administration.</b></h3>
+
+<p>To use such an inhaler, the glass vial is first detached from the
+rubber tube, and the chosen dose of drug squirted into it. A<span class="pagenum" id="Page_125">[125]</span> child
+of five or six will require 3 c.c., an adult up to 5 c.c.; this dose
+should never be exceeded. The vial is then rapidly reconnected with
+the inhaler. The face-piece is adapted to the face, care being first
+taken to place between the teeth a mouth prop or a gag. This enables
+one to get immediate access to the mouth when the inhaler is removed.
+The patient is then told to breathe deeply once or twice. During the
+inspiration the mask is lifted slightly, and the ensuing expiration is
+then caught in the bag by pressing down the mask on to the face. To
+volatilise the drug there are two alternative methods. In the one, part
+or the whole of the dose is tipped into the rubber bag by elevating the
+vial. A far better is the “Vapour” method, almost universally used in
+Edinburgh owing to the advocacy of Dr Logan Turner. A tumbler is filled
+with hot water, and the bottom of the glass vial is allowed first to
+touch, and after a few seconds to be immersed in it. Some thirty to
+forty seconds suffice to vapourise the whole of the dose.</p>
+
+<p>Ethyl chloride given by itself should always be administered to a
+patient in the recumbent position. A dose sufficient to produce
+anæsthesia without the aid of nitrous oxide or ether will not be safe
+in the erect posture. The case is quite different where a small dose
+only is given, to assist the action of nitrous oxide, or facilitate the
+induction stage of ether.</p>
+
+
+<h3><b>Signs of Anæsthesia.</b></h3>
+
+<p>Ethyl chloride is very rapid in its action, some sixty seconds
+availing to produce quite a deep anæsthesia. <i>Respiration</i> is
+at first deepened and quickened: as full anæsthesia is attained it
+remains rather deeper than normal, and is accompanied usually by light
+snoring. The colour should remain perfectly good: the pupils show
+marked dilatation, the corneal reflex is abolished, and good muscular
+relaxation is attained.</p>
+
+<p>With no anæsthetic is it so essential as with this, to become<span class="pagenum" id="Page_126">[126]</span>
+acquainted with the type of respiration normally to be expected, and to
+watch for any departure therefrom with cat-like vigilance. The other
+danger signal is the pupil. It should be dilated, but a rim of iris
+should still be perceptible.</p>
+
+<p>Once anæsthesia is established, the inhaler should be removed, and the
+surgeon may begin his work. He will have for its completion some 80–90
+seconds against the 40–50 available after nitrous oxide. With ethyl
+chloride there is a somewhat prolonged “analgesic” stage. The patient
+is partly conscious and may even be phonating, but seems unconscious of
+the infliction of pain unless very severe measures are being used.</p>
+
+
+<h3><b>The Scope of Ethyl Chloride.</b></h3>
+
+<p>When first introduced, it was expected by enthusiasts that the
+lightness and portability of the drug itself and of the necessary
+inhaler, would enable ethyl chloride to oust nitrous oxide from its
+recognised place in surgery and dentistry. These high expectations
+have for several reasons not been fulfilled. In the first place, this
+drug is essentially a “single dose” anæsthetic. Most authorities view
+coldly all attempts to prolong anæsthesia by repeated or continued
+administration. Secondly, ethyl chloride has a mortality rate very much
+greater than nitrous oxide if doses sufficient in themselves to produce
+anæsthesia are habitually used (<i>vide supra</i>). The introduction
+of the “vapour” method has done much to mitigate the risks, but even
+then, this anæsthetic cannot approach the high level of safety rightly
+credited to N<sub>2</sub>O. Moreover, it leads to after vomiting much more
+commonly than its rival.</p>
+
+<p>In many schools these considerations have been held so powerful that
+ethyl chloride has been entirely abandoned. It is, however, a very
+valuable drug for the following purposes:—</p>
+
+<div class="blockquot">
+
+<p>(1) The removal of tonsils and adenoids. For this operation,
+the speed with which the patient (usually a child) loses
+consciousness, the pleasant type of anæsthesia and<span class="pagenum" id="Page_127">[127]</span> absence of
+all serious asphyxial phenomena, and the rapid re-appearance
+of the cough reflex when once the inhaler is removed, are all
+strong recommendations.</p>
+
+<p>(2) As an adjuvant to gas, or gas oxygen (<i>see</i> Chapter
+<span class="allsmcap">XIII.</span>).</p>
+
+<p>(3) As a help to the speedy and comfortable induction of “closed
+ether” (<i>see</i> Chapter <span class="allsmcap">XV.</span>).</p>
+</div>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_128">[128]</span></p>
+
+<h2>CHAPTER XIII.<br>
+<span class="subhed"><b>MIXTURES OF NITROUS OXIDE AND ETHYL CHLORIDE.</b></span></h2></div>
+
+<p>Dr Guy, Dean of the Edinburgh Dental School, introduced some years
+ago a method of giving ethyl chloride in mixture with nitrous oxide.
+Guy’s objective was to utilise the many excellent features of the drug
+without incurring the risks which are apparently inherent in it when
+a dose sufficient in itself to induce full narcosis is used. Given in
+mixture with gas, a much smaller dose suffices.</p>
+
+  <div class="figcenter" id="i_p128" style="max-width: 229px">
+     <img
+    class="p1"   
+    src="images/i_p128.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 42.</span>—Guy’s inhaler for N<sub>2</sub>O and Ethyl
+Chloride.</p>
+     </div>
+
+<p>His original apparatus is shown in Fig. 42, the details are shown in
+Fig. 43. The horizontal limb of a 3-way gas tap is prolonged half an
+inch. In each side of the prolongation is a hole. The bag mount has
+in its side also one hole, which is connected by a universal ball and
+socket joint, with the rubber tube to which the ethyl chloride vial is
+attached. An indicator on the outside of the bag mount and a mark upon
+the outside of the horizontal limb of the 3-way tap, serve by their
+apposition or the reverse to show whether the ethyl chloride vial is in
+direct continuity with the interior<span class="pagenum" id="Page_129">[129]</span> of the inhaler. For purposes of
+description, Dr Guy calls these two positions, “in register” and “out
+of register.”</p>
+
+<p>To use the instrument, the ethyl chloride vial is removed, and the side
+pipe attached to a cylinder of nitrous oxide. The indicator of the
+3-way tap is put at “air” and the bag mount “in register.” The bag is
+then filled with gas by opening the head of the cylinder. The bag mount
+is now put “out of register,” and the side tube disconnected with the
+cylinder. The bag, being closed, remains full of gas.</p>
+
+  <div class="figcenter" id="i_p129" style="max-width: 700px">
+     <img
+    class="p1"   
+    src="images/i_p129.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 43.</span>—Guy’s Instrument for Gas and Ethyl
+Chloride. Details of valve piece and bag mount, showing side tube for
+attachment of Ethyl Chloride vial.</p>
+     </div>
+
+<p>A suitable dose of ethyl chloride is now squirted into the vial. To
+an adult, Dr Guy gives 3 c.c.: on no account is this dose exceeded:
+children take 1½–2 c.c.—even adults often get less than 3 c.c. The
+vial is now attached to the side tube again, and the inhaler is ready
+for use.</p>
+
+<p>After application of the mask to the face, the 3-way tap is at once
+pushed over to “no valve” and the patient rebreathes the gas in and out
+of the bag for some six or eight respirations. The<span class="pagenum" id="Page_130">[130]</span> bag mount is now
+turned round “into register,” and the ethyl chloride tipped into the
+bag. In a further twenty-five seconds the mask may be removed and the
+operation begun.</p>
+
+<p>The available period of anæsthesia is eighty to ninety seconds,
+counting from the instant of the removal of the inhaler.</p>
+
+<p>This method was in use for some years at the Dental Hospital of
+Edinburgh; no instance of danger to life was ever seen. With so small a
+dose of ethyl chloride, the erect position necessary for the purposes
+of dentistry is perfectly safe.</p>
+
+  <div class="figcenter" id="i_p130" style="max-width: 447px">
+     <img
+    class="p1"   
+    src="images/i_p130.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 44.</span>—Diagram of the method introduced by
+Dr Guy and the author for giving Nitrous Oxide and Oxygen, with or
+without Ethyl Chloride.</p>
+     </div>
+
+<p>This inhaler, of course, will serve admirably for giving ethyl chloride
+without gas, and the author habitually uses it for giving the drug by
+the “vapour” method.</p>
+
+<p>In 1911, Dr Guy and the present author modified the method so as to
+permit the use of oxygen with the nitrous oxide. The inhaler which
+they then introduced serves also for nitrous oxide and oxygen, unaided
+by ethyl chloride, and the author has by its means given gas-oxygen
+to a considerable number of major surgical<span class="pagenum" id="Page_131">[131]</span> cases. He now, however,
+limits its use to short anæsthesias, and uses a sight-feed or a Clarke
+apparatus for long cases.</p>
+
+  <div class="figcenter" id="i_p131" style="max-width: 236px">
+     <img
+    class="p1"   
+    src="images/i_p131.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 45.</span>—The Guy-Ross Inhaler for Nitrous
+Oxide and Oxygen, with or without Ethyl Chloride.</p>
+     </div>
+
+<p><span class="pagenum" id="Page_132">[132]</span></p>
+
+<p>In Fig. 44 will be found a diagram showing the method by which the
+oxygen is introduced. The 1-gallon oxygen bag is either attached
+directly to a cylinder, or suspended on an upright as shown in Fig.
+45. In either case, the bag is, before the administration, moderately
+filled with oxygen: one bagful will suffice for a short anæsthesia, and
+the supply of the oxygen from the cylinder is therefore turned off at
+once. For long cases, of course, a small trickle of oxygen into the bag
+is required to replace the gas used.</p>
+
+<p>In the outlet pipe from the oxygen bag is placed a ball syringe of 2
+ounces capacity. A valve in the pipe obliges the flow of oxygen to take
+place in one direction only when the bulb is squeezed, viz. from oxygen
+bag to inhaler.</p>
+
+<p>The remainder of the apparatus is identical with Guy’s original
+inhaler, except that the bag is of 2-gallon capacity, and is perforated
+at its base by a <b>Y</b>-tube, one limb of the fork bringing in the
+nitrous oxide, the other the oxygen.</p>
+
+
+<h3><b>Method of Use.</b></h3>
+
+<p>A few breaths of pure nitrous oxide gas are usually allowed “on the
+valve.” Rebreathing is then instituted, and the addition of oxygen
+begun. The amount required to each type of patient can only be learnt
+with experience, but the average is one full compression of the bulb
+every ten seconds. If anæsthesia is not complete at the end of one
+minute, put the indicator to “valves” again, and allow the patient
+nearly to empty the bag. Then push back the indicator to “no valves,”
+and refill the bag with nitrous oxide by opening the cylinder with the
+foot key. Some four to six compressions of the bulb are made while the
+nitrous oxide is running in. The time will now have come to add the
+dose of ethyl chloride if it be judged necessary at all. This will have
+been placed in the vial before the administration is begun.<span class="pagenum" id="Page_133">[133]</span> After
+emptying the ethyl chloride into the bag of the inhaler, anæsthesia
+should be complete in twenty-five seconds.</p>
+
+<p>The same small doses of ethyl chloride are used as is the case with
+Guy’s original method.</p>
+
+<p>After a little practice under supervision, students at the Dental
+Hospital learn to use this method safely and well. No example of risk
+to life has arisen after eight years’ daily experience.<a id="FNanchor_11" href="#Footnote_11" class="fnanchor">[11]</a></p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_134">[134]</span></p>
+
+<h2>CHAPTER XIV.<br>
+<span class="subhed"><b>MIXTURE OF CHLOROFORM AND ETHER.</b></span></h2></div>
+
+<p>The mere addition of ether does not remove all the undesirable features
+of chloroform anæsthesia. A heart poisoned by excess of CHCl<sub>3</sub> does
+not respond to ether stimulation. Nevertheless, CE mixtures of varying
+proportions have great value. The less lethal drug takes on part of the
+work of the more dangerous one; it also keeps the respiratory centre
+active. Viewing mixtures as dilute chloroform, it is also obvious that
+there will be with them a greater margin of error in dosage, than with
+the pure drug.</p>
+
+<p>Some chemical change takes place when the two drugs are mixed, for heat
+is evolved; of the nature of this change we are ignorant.</p>
+
+<p>The first mixture introduced was known as ACE, and consisted of one
+part absolute alcohol, two parts chloroform, and three parts ether.
+Alcohol evaporates very slowly and if it be introduced at all it should
+be in much smaller proportion. Schäfer’s mixture is one part alcohol to
+nine parts chloroform. Neither of these mixtures is now much used. The
+most useful combination is two parts chloroform and three parts ether,
+and is known as C<sub>2</sub>E<sub>3</sub>. In special cases, one part of chloroform to
+two parts ether may be better.</p>
+
+
+<h3><b>Methods.</b></h3>
+
+<p><i>Cones</i> of varying type were at first extensively used for
+mixtures. The best known is Rendle’s (Fig. 46). It is made of
+celluloid, and is perforated at the top by a series of small holes
+through which the anæsthetic is introduced. A sponge is packed<span class="pagenum" id="Page_135">[135]</span> into
+the upper part of the cone, and a flannelette cover completes the
+appliance. The objection to the use of this and kindred cones is that
+since chloroform evaporates more slowly than ether, the more dangerous
+drug is apt to collect in the sponge, completely altering the strength
+of the vapour after a time. This fault is remedied to a large extent by
+the open drop method now used.</p>
+
+  <div class="figcenter" id="i_p135" style="max-width: 496px">
+     <img
+    class="p1"   
+    src="images/i_p135.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 46.</span>—Rendle’s Cone.</p>
+     </div>
+
+
+<h4><b>The Open (Drop) Method.</b></h4>
+
+<p>For this the mask and ether dropper of Bellamy Gardner are admirably
+suited (Fig. 27). A material less close than the gauze advocated for
+open-ether is required. One layer of flannelette does very well, or
+the cheap cotton towels which used to be known in Edinburgh as “penny
+towels” in the pre-war period. The mask should fit the face with
+reasonable accuracy: there is no reason why a gauze ring should not be
+used to ensure this if the administrator is careful to adhere strictly
+to a “drop” method.</p>
+
+<p>The bottle into which the dropper is inserted should be of different
+<i>colour</i> to those in which pure ether is habitually carried. This
+is a greater safeguard against a dangerous forgetfulness than a mere
+label.</p>
+
+<p><span class="pagenum" id="Page_136">[136]</span></p>
+
+<p>As already said, the anæsthetic must be given by a strict “drop”
+method. “Douching” at frequent intervals gives results far inferior.</p>
+
+<p><span class="smcap">The Type of Anæsthesia</span> is a compromise between that of
+chloroform and open-ether. Respirations and colour are better than with
+pure chloroform, not so good as with open-ether. The size of the pupil
+is also intermediate.</p>
+
+<p><span class="smcap">Scope.</span>—As elsewhere explained there are many patients to whom
+open-ether cannot well be given; the greatest number of these can take
+a mixture perfectly and C.E. should certainly be chosen in preference
+to pure chloroform when possible. For refractory cases, it serves
+admirably as the inducing agent before the use of open-ether.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_137">[137]</span></p>
+
+<h2>CHAPTER XV.<br>
+<span class="subhed"><b>SEQUENCES.</b></span></h2></div>
+
+<p>By a sequence we mean a method in which anæsthesia is partially or
+wholly induced by one anæsthetic or one method, and maintained by
+another. The methods mentioned in Chapter <span class="allsmcap">XIII.</span> as devised
+by Dr Guy for dental purposes are examples which have already been
+sufficiently described.</p>
+
+
+<h3><b>C.E. Mixture—Ether Sequence.</b></h3>
+
+<p>Of the method of inducing anæsthesia by <i>C.E.</i>, and turning later
+to <i>open-ether</i>, we have also already spoken. One thing remains to
+be said in this connection. Learn to judge the appearance of the type
+of patient who will require this alternative to open-ether induction,
+and use the sequence to such patients from the beginning. Don’t start
+off with open-ether, and find out in a few minutes that the patient
+is too obstreperous. A change from mixture to ether is harmless, the
+reverse process needs much care.</p>
+
+<p>The sequence of <i>C.E. to closed ether</i> was advocated by Hewitt as
+a means of dealing with very alcoholic men, and for this purpose has
+great merits. The mixture is given until the stage of struggling is
+just about to commence, a point which experience enables one to fix
+with considerable accuracy. The remainder of the induction is conducted
+by a closed-ether inhaler, either the Hewitt wide-bore or preferably
+the Ormsby. The ether indicator which stands at about one when the
+inhaler is first applied, may be advanced very rapidly full ether
+strength being attained within a minute or two.<span class="pagenum" id="Page_138">[138]</span> As soon as rebreathing
+is begun with either of these instruments, it is very striking to watch
+the rapid and apparently safe subsidence into anæsthesia of the most
+troublesome patient. The struggling is cut short and greatly minimised
+in violence, and a stage which under CHCl<sub>3</sub> might have presented some
+considerable risk of secondary syncope, is thus eliminated.</p>
+
+
+<h3><b>Nitrous Oxide and Ether Sequences.</b></h3>
+
+<p>This is a method greatly superior to the induction by closed-ether
+described on p. 79. Instead of the 1-gallon bag of the Clover or Hewitt
+instrument, the valve piece and 2-gallon bag of a gas apparatus are
+attached to the head of the ether inhaler (Fig. 23, on page 77).</p>
+
+<p>Once the gas bag is inflated from the cylinder, the supply of gas may
+be cut off. A few breaths of gas “upon the valves” are given, until the
+bag is half empty; the valve tap is then pushed over to “no valves” and
+rebreathing begun. Ether may be turned on a few seconds later, and the
+strength of the vapour may be increased more rapidly. Three-quarter
+strength of ether may be attained as a rule in ninety seconds. There is
+very little likelihood of struggling in this method.</p>
+
+
+<h3><b>Ethyl Chloride and Ether.</b></h3>
+
+<p>This is a valuable method for short operations, being easily portable,
+speedy and safe in action, and fairly agreeable to the patient. Some
+anæsthetists use this induction method as a prelude to open-ether.</p>
+
+<p>The Clover (or Hewitt wide-bore) instrument is interposed between the
+face-piece and the T. of the ethyl chloride inhaler, as shown in Fig.
+47. A small dose of ethyl chloride only is requisite; for an adult, 3
+c.c. is enough. This is vapourised over hot water in the usual way; a
+very light anæsthesia is induced in some<span class="pagenum" id="Page_139">[139]</span> sixty seconds, and the ether
+can then be turned on at a much quicker rate than if the induction be
+conducted by that drug alone.</p>
+
+  <div class="figcenter" id="i_p139" style="max-width: 548px">
+     <img
+    class="p1"   
+    src="images/i_p139.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 47.</span>—Clover’s Inhaler adapted for the
+Ethyl Chloride-Ether sequence.</p>
+     </div>
+
+
+<h3><b>Scope.</b></h3>
+
+<p>The gas-ether and ethyl chloride-ether sequences are most useful
+methods. They are quick, safe, and powerful.</p>
+
+<p>Either may be used as “single dose” anæsthetic, the ether being pushed
+quickly up to “full” and the inhaler then withdrawn. If, however, no
+access to the mouth is required by the surgeon, ether anæsthesia may,
+by occasional breaths of fresh air be prolonged for as long as desired.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_140">[140]</span></p>
+
+<h2>CHAPTER XVI.<br>
+<span class="subhed"><b>THE ACCIDENTS OF ANÆSTHESIA.</b></span></h2></div>
+
+<p>The minor difficulties of anæsthesia have already been dealt with,
+and if the instructions already given, particularly in Chapter
+<span class="allsmcap">III.</span>, are faithfully carried out, incidents of real danger
+will rarely occur. The soundest knowledge and the most conscientious
+care will, however, never entirely rid anæsthesia of an element of
+danger to life. The conditions now to be considered are:—</p>
+
+<div class="blockquot">
+
+<p>(<i>A</i>) Vomiting.</p>
+
+<p>(<i>B</i>) Failure of respiration.</p>
+
+<p>(<i>C</i>) Failure of circulation.</p>
+</div>
+
+
+<h3><b>(A) Vomiting.</b></h3>
+
+<p>This always exposes an unconscious patient to the danger of inhaling
+solid or fluid material into the larynx, with resulting asphyxia. If
+the patient be tided through that immediate difficulty, he is liable to
+develop an inhalational pneumonia subsequently.</p>
+
+<p>A healthy patient properly prepared should not vomit during the
+induction stage, nor during the progress of the operation. If he
+does, it means that the induction has been too slow, or that the
+administration has been intermittent, and the patient has been
+permitted to come to too light a level of anæsthesia during the
+operation.</p>
+
+<p>During emergency operations where the patient’s stomach may be full of
+food, the case is different. Such patients commonly vomit early in the
+induction stage, and no skill can avert the incident.</p>
+
+<p>A patient suffering from intestinal obstruction, or from<span class="pagenum" id="Page_141">[141]</span> generalised
+peritonitis has his stomach and intestines full of highly infective
+fluid. Reverse peristaltic may set in merely as the result of the
+inhalation, or later from handling the contents of the abdomen, and
+the feculent fluid gushes up the œsophagus with little or no warning.
+Since vomiting in these cases may occur even in deep anæsthesia, when
+the cough reflex which is the normal sentry to the entrance of the
+larynx, is abolished, the dangers of insufflation are very real indeed.
+Personally, the author prefers to wash out the stomach before beginning
+to induce anæsthesia in these cases, but some surgeons believe that the
+shock of this procedure outweighs the advantages.</p>
+
+
+<h4 class="smcap">Symptoms and Treatment of Vomiting.</h4>
+
+<p>In ordinary cases, vomiting is usually heralded by a definite train of
+symptoms. Respiration becomes shallow, the colour a little pale and the
+pulse rather small. The pupil dilates, but remains active to light,
+indicating that the alteration of respiration and circulation is not
+due to overdose.</p>
+
+<p>At the first appearance of such symptoms, a brisk rub of the lips and
+thereafter an increase of the vapour strength of the anæsthetic will
+often avert the impending vomiting by deepening the anæsthesia, but if
+the possibility of this complication has occurred to the anæsthetist
+too late for its prevention, the head must be turned well to one side,
+and the other shoulder slightly elevated by a pillow, so that vomited
+material will fall out of the mouth at once. When the actual act of
+vomiting is over, no time must be lost in mopping out the mouth and
+pressing on with the production of a deeper anæsthesia.</p>
+
+
+<h3><b>(B) Respiratory Dangers.</b></h3>
+
+<p>These divide themselves into two groups:—</p>
+
+<div class="blockquot">
+
+<p>(1) <span class="smcap">Mechanical.</span>—The respiratory movements continue,
+but the ingress and egress of air is blocked.</p>
+</div>
+
+<p><span class="pagenum" id="Page_142">[142]</span></p>
+
+<p><i>The symptoms and preventative treatment</i> have been referred to at
+some length in Chapter <span class="allsmcap">III.</span>, and no further account of these
+is therefore necessary. <i>The treatment of a complete blockage</i> of
+the air passages which resist the measure there described, alone remain
+to be mentioned. Of these, the only two effective are <i>artificial
+respiration and tracheotomy</i> (or laryngotomy if preferred by the
+surgeon). Forcible artificial respiration by the Sylvester method,
+with the mouth gagged open and the tongue held forward by the tongue
+forceps, is frequently successful in getting over even a complete
+block, but the last resort of opening the air passage by the knife must
+not be delayed until too late. In deciding such a point, considerable
+judgment is of course called for.</p>
+
+
+<h4>(2) <span class="smcap">Non-mechanical.</span>—Respiratory arrest.</h4>
+
+<p>This is usually seen in conjunction with a serious failure of the
+circulation caused by over-dosage. Exceptionally, some act of the
+surgeon sets up a reflex inhibition of the respiratory centre; the
+circulation is at the same time depressed, but to a varying degree.
+The cardinal <i>symptom</i> is arrest of all respiratory effort. The
+<i>treatment</i> is best dealt with under the heading of circulatory
+failure.</p>
+
+
+<h3><b>(C) Circulatory Failure, or Syncope.</b></h3>
+
+<p>By the term syncope, we mean a more or less sudden failure of the
+cardiac pump, as opposed to the form of circulatory failure seen in
+surgical shock, where the condition is chiefly, though not wholly, one
+of vaso-motor paralysis (<i>see</i> Chapter <span class="allsmcap">II.</span>).</p>
+
+<p>Syncope occurs under varying conditions which may for descriptive
+purposes be divided into four classes. It is not, however, always
+possible to decide with certainty into which class an individual case
+should be placed.</p>
+
+<p>The <i>symptoms</i> common to all classes of syncope are:—</p>
+
+<div class="blockquot">
+
+<p>(1) Pallor, and loss of all tone in the muscles, noticeably
+those of expression. The pulse is weak or imperceptible.</p>
+
+<p><span class="pagenum" id="Page_143">[143]</span></p>
+
+<p>(2) Cessation of respiration.</p>
+
+<p>(3) Dilatation of the pupil, which ceases to react to light.</p>
+</div>
+
+<p>The four classes above mentioned are as follows:—</p>
+
+
+<h4>A. <span class="smcap">Primary Syncope.</span></h4>
+
+<p>This is peculiar to chloroform. With no other anæsthetic is it seen, at
+any rate in the healthy subject. It arises during the induction period,
+and is not necessarily preceded by any respiratory difficulty. There is
+one big inspiratory gasp, sudden and extreme pallor, and the pupil goes
+out to the rim in a few seconds. The only reasonable explanation of
+such an incident is the occurrence of vagal inhibition (<i>see</i> page
+<a href="#Page_112">112</a>). Its prevention therefore is a matter of the avoidance of a high
+percentage of chloroform.</p>
+
+
+<h4>B. <span class="smcap">Secondary Syncope.</span></h4>
+
+<p>This term is applied to a collapse arising as a secondary result of
+embarrassed respiration. Though not peculiar to chloroform, it is
+far more common with that drug than with any other (ethyl chloride
+excepted). The most common time for the accident is towards the end
+of the induction period. The patient has probably been struggling,
+has clenched the jaws, and developed “mechanical” asphyxia. Violent
+inspiratory efforts are still being made, and considerable cyanosis
+develops. Either at the very moment when the respiratory difficulty
+is overcome, or while it still persists, the colour suddenly alters
+from blue to white, and the other symptoms of syncope rapidly appear.
+The exact period required to transform a blue struggling patient with
+heaving chest, into one with pallid face, and motionless chest and
+limbs, varies greatly, for reasons furnished below.</p>
+
+<p>The most reasonable explanation offered of such an accident is that
+given by Leonard Hill. The attempts to inspire through an air<span class="pagenum" id="Page_144">[144]</span> way
+mechanically blocked cause an immense strain upon the heart muscle. The
+flow of blood in the lung capillary is hindered, and the right side of
+the heart becomes over distended with blood. Its musculature is further
+damaged by the fact that the blood in the coronary vessels is deficient
+in oxygen, and that a considerable dose of anæsthetic has already been
+absorbed. There is the further fact, not mentioned by Hill, that during
+the whole period of asphyxia the peripheral resistance is rising from
+vaso-constriction. Under circumstances such as these, it is obvious
+that <i>any</i> heart must ultimately succumb, <i>no matter what
+anæsthetic is in use</i>. It is also obvious that with chloroform and
+ethyl chloride, which are themselves heart poisons, secondary syncope
+will happen much more readily than with ether or nitrous oxide, which
+are not; and that a heart with diseased musculature will fail quicker
+than a healthy organ.</p>
+
+<p>Secondary syncope is almost certainly the commonest fatal accident of
+anæsthesia. The reason why this fact is not more widely recognised
+arises from the natural instinct of any one who has suffered the misery
+and ignominy of causing a death under an anæsthetic, to attribute
+it to some cause beyond human control. The <i>essential</i> cause
+of secondary syncope is failure to maintain a free air way, which
+cannot be styled unavoidable. Two consolations may, however, honestly
+be offered to the person who has acted as anæsthetist in a case of
+secondary syncope. Firstly, it is, in certain types of cases, very
+difficult indeed to maintain a free air way; and secondly, a heart with
+muscle degenerated from fatty or other changes, may give out after very
+little respiratory embarrassment.</p>
+
+
+<h4 class="smcap">Syncope from Overdose.</h4>
+
+<p>This is a more gradual affair than the two foregoing; and has been
+sufficiently dealt with in the chapter devoted to the Stages of
+Anæsthesia (see p. <a href="#Page_36">36</a>).</p>
+
+<p><span class="pagenum" id="Page_145">[145]</span></p>
+
+
+<h3 class="smcap"><b>C. Reflex Syncope.</b></h3>
+
+<p>Exceptionally, a patient not overdosed with anæsthetic, and not
+suffering from any mechanical obstruction to respiration, has a sudden
+attack of syncope during the progress of the operation. We here exclude
+patients who are suffering from surgical shock; the condition arises
+too rapidly for such an explanation to be accepted. Much speculation
+has been expended upon these cases. One view is that some procedure of
+the surgeon has set up a reflex inhibition of the heart through the
+vagus; another, that the reflex has taken the form of sudden vasomotor
+paresis. Levy would ascribe the condition to cardiac fibrillation.
+It may well be that all cases cannot be met by one explanation. The
+older surgeons stoutly maintained that reflex syncope could not arise
+if the patient were properly under, and that it was in the practice
+of those anæsthetists who were afraid of pushing the anæsthetic
+sufficiently, that such accidents occurred. The author’s own belief
+is that a <i>very</i> light chloroform anæsthesia does pre-dispose to
+this accident, but that it may occur also at a deep, the very deepest
+possible level. With an anæsthetic other than chloroform, it is
+extremely rare—perhaps unknown.</p>
+
+
+<h3><b>Treatment of Syncope.</b></h3>
+
+<p>This must be speedy to be of any avail. The following are the points
+upon which to concentrate:—</p>
+
+<div class="blockquot">
+
+<p>(1) <i>Withdraw the anæsthetic.</i></p>
+
+<p>(2) Make sure that the <i>air way is free</i>.</p>
+
+<p>(3) Begin <i>artificial respiration</i> by Sylvester’s method,
+the movement of <i>expiration</i> being first performed
+(<i>see</i> Fig. <a href="#i_p146">48</a>).</p>
+
+<p>(4) <i>Lowering of the head and shoulders</i> is usually to be
+recommended. It is best done by tilting the whole table as if
+for the Trendelenberg position.</p>
+
+<p>The lowering of the head attracts more blood to the<span class="pagenum" id="Page_146">[146]</span> carotid
+artery and raises the blood pressure of the main vessel and
+its cerebral branches (<i>see</i> Fig. <a href="#i_p110">35</a>). It must, however,
+be remembered that it will also tend to empty the blood in the
+veins of the lower extremities and abdomen into the right side
+of the heart, and cases in which marked cyanosis has preceded
+pallor, are probably suffering already from engorgement and
+dilatation of the right heart. The tilting of the table should
+in such cases be very moderate in degree, and should not be
+persisted in if it seems to do no good. In no case, indeed,
+should the tilting be extreme. An angle of more than 15 or 20
+degrees is as likely to do harm as good.</p>
+</div>
+
+  <div class="figcenter" id="i_p146" style="max-width: 484px">
+     <img
+    class="p1"   
+    src="images/i_p146.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 48a.</span>—Artificial respiration by
+Sylvester’s method. Expiration.</p>
+     </div>
+
+<div class="blockquot">
+
+<p>(5) Hot cloths may be placed over the precordial region, care
+being taken not to burn the skin.</p>
+
+<p><span class="pagenum" id="Page_147">[147]</span></p>
+
+<p>(6) The only <i>drugs</i> likely to be of any avail are
+atropine and strychnine, the former being used with the idea of
+paralysing the terminations of the vagus in the heart muscle,
+the latter as a cardiac tonic and a stimulant to the respiratory
+centre. Some authorities have recommended the injection of
+atropine by a long needle passed into the heart muscle, but
+most are content to give either or both drugs hypodermically.
+Really to paralyse the vagus, a very large dose of atropine is
+required—about ¹⁄₃₀ gr. Strychnine should be given in a dose of
+¹⁄₄₀–¹⁄₃₀ gr.</p>
+</div>
+
+  <div class="figcenter" id="i_p147" style="max-width: 465px">
+     <img
+    class="p1"   
+    src="images/i_p147.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 48b.</span>—Artificial respiration by
+Sylvester’s method. Inspiration.</p>
+     </div>
+
+<div class="blockquot">
+
+<p>(7) In cases where the right heart has certainly been
+over-distended, the expedient of venesection has been tried.
+Some six ounces may be withdrawn from the external jugular or
+one of the veins of the arm.</p>
+
+<p><span class="pagenum" id="Page_148">[148]</span></p>
+
+<p>(8) As a last resort, <i>the heart may be massaged</i>. The only
+practicable route is to open the abdomen (if not already done)
+pass one hand under the left side of the vault of the diaphragm,
+placing the other hand over the precordial region. Between the
+two hands, the heart can first be thoroughly compressed to empty
+its presumably flaccid and over-distended cavities, and then
+lightly massaged. Several cases of recovery from this measure
+are on record.</p>
+</div>
+
+
+<h3><b>Status Lymphaticus.</b></h3>
+
+<p>Before leaving the subject of accidents it may be well to allude
+to this condition, which is also known as status thymicus, and as
+lymphatism.</p>
+
+<p>It is met with mostly in the young, the commonest ages probably being
+five to fifteen years. Certain pathological conditions have been found
+in fatal cases, of which the most important are an enlargement of the
+thymus gland, of various lymph glands, and of the tonsils, including
+the naso-pharyngeal tonsil (adenoids). The heart muscle is frequently
+degenerated. Of the cause of these abnormalities we are as yet in
+doubt. There is some reason to believe that the condition tends to
+disappear with advancing years, if the subject survive.</p>
+
+<p>The most outstanding clinical fact in connection with the disease
+is its tendency to cause sudden death on very little provocation. A
+fright, a sudden exertion, and above all an anæsthetic may cause sudden
+and fatal syncope.</p>
+
+
+<h4 class="smcap">Diagnosis.</h4>
+
+<p>Suspicion that the disease is present may be aroused in several ways.
+The presence of enlarged tonsils and adenoids, combined with general
+enlargement of lymph glands from no obvious cause, and a tendency
+to faint, make a very suggestive picture. “Night-crowing” (a sudden
+attack of laryngeal spasm,<span class="pagenum" id="Page_149">[149]</span> occurring at night, and often repeated
+at intervals) also raises grave doubt. The diagnosis can only be
+established with certainty by an X-ray photograph, when the great
+enlargement of the thymus may be seen in the upper part of the chest.</p>
+
+
+<h4 class="smcap">Anæsthetics in Status Lymphaticus.</h4>
+
+<p>Too frequently the condition has never been suspected, and a fatality
+occurs from sudden syncope, usually during the induction period, but
+occasionally during the progress of the operation. It would, however,
+be fallacious to suppose that an anæsthetic is necessarily fatal even
+to an undoubted case. If the drug (preferably ether) be given with
+great care, and the operation done carefully at a level of anæsthesia
+neither too light nor too deep, there is every reason to believe that
+the danger can be, and often is, successfully averted.</p>
+
+<p>At the same time, it must be understood that in a known case, operation
+should always be avoided or deferred if possible.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_150">[150]</span></p>
+
+<h2>CHAPTER XVII.<br>
+<span class="subhed"><b>THE SEQUELÆ OF ANÆSTHESIA.</b></span></h2></div>
+
+
+<h3><b>Respiratory System.</b></h3>
+
+<p>After operations performed under any form of anæsthesia, even spinal,
+there is always a possibility of pneumonia or bronchitis. The
+anæsthetic itself is not always to blame. The patient has suffered
+trauma and is confined to bed, and may develop a hypostatic pneumonia
+just as a person who has suffered from a fractured thigh so commonly
+does, even though he has had no anæsthetic at all.</p>
+
+<p>It is probable that organisms, capable under certain circumstances of
+causing inflammatory disease of the respiratory tract, are present
+in a large proportion of apparently healthy people. Pneumococci and
+streptococci of varying strains may be grown from nasal or pharyngeal
+secretions of patients who suffer from catarrh of these regions, and
+may reappear upon slight provocation even when prolonged treatment had
+apparently banished them permanently. All that is required to start
+an acute infection of lungs or bronchi, is some factor that depresses
+vitality and lowers body resistance to the organism. And if in addition
+use has been made of an inhalational anæsthetic such as ether, which
+may cause an immediate and fairly acute congestion of the respiratory
+mucous membranes, it is not to be wondered at that serious sequelæ
+follow in a certain proportion of cases.</p>
+
+<p>Laboratory results go to show that ether lowers the opsonic index
+of the blood to pneumococci and streptococci, but without placing
+undue emphasis upon a mere isolated phenomenon such as<span class="pagenum" id="Page_151">[151]</span> that, it is
+plain that the whole conditions of the patient after operation are
+favourable to the occurrence of pneumonia or bronchitis, and that of
+all anæsthetics ether is the most likely to be the determining factor.</p>
+
+<p>Experience gained during the war has thrown a certain amount of light
+upon this subject. Post-anæsthetic bronchitis and pneumonia was
+very prevalent among the wounded, far more so than among civilian
+patients. It is, the author believes, reasonable to attribute this
+fact to several causes. In the first place, the soldier’s life,
+alternating between stuffy billets and wet trenches, predisposed him
+to naso-pharyngeal catarrh of a fairly high degree of infectivity.
+Enthusiastic press representatives might state that you could not take
+cold so long as your feet and legs were always buried in half frozen
+mud, but experience hardly bore out their golden promises. Again, the
+soldier did not improve his catarrh by inveterate cigarette smoking.
+Lastly, military hospitals were large institutions, some under canvas,
+some in huts, some in buildings constructed for other purposes, and
+rapidly altered to the urgent needs of the army. Of whatever type,
+nearly all had one feature in common—many of the surgical wards were a
+long (and draughty) way from the operating theatre.</p>
+
+<p>For the prevention of post-anæsthetic pneumonia, the author offers the
+following tentative suggestions:—</p>
+
+<div class="blockquot">
+
+<p>(1) See that the skin is kept covered up as much as possible
+during the operation and that the patient is not exposed to
+draughts during or after it. Rooms can, and should be, well
+ventilated without cold draughts.</p>
+
+<p>(2) If a patient has an acute or sub-acute naso-pharyngeal
+catarrh, treat it as fully as possible before operation by
+sprays and gargles.</p>
+
+<p>(3) Do not use ether to patients who suffer or recently have
+suffered from such conditions.</p>
+
+<p><span class="pagenum" id="Page_152">[152]</span></p>
+
+<p>(4) Give a hypodermic of morphia and atropine before operation
+as a routine.</p>
+
+<p>(5) In so far as possible, let the patient’s shoulders and head
+be raised by pillows during the early hours of convalescence.</p>
+
+<p>(6) Lastly, remember that while no care will absolutely banish
+these dangerous sequelæ from our practice, the greater care
+and skill shown by the anæsthetist, the less bronchitis and
+pneumonia will appear among his patients. As regards ether, the
+author believes that it is the strength of vapour used, more
+than the duration of the anæsthesia, which counts. It is for
+that, among other reasons, that he has for the induction period,
+no hesitation in recommending a method whereby a small part of
+the requisite ether strength is replaced by chloroform.</p>
+</div>
+
+
+<h3><b>Vomiting.</b></h3>
+
+<p>After an anæsthesia lasting more than a few minutes, it may almost be
+regarded as normal for the patient to vomit once or twice. Usually this
+occurs a few minutes after the administration has ceased. In the case
+of nitrous oxide and oxygen, even this slight disturbance may not occur.</p>
+
+<p>The amount of vomiting which after this stage may be regarded as
+normal is difficult to determine. The author took notes of some 300
+cases on this point. The details of his results are not suitable for
+a text book, but, broadly speaking, it would appear that after an
+operation of ordinary duration and severity, the vomiting returns on
+the average some five or six times, and usually ceases on the evening
+of the operation day. A limited number continue to vomit at intervals
+until the early hours of the following morning. With nitrous oxide
+and oxygen the vomiting is far less than the above, though even with
+this anæsthetic quite severe emesis may occur. With closed-ether, the
+trouble is very violent<span class="pagenum" id="Page_153">[153]</span> for a short time, large quantities of mucous
+being ejected: it is probable that after the first two hours, it is no
+more marked than after open methods. The use of morphia and atropine
+before operation most certainly reduces the violence and duration of
+this sequela.</p>
+
+<p>Prolonged more than twenty-four hours, the condition must be regarded
+as definitely abnormal.</p>
+
+
+<h4 class="smcap">Prevention and Treatment.</h4>
+
+<p>The adoption of open-ether preceded by morphia and atropine and due
+skill and thought on the part of the anæsthetist, combined with proper
+preparation of the patient, are the only means of prevention at our
+command.</p>
+
+<p>The raised position of the head and shoulders during the recovery
+stage undoubtedly tends to reduce the nuisance. It is a vexed question
+whether to give or to withhold fluids after operation—and this matter
+is of course in the hands of the surgeon, not the anæsthetist. In
+certain cases, the author believes that it is worth while trying the
+effect of a cup of fresh tea with very little sugar or milk. Even if
+rejected in a few moments, the astringent effect of the infusion seems
+to soothe the gastric mucous membrane, and give relief.</p>
+
+
+<h3><b>Post-operative Acidosis.</b></h3>
+
+<p class="center">(Synonym—Delayed Chloroform Poisoning).</p>
+
+<p>In a limited number of cases, post-operative emesis assumes a grave
+type, and definitely threatens life. Such cases began to be studied
+in the early part of this century, and though our knowledge of the
+condition is still incomplete, the student should be acquainted with
+the present views held upon the subject.</p>
+
+<p>Clinically, the earliest symptom to raise suspicion, is the
+reappearance of vomiting at a time when one would expect such trouble
+to have abated, usually twenty-four or thirty-six hours<span class="pagenum" id="Page_154">[154]</span> after
+operation. Within a few hours, the nature of the vomit changes from
+the usual bilious stomach contents, and shows obvious evidence of the
+presence of <i>altered blood</i>. The pulse and temperature begin to
+rise, the countenance assumes an anxious look. A trace of jaundice is
+usually present. The nervous system becomes affected as shown first in
+restlessness, and later, delirium. Every degree of this condition is
+possible, but a very large proportion of recognisable cases pass into
+coma, and death supervenes within a few days, sometimes less.</p>
+
+<p>Investigation into such cases has shown that the essential underlying
+condition is an acidosis closely allied to that seen in diabetic coma.
+The breath has the peculiar sweetish aroma of acetone, and acetone,
+diacetic acid, and B. oxybutyric acid successively appear in the urine.</p>
+
+<p>Post-mortem, the most striking change found is a profound fatty
+degeneration of the liver, the cells of which are disintegrated as in
+acute yellow atrophy.</p>
+
+<p>It is obvious from the foregoing that there is present a very
+remarkable abnormality of metabolism. Mr Rendle Short, in his admirable
+book, <i>The New Physiology in Surgical and General Practice</i>, gives
+the following explanation of the condition:—</p>
+
+<p>“The physiological process of dealing with fat is to resolve it into
+carbon di-oxide and water. If we make a pound of fat into tallow
+candles and burn it, we shall obtain carbon di-oxide and water, and a
+certain amount of heat will be evolved. If the pound of fat is eaten
+and absorbed by a man or an animal, it will be burnt to the same end
+products, and the same amount of heat will be given out. But in certain
+circumstances, an abnormal mode of breaking down is followed, and
+there are produced, first B. oxybutyric acid, then diacetic acid, and
+finally acetone. If this takes place on a large scale, the conversion
+into acetone fails to keep pace with the production of acids. Therefore
+first acetone appears in the urine, then diacetic acid, and finally<span class="pagenum" id="Page_155">[155]</span>
+oxybutyric acid; the last may rise rapidly to an enormous figure: 30,
+50, or even 180 grams may be passed daily.”</p>
+
+<p>Later in the same chapter, Short propounds the question as to what are
+the special circumstances in which the breaking down of fat deviates
+from its normal course, and follows this dangerous route. The answer
+is, he says, quite definite and decisive. When the tissues are unable
+to obtain sugar from the blood, fat is broken down <i>via</i> these
+dangerous acids to acetone, instead of to carbon di-oxide and water.</p>
+
+<p>Such an inability on the part of the tissues to obtain sugar arises
+under several conditions:—</p>
+
+<div class="blockquot">
+
+<p>(<i>a</i>) In diabetes, where sugar though freely present in
+the blood cannot, for some reason still not clearly known, be
+assimilated by the tissues.</p>
+
+<p>(<i>b</i>) In poisoning by salicylates.</p>
+
+<p>(<i>c</i>) In starvation, for obvious reasons. The supply of
+sugar from the liver has been used up, and the patient, living
+on his own fats, breaks them up abnormally.</p>
+
+<p>(<i>d</i>) In post-anæsthetic poisoning, for reasons which are
+at present not clearly ascertained.</p>
+</div>
+
+<p>Upon the theoretical side it is therefore not possible to say more than
+that anæsthetics sometimes initiate this abnormal metabolic process. To
+the question as to why and how they do so, we can as yet give no answer.</p>
+
+<p>Upon the practical side, we can, however, speak much more definitely.
+Acidosis follows the use of ether very rarely indeed: after nitrous
+oxide it is unknown. Chloroform has been the drug used in almost every
+recorded case, while ethyl chloride has been responsible in a few
+isolated instances. Young children are much more prone to suffer than
+adults, though the author had a fatal case in a lady well over forty
+years of age: he has also seen a case very nearly fatal in a soldier
+aged twenty. This man<span class="pagenum" id="Page_156">[156]</span> was, a week after recovery from acidosis,
+anæsthetised for half-an-hour with nitrous oxide and oxygen, without
+exhibiting any signs of a return of his dangerous condition. Anæsthesia
+repeated in the same subject after a short interval is more prone
+to start the process than a first inhalation. Lastly, acute sepsis,
+particularly in the young, is notorious for its liability to be
+followed by acidosis.</p>
+
+
+<h4 class="smcap">Prevention and Treatment.</h4>
+
+<p>The obvious moral of the foregoing is that chloroform should not be
+administered to patients suffering from acute sepsis, particularly if
+they be very young. Indeed, so common is a mild degree of acidosis
+among children, some surgeons consider there is a definite risk in
+giving chloroform to them at all unless special precautions are taken.
+Chief among these are regular dosage for a day or two before operation,
+with considerable doses of bicarbonate of soda and sugar, which is a
+routine measure in some children’s hospitals.</p>
+
+<p>As regards curative treatment, much can be done if the gravity of the
+condition is recognised early. The stomach is first washed out with
+alkalis, and a substantial dose (one dram) of bicarbonate of soda left
+in it. The same dose is repeated hourly by the mouth, if retained, or
+per rectum. A useful addition to the alkaline treatment is dextrose,
+also in teaspoonful doses. In grave cases, these drugs should be given
+intravenously in saline solution.</p>
+
+<p>These measures combined with warmth, and ample fluids by mouth or
+rectum, will often save life, but to be of any value they must be
+begun early. Fulminating cases occur which succumb rapidly in spite of
+treatment.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_157">[157]</span></p>
+
+<h2>CHAPTER XVIII.<br>
+<span class="subhed"><b>POSTURE OF THE PATIENT.</b></span></h2></div>
+
+<p>The position in which the patient is lying is of as much importance to
+the anæsthetist as to the surgeon. It is for the surgeon to say what
+he wants and for the anæsthetist to realise how his own work will be
+thereby affected.</p>
+
+
+<h3><b>Dorsal Decubities.</b></h3>
+
+<p>This is the ordinary position and calls for no extended comment. The
+pillows must be so arranged that at no spot is the body acutely flexed
+or extended. Abdomen, thorax, neck, and head must all be roughly in a
+straight line.</p>
+
+<p>Deep-chested subjects require a higher pillow than those with shallow
+chests, otherwise the neck is bent back and respiration obstructed.</p>
+
+<p>The arms should either be folded and retained by a bandage or other
+device over the chest, or extended so that the hands can be slipped
+under the buttocks and retained there by the body weight. An arm which
+is allowed to hang over the side of the table is likely to show next
+day and for many months afterwards, the condition of drop-wrist from
+musculo-spiral paralysis.</p>
+
+
+<h3><b>Face-down Position.</b></h3>
+
+<p>This is an awkward position for the anæsthetist; there being a general
+tendency to respiratory embarrassment. Put a pillow under the upper
+part of the thorax, leaving the lower part and the abdomen as free as
+possible. Let the head project from the pillow, so that the face can be
+got at without undue rotation of the neck. The intratracheal method is
+a great help.</p>
+
+<p><span class="pagenum" id="Page_158">[158]</span></p>
+
+
+<h3><b>Lateral Position.</b></h3>
+
+<p>This may be called for either with or without the addition of a
+sand-bag or inflatable air-pillow to push the loin upwards. In either
+case, there is a tendency for the upper shoulder to fall forwards, the
+position then assimilating itself to the face-down position. This is
+best met by a support fixed to the table, upon which the upper arm may
+be rested. Failing such a convenience, a sand-bag may be pushed in to
+keep up the shoulder, or the assistance of a nurse may be required.</p>
+
+
+<h3><b>The Trendelenburg Position.</b></h3>
+
+<p>Slight tilting of the head end of the table downwards is often useful
+in assisting the return of bowel into the abdomen: in this position,
+the patient usually takes the anæsthetic very well. It must not be
+assumed until the third stage of anæsthesia is reached.</p>
+
+<p>For many gynæcological operations, however, the full Trendelenburg
+position is required. Healthy subjects usually do quite well in it, but
+stout persons not uncommonly show a good deal of cyanosis. At the close
+of the operation it is essential to restore the table to the horizontal
+<i>slowly</i>: the physics of the circulation are profoundly modified,
+and if any serious degree of shock is present, rapid return to normal
+may initiate a collapse.</p>
+
+<p>In the full position, the weight of the body should be taken by metal
+supports attached to the table against which the shoulders may rest. To
+hang the entire weight of the body upon the legs may cause a good deal
+of after-suffering to the patient.</p>
+
+
+<h3><b>The Sitting-up Position. (<i>See</i> Fig. <a href="#i_p159">49</a>.)</b></h3>
+
+<p>The object of this position is to diminish venous engorgement and
+bleeding in operations requiring delicate dissection in the region of
+the neck. Prof. Alexis Thomson introduced the position into Edinburgh
+surgery: the author was at first rather nervous of<span class="pagenum" id="Page_159">[159]</span> it, but has found
+that with proper precautions the patients do uncommonly well. Beyond
+all doubt, the position is a great help to the work of the surgeon.</p>
+
+<p>Not every surgical table is capable of giving the full position without
+the use of many pillows and sandbags. The head-piece of the table is
+tilted up at an angle of about 75° or even 80°, and the patient pulled
+up so that the flexion of the body occurs in the lumbar, not the dorsal
+spine. A small sand-pillow is placed behind the neck so as to produce
+slight extension. Another heavier one is placed under the thighs to
+prevent the body slipping down. A slight tilt downwards towards the
+head end may be given to the table as a whole with the same object.</p>
+
+  <div class="figcenter" id="i_p159" style="max-width: 462px">
+     <img
+    class="p1"   
+    src="images/i_p159.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 49.</span>—Sitting-up posture for operations on
+the neck.</p>
+     </div>
+
+<p>One should not in this position attempt to induce a deep chloroform
+anæsthesia. Weak C.E. mixture at most, but better simply open-ether is
+the method of choice. The induction is<span class="pagenum" id="Page_160">[160]</span> begun with the shoulders raised
+to a modified degree, and the full position assumed in a light third
+stage anæsthesia.</p>
+
+<p>Intratracheal ether combined with this position is an ideal anæsthesia
+for the removal of goitre or extensive dissections in the neck for
+enlarged glands.</p>
+
+
+<h3><b>O’Malley’s Position for Nasal Surgery. (<i>See</i> Fig. <a href="#i_p160">50</a>).</b></h3>
+
+<p>The author became acquainted with this useful position while acting as
+Anæsthetist at the Royal Herbert Hospital, Woolwich, where the Nose
+and Throat Department was under the charge of Major O’Malley, F.R.C.S.
+Major O’Malley was kind enough in a recent letter written by request to
+refresh the author’s memory of the details.</p>
+
+  <div class="figcenter" id="i_p160" style="max-width: 578px">
+     <img
+    class="p1"   
+    src="images/i_p160.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig. 50.</span>—O’Malley’s posture for intra-nasal
+surgery.</p>
+     </div>
+
+<p>With the patient lying as shewn in the photograph, every part of the
+interior of the nose can be easily inspected by the surgeon; the
+elevation of the head and shoulders prevents undue bleeding, and
+such hæmorrhage as does occur goes down the gullet, where it does no
+particular harm, instead of into the larynx. The degree<span class="pagenum" id="Page_161">[161]</span> of flexion
+of the head upon the neck is not so extreme as to interfere with
+respiration.</p>
+
+<p>The details of O’Malley’s procedure are as follows:—</p>
+
+<p>The interior of the nasal cavities are packed with gauze soaked in
+adrenalin and novocain a quarter of an hour before operation, and the
+patient receives a very small dose of morphia and atropine immediately
+before anæsthesis is induced; given in this way it does not complicate
+the induction with chloroform to the same extent as if given earlier.
+The patient lies with the top of the head level with the top of the
+table, and the head and shoulders (including the upper two-thirds of
+the shoulder blades) supported on the usual depth of pillow. Induction
+is by chloroform or mixture; a very light third stage only is aimed
+at. When it is attained the mouth is opened by a gag, and Phillip’s
+Oral Airway inserted (<i>see</i> Fig. <a href="#i_p023b">8</a>). Strict oral respiration is
+essential to success. If air is passing in and out of the nose, blood
+is spluttered all over the surgeon, seriously interfering with the
+harmony of the proceedings. Junker’s chloroform bottle is ready, and
+the end of the supply pipe is passed into one of the side holes in the
+air way.</p>
+
+<p>The head of the table is now elevated to an angle of 45°, and a small
+sand pillow slipped behind the occiput. The gauze is removed from the
+nose, and the operation can be performed with great comfort.</p>
+
+<p>The circulation of the patient needs careful watching for the first
+minute or two after the table head has been elevated, but thereafter
+there is usually no special cause for anxiety. The area of operation
+is locally anæsthetised by the action of the novocain and a light
+chloroform sleep only is required.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_162">[162]</span></p>
+
+<h2>CHAPTER XIX.<br>
+<span class="subhed"><b>CHOICE OF ANÆSTHETIC.</b></span></h2></div>
+
+<p>In considering this matter, some repetition of points to which
+reference has already been made, is inevitable. Indeed, this chapter
+may be regarded as a revision of the whole subject.</p>
+
+<p>Before deciding upon drug and method suitable for the individual case,
+we must consider the age and sex, the physical type and temperament,
+the possible presence of some definite pathological condition, and the
+nature and duration of the operation.</p>
+
+<p>In relation to this last point, we must remember that an anæsthesia
+must be adequate to the purpose of the surgeon, but that it is improper
+to incur more risk to life than is necessary. For instance, an
+abdominal section case must be fully relaxed, and if in an individual
+case, chloroform is the only drug which will give that effect, there
+need be no hesitation in using it. On the other hand, many other
+methods with a far smaller mortality rate are available if all that is
+required is the extraction of a tooth or the incision of an abscess,
+and in that group of cases, unfamiliarity with such anæsthetics as
+nitrous oxide or “ethyl chloride and ether” will not be held as a
+sufficient defence if chloroform has been given with a fatal effect.</p>
+
+
+<h3><b>Normal Subjects.</b></h3>
+
+<p>Let us take first the case of the healthy adult about to undergo a
+<i>major</i> operation. For this, we unhesitatingly choose what we may
+term the “stock” method—open-ether preceded by morphia and atropine.</p>
+
+<p><span class="pagenum" id="Page_163">[163]</span></p>
+
+<p>If the operation be <i>brief</i>, we have a choice of methods. For
+the extraction of teeth, where access to the mouth is essential, the
+following table will help:—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctrtrbl smcap">Anæsthetic Drug and Method.</td>
+    <td class="ctrtrb">Duration of Available Anæsthesia, when given as “Single<br>Dose.”</td>
+    <td class="ctrtrb smcap">Remarks.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Nitrous oxide</td>
+    <td class="chtr">30 to 40 seconds</td>
+    <td class="chtr"></td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Nitrous oxide and<br>oxygen</td>
+    <td class="chtr">40 to 50 seconds</td>
+    <td class="chtr"></td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Ethyl chloride</td>
+    <td class="chtr">70 to 90 seconds</td>
+    <td class="chtr">Only to be recommended in special cases (<i>see</i> page <a href="#Page_127">127</a>).</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Gas and ethyl chloride</td>
+    <td class="chtr">70 to 90 seconds</td>
+    <td class="chtr"></td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Gas-oxygen and ethyl<br>chloride</td>
+    <td class="chtr">70 to 90 seconds</td>
+    <td class="chtr"></td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Gas and ether</td>
+    <td class="chtr">Anything up to 2 to 5 minutes according to duration of inhalation</td>
+    <td class="chtr">May cause after vomiting.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Ethyl chloride and ether</td>
+    <td class="chtr">Anything up to 2 to 5 minutes according to duration of inhalation</td>
+    <td class="chtr">May cause after vomiting. More portable.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Nasal gas</td>
+    <td class="chtr">5 to 10 minutes (not a “single dose” anæsthetic)</td>
+    <td class="chtr">Requires considerable practice to give well.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrbl">Nasal gas and oxygen</td>
+    <td class="chtrb">No limit</td>
+    <td class="chtrb">Easier to give than above but apparatus rather importable.</td>
+  </tr>
+</table>
+
+<p>In cases where access to the mouth is not required, and where it is
+therefore unnecessary to “charge up” the patient with anæsthetic, we
+have also a choice which may be expressed tabularly:—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctrtrbl smcap">Anæsthetic.</td>
+    <td class="ctrtrb smcap">Remarks.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Nitrous oxide</td>
+    <td class="chtr">Apparatus simple: short administration can be
+mastered easily. A little more practice required
+for cases prolonged by admitting air. Muscles
+not relaxed, and patient may move when cut.<span class="pagenum" id="Page_164">[164]</span></td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Nitrous oxide and oxygen</td>
+    <td class="chtr">Apparatus more complicated, but short administrations
+ present no great difficulty to the beginner.    |
+ Muscles not completely relaxed unless a little   |
+ ether added.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Gas and ether</td>
+    <td class="chtr">Quick and safe anæsthetic. Deep anæsthesia
+ may be obtained if ether is “pushed.”</td>
+  </tr>
+
+  <tr>
+    <td class="chtrbl">Ethyl chloride and ether</td>
+    <td class="chtrb">The same. More portable than above.</td>
+  </tr>
+</table>
+
+<p>In this group of short operations, special reference must be made to
+the <i>reduction of dislocations</i>. Here two important features
+require notice. The whole object of the proceeding is to relax muscles,
+and therefore nitrous oxide or gas-oxygen are unsuitable. Secondly,
+the tendency to reflex syncope just at the moment of reduction is very
+great. For this reason, chloroform has here a painfully high mortality
+rate; closed-ether, preceded by gas or ethyl chloride, is undoubtedly
+the method of choice.</p>
+
+
+<h3><b>The Extremes of Age.</b></h3>
+
+<p>Children up to the age of ten years take ether badly, salivation
+and bronchial secretion being sometimes very troublesome. Atropine
+mitigates this nuisance to a limited degree only. Chloroform is the
+best drug up to five or six years; from five to ten, mixture; after
+that, open ether.</p>
+
+<p>In children of any age, suffering from acute sepsis, the immediate
+annoyances and possible respiratory sequelæ of ether must be faced
+(<i>see</i> page <a href="#Page_156">156</a>), owing to the probability of acidosis.</p>
+
+<p>As regards short anæsthetics in children, nitrous oxide, if given at
+all, should be freely diluted with oxygen, otherwise most undesirable
+cyanosis will occur. To children under three or four, even gas-oxygen
+is of doubtful safety. Short anæsthesias in such cases may be induced
+by open ethyl chloride, with a few drops of ether added.</p>
+
+<p><span class="pagenum" id="Page_165">[165]</span></p>
+
+<p>Old people are, unless very feeble, best anæsthetised by a mixture of
+chloroform and ether. Whatever anæsthetic be chosen, the utmost care
+must be taken to avoid cyanosis. A cylinder of oxygen should be at hand
+from which to enrich the atmosphere breathed, by trickling the gas into
+the mouth through a rubber tube, and is a great safeguard in dealing
+with the old.</p>
+
+
+<h3><b>Sex.</b></h3>
+
+<p>On the average, women take anæsthetics much better than men, being far
+less liable to jaw clenching and other forms of mechanical asphyxia,
+and showing less excitement during the induction stage. In the female
+subject induction by open-ether requires very little assistance from
+C.E. mixture.</p>
+
+
+<h3><b>Physical Type and Temperament, and Habits of Life.</b></h3>
+
+<p>Heavily built muscular men are troublesome subjects. Induction requires
+a rather strong vapour of ether: if the open method is used, there may
+be to the beginner much temptation to make use during the induction
+stage of C.E. mixture to an extent not contemplated in the description
+given of that method in chapter <span class="allsmcap">IX.</span>: it is therefore wise to
+induce either with closed-ether or with C.E. mixture as described in
+chapter <span class="allsmcap">XV.</span>, and to change to the perhalation method only when
+full anæsthesia is attained.</p>
+
+<p>As regards alcoholics and excessive smokers, these are well dealt with
+by the C.E. open-ether sequence. Recourse may be made to the Ormsby
+inhaler as already explained on page 137. The reader is warned not to
+be deceived by the stout, rosy face of the typical alcoholic. He often
+looks a great deal stronger than he really is. Many such are really
+feeble subjects: although they shout and struggle no great addition
+to the usual vapour strength of anæsthetic is safe or required: what
+<i>is</i> required, is a little extra time. Once fully under, the
+robust appearance of the<span class="pagenum" id="Page_166">[166]</span> patient disappears, and the fact that one is
+dealing with a rather broken constitution and a poor circulation is
+obvious.</p>
+
+<p>Reference has already been made to the fact that persons with defective
+nervous systems, neurotics, and especially epileptics, show persistence
+of some muscular movements for some time, and therefore require very
+careful watching.</p>
+
+
+<h3><b>Special Operations and Pathological Conditions in the Patient.</b></h3>
+
+<p>These are of the utmost importance, but to consider each fully from
+the anæsthetic point of view, would lead us into great detail. The
+anæsthetist must acquaint himself with any abnormality present, and
+consider it carefully in the light of the general principles already
+explained. The following very brief hints for selected cases and
+operations may, however, be found useful.</p>
+
+
+<h4 class="smcap">Upper Air Passages.</h4>
+
+<p><i>Artificial teeth.</i> Must be removed before inducing.</p>
+
+<p><i>Tongue and jaw cases.</i>—Intratracheal ether the best—failing
+that, rectal oil ether, or Junker’s inhaler.</p>
+
+<p><i>Nasal operations.</i>—If adrenalin is to be used, it must precede,
+not follow, chloroform—many fatalities have occurred from injecting
+or even packing with adrenalin in light chloroform narcosis. Some
+surgeons object to ether because of the bleeding, but this can be
+largely remedied by raising the head and shoulders, and by packing with
+adrenalin. Many surgeons prefer local to general anæsthesia.</p>
+
+<p><i>Nasal insufficiency.</i>—Don’t allow a patient to continue to make
+ineffectual attempts to breathe through a narrow nose. Establish mouth
+breathing, or use Silk’s tubes (<i>see</i> Fig. <a href="#i_p023c">9</a>).</p>
+
+<p><i>Tonsils and adenoids.</i>—Give ethyl chloride by the vapour method.</p>
+
+<p><i>Tumours and inflammatory swellings obstructing respiration.</i>—<span class="pagenum" id="Page_167">[167]</span>
+Don’t use closed methods. Have tracheotomy instruments at hand, and a
+cylinder of oxygen.</p>
+
+<p><i>Gôitres, especially exophthalmic gôitre.</i>—Don’t use chloroform:
+it has caused many fatalities; morph-atropine, followed by open-ether
+is the safest. In bad cases, use rectal oil ether if intratracheal is
+not available. The “sitting up posture” is a great help (<i>see</i>
+page <a href="#Page_168">168</a>). Use anoci-association if surgeon is willing.</p>
+
+
+<h4 class="smcap">Chest.</h4>
+
+<p><i>Bronchitis and pneumonia</i> (<i>see</i> remarks in chapter
+<span class="allsmcap">XVII</span>).</p>
+
+<p><i>Emphysema and rigid chest wall.</i>—Patients take anæsthetics
+badly; they cyanose quickly, the abdominal wall cannot be made either
+lax or quiet, since the patient’s natural method of respiration is
+abdominal rather than thoracic. Lastly, there is frequently a dilated
+heart with degenerate cardiac muscle, giving an abnormal tendency to
+secondary syncope. Give a trickle of oxygen through a tube from a
+cylinder: don’t be tempted to overdose with anæsthetic in the vain hope
+of securing ideal relaxation of the abdominal wall.</p>
+
+<p><i>Empyæma.</i>—Be careful: a good many accidents have happened. Use
+chloroform with added oxygen: aim at an anæsthesia just deep enough
+to prevent straining which might rupture the empyæma into the lung
+and drown him in his own pus. Withdraw the anæsthetic as soon as the
+abscess is opened.</p>
+
+<p><i>Phthisis.</i>—Don’t use closed-ether: it may start
+hæmorrhage—open-ether rarely does any harm unless the condition is
+very acute.</p>
+
+
+<h4 class="smcap">Circulatory System.</h4>
+
+<p><i>High tension, arterio-sclerosis, and aneurysm.</i>—Avoid pure
+nitrous oxide: in severe cases, C.E. mixture and oxygen is the safest.</p>
+
+<p><i>Heart.</i>—Well compensated cases of <i>valvular disease</i>
+take chloroform or open-ether well, provided a free air-way is
+maintained.<span class="pagenum" id="Page_168">[168]</span> Closed methods should be avoided. Cases of <i>myocardial
+disease</i> with dilated cavities present special dangers. Open-ether
+with added oxygen meets the case better than any other anæsthetic.
+<i>Pericarditis</i>, both acute and chronic, has been found as the
+determining factor in many anæsthetic fatalities.</p>
+
+
+<h4 class="smcap">Acute Infectious Disease.</h4>
+
+<p><i>Febrile patients</i> absorb anæsthetics very rapidly and therefore
+go under very quickly. Acute septic cases must not have chloroform
+or ethyl chloride (<i>see</i> page <a href="#Page_155">155</a>): nitrous oxide and oxygen is
+ideal, ether the next best. Patients who have suffered from acute
+infectious disease, especially diphtheria and influenza, may present
+some weakness of heart muscle for many months after the attack.</p>
+
+
+<h4 class="smcap">Exhausted and Shocked Cases.</h4>
+
+<p>Give nitrous oxide and oxygen if possible—failing that, ether.
+Closed-ether sometimes does very well for the induction stage.</p>
+
+
+<h4 class="smcap">Diabetes.</h4>
+
+<p>Chloroform is wholly inadmissible.</p>
+
+
+<h4 class="smcap">Genito-urinary System.</h4>
+
+<p><i>Kidneys.</i>—Avoid ether in acute or sub-acute nephritis: give it,
+however, for nephrectomy when the other kidney is sound.</p>
+
+<p><i>Bladder.</i>—Distending the bladder with lotion often causes reflex
+inhibition of respiration: if that happens, stop the anæsthetic, give
+artificial respiration, and ask the surgeon to get on with opening
+the bladder. <i>Morphia</i> usually arrests temporarily the secretion
+of urine: it should therefore not be given if chromocystoscopy or
+catheterisation of the ureters is contemplated.</p>
+
+<p><i>Prostatectomy cases</i> are often rather broken subjects: give
+a fairly deep anæsthesia until the shelling out of the prostate is
+begun: then be careful—the patient is breathing deeply as a rule,<span class="pagenum" id="Page_169">[169]</span>
+and can readily get an overdose. He will inevitably suffer a fair
+amount of shock: be ready to lower the table at the head end if any
+serious collapse occurs. Don’t be shy of starting a little artificial
+respiration even though the natural function is not entirely abolished.</p>
+
+<p><i>Circumcision</i> usually causes a good deal of laryngeal spasm,
+especially in children. Don’t try to abolish this by deepening the
+anæsthesia. You won’t succeed unless you nearly kill the patient. Rub
+the lips, and if very severe ask the surgeon to stop a minute until the
+crowing becomes less.</p>
+
+<p><i>Castration.</i>—Always give ether, or gas-oxygen. Castration and
+reduction of dislocation are the two commonest causes of reflex syncope
+under chloroform.</p>
+
+
+<h4 class="smcap">Menstruation, Pregnancy, and Labour.</h4>
+
+<p>It is usual to avoid anæsthetics during the menstrual period if
+possible, the nervous system being unlikely to be at its best at that
+time.</p>
+
+<p>Pregnant patients take no harm from an anæsthetic properly given,
+but undue cyanosis must be avoided or abortion may occur. The pains
+of labour may be alleviated by chloroform given to an early second
+stage only, or by “twilight sleep” (<i>see</i> page <a href="#Page_44">44</a>). For the major
+operations of obstetrics, however, ether has its usual advantages,
+provided no bronchitis be present. The shock of such operations as a
+difficult version is considerable, and quite sufficient to call for
+ether rather than chloroform.</p>
+
+<div class="blockquot">
+
+<p><i>Indication for Local and Spinal Anæsthesia.</i>—The
+foregoing has been written in reference to inhalational
+anæsthesia solely. Mr Wood has indicated in chapters
+<span class="allsmcap">XX.</span> and <span class="allsmcap">XXI.</span> the class of case in which the
+methods he describes are to be preferred.</p>
+</div>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_170">[170]</span></p>
+
+<h2>CHAPTER XX.<br>
+<span class="subhed"><b>LOCAL ANÆSTHESIA.</b></span></h2></div>
+
+<p>By the term local anæsthesia, or more correctly <i>local analgesia</i>,
+is meant the loss of sensibility to painful stimuli without loss of
+general consciousness. It may be induced in a considerable number
+of ways, but for practical purposes there are only four methods of
+value:—(1) by infiltration of the tissues to be operated upon by a
+solution of the drug, (2) by injecting the solution into or around
+the nerve trunks supplying the part, (3) by painting the solution on
+a mucous surface, and (4) by the application of intense cold. The
+last method has only a limited application. The method of injecting
+the anæsthetic into the blood vessels of the part is still in the
+experimental stage and is not to be recommended for general use.</p>
+
+<p>It is advisable first to consider the behaviour of the principal drugs
+which are employed.</p>
+
+
+<h3><b>Cocaine.</b></h3>
+
+<p>This was the first drug to be widely used for the production of
+local anæsthesia. It is an alkaloid occurring in the leaves of
+<i>Erythroxylon Coca</i>. It is only slightly soluble in water—about
+1 in 1300, but the hydrochloride of cocaine is freely soluble, and it
+is this salt that is commonly used for aqueous solutions. The solutions
+do not keep well, and should be made up shortly before being used. The
+drug is decomposed by boiling.</p>
+
+<p><span class="smcap">Action.</span>—When a solution of cocaine is injected into the
+tissues, the sensory nerve endings become anæsthetic over the area into
+which the drug penetrates, direct paralysis of the nerve<span class="pagenum" id="Page_171">[171]</span> terminals
+being produced. When it is injected into or around a nerve trunk it
+blocks the transmission of nerve impulses. When it is applied locally
+to a mucous membrane, it produces, besides a loss of sensation, a
+feeling of constriction and a distinct pallor and contraction of the
+vessels, which point to a local action on the vessel walls. The drug is
+very frequently applied to the eye. There it produces not only local
+anæsthesia, but also contraction of the conjunctival vessels, and this
+is followed by dilatation of the pupil and often by partial loss of the
+power of accommodation.</p>
+
+<p><span class="smcap">Cocaine Poisoning.</span>—Certain patients show an idiosyncrasy
+to the action of cocaine, and the greatest care must be exercised
+in its use. Absorption of small quantities usually causes mental
+excitement. The patient becomes restless and garrulous, and a feeling
+of happiness may be produced, but in other cases the patient becomes
+anxious and confused. In some patients a small dose is followed by a
+calm languorous state, resembling that produced by morphia, but with
+less tendency to sleep. The pulse is accelerated, the respiration is
+quick and deep, and the pupils are dilated. When poisonous doses have
+been administered, the heart becomes extremely accelerated, powerful
+tonic or clonic convulsions supervene, the breathing becomes rapid
+and shallow, and may be finally arrested during a convulsion. In some
+cases a different set of symptoms are observed, fainting and collapse
+occur, and convulsive seizures are almost entirely absent. The heart
+is slow and and weak, the respirations are slow and shallow, the skin
+is cyanotic and cold, and death takes place from gradual arrest of
+respiration.</p>
+
+<p><span class="smcap">Treatment.</span>—The treatment consists in endeavouring to
+encourage the action of the heart by every possible means. The patient
+is placed flat on his back, if he is not already in this position,
+hypodermic injections of ether and strychnine are administered, and hot
+coffee given by the mouth; warmth is of<span class="pagenum" id="Page_172">[172]</span> great importance. Artificial
+respiration is commenced if respiration begins to fail. There is no
+specific antidote to cocaine.</p>
+
+<p><span class="smcap">Dosage.</span>—The maximum dose of cocaine that can be given with
+safety is 3/4 of a grain. The amount of solution that may be employed
+depends upon the strength. To make a 1 per cent solution, 1 gr. of
+cocaine hydrochloride is dissolved in 110 minims of distilled water
+or half strength normal saline; from these proportions the amount of
+cocaine in a given solution can be calculated. It will be seen that
+the amount of cocaine solution, even with strengths as weak as ½ or ¼
+per cent, that can be used with safety is small and insufficient to
+anæsthetise an area of any great extent. Owing to its toxicity cocaine
+has largely fallen out of use for the production of infiltration or
+regional anæsthesia, though it is still widely used in ophthalmic
+surgery and in the surgery of the ear, nose and throat.</p>
+
+
+<h3><b>Novocaine.</b></h3>
+
+<p>This drug is immensely superior to cocaine for ordinary surgical
+purposes. It is the hydrochloride of a synthetic base, its chemical
+formula being C<sub>13</sub>H<sub>20</sub>N<sub>2</sub>O<sub>2</sub>, HCl. It is soluble in water 1
+in 1, and can be heated to 120°C without decomposition. Its solutions
+possess slight antiseptic properties, and are capable of repeated
+boiling without affecting their strength. They may be kept for several
+months without suffering any change in their action, a quality not
+possessed by any other anæsthetic agent.</p>
+
+<p>The <i>toxicity</i> of novocaine is one-fifth or one-seventh of that
+of cocaine. When used in conjunction with adrenalin, its anæsthetic
+activity is equal to that of cocaine. When injected into the tissues
+it produces no irritant effects like certain other local anæsthetics,
+notably stovaine. For the production of local anæsthesia it is used in
+½ per cent. solution with the addition of three or four minims of 1 in
+1000 solution of adrenalin chloride to each ounce.<span class="pagenum" id="Page_173">[173]</span> Several ounces of
+this preparation may be used with the greatest safety.</p>
+
+<p>Allen makes the following statement regarding this drug:—“After a
+rather extended experience, including a large number of cases embracing
+the entire field of surgery, in which this agent has been almost
+exclusively used, we have failed to note a single case in which there
+has been any unpleasant local or constitutional action. We, therefore,
+feel thoroughly justified in unqualifiedly recommending it as the
+safest, most reliable, and satisfactory of any local anæsthetic agent
+yet introduced.”</p>
+
+
+<h3><b>Tropacocaine.</b></h3>
+
+<p>This drug was first isolated from the leaves of the coca plant of Java,
+but is now prepared synthetically. Its formula is C<sub>15</sub>H<sub>19</sub>NO<sub>2</sub>.
+Its action is exactly the same as that of cocaine, except that it
+is one-half as toxic and the duration of anæsthesia is shorter. The
+hydrochloride is freely soluble in water, and can be boiled without
+fear of decomposition. It is the agent which is most suitable for
+spinal anæsthesia, as fewer unpleasant effects have followed its use
+than that of any other drug.</p>
+
+
+<h3><b>Stovaine.</b></h3>
+
+<p>Stovaine is the hydrochloride of a synthetic compound of the benzoyl
+group. It occurs as a white crystalline powder, soluble in water, 1 in
+14. Its solutions withstand boiling, but are decomposed when heated
+to 120°C. Its action is the same as that of cocaine, except that it
+is slightly less toxic and less powerful. It has a distinct irritant
+effect locally. When injected in dilute solution, it produces a slight
+burning pain before anæsthesia appears, and very often a distinct
+inflammatory reaction persists for some time after the operation. It is
+therefore unsuited for local anæsthesia. It has been widely used for
+the production of spinal anæsthesia, especially by the French school,
+but since its injurious effects on<span class="pagenum" id="Page_174">[174]</span> nerve tissues have become more
+apparent, it has been less used than formerly.</p>
+
+
+<h3><b>Eucaine.</b></h3>
+
+<p>Eucaine was introduced as a substitute for cocaine, and, before the
+introduction of novocaine, was extensively used. It has a similar
+action to cocaine, and although it is less toxic, it is by no means
+free from danger unless it is used in very dilute solutions. It is a
+vaso-dilator, and must therefore be used in combination with adrenalin.
+It can be boiled without undergoing decomposition, and is practically
+non-irritant. It has been largely superseded by novocaine.</p>
+
+
+<h3><b>Quinine and Urea Hydrochloride.</b></h3>
+
+<p>The use of this drug for purposes of local anæsthesia is still in the
+experimental stage. It is made by adding urea to a solution of quinine
+in hydrochloric acid. The crystals are soluble in their own weight of
+water. For the production of local anæsthesia it is used in strengths
+of ·25 to 1 per cent. It is free from toxic effects, and its solutions
+can be sterilised by boiling.</p>
+
+<p>The striking feature about this drug is the extraordinary duration of
+the anæsthesia, this being from one to six days. It has therefore been
+used by Crile and other American surgeons to prevent pain during the
+first few days after operation. The great drawback to its use, however,
+is that it causes a persistent indurated condition of the tissues which
+interferes with primary union, and which is sometimes followed by
+actual sloughing. In addition, it is now established that its use has
+been followed by tetanus in several cases, and it is recommended that a
+dose of antitetanic serum should be given immediately before or after
+the injection of quinine.</p>
+
+<p>Although the action of this drug is of great interest, it cannot be
+recommended at present for ordinary purposes.</p>
+
+<p><span class="pagenum" id="Page_175">[175]</span></p>
+
+
+<h3><b>Adrenalin.</b></h3>
+
+<p>Adrenalin is obtained as an extract from the suprarenal glands of
+animals. It is a greyish white powder, slightly soluble in water, and
+readily so in weak acids. The usual preparation is a 1 in 1000 solution
+of adrenalin chloride in normal saline. It contains ·5 per cent. of
+chloroform as a preservative. The drawback to the animal extract is
+that the solution does not keep well, decomposition being indicated by
+a brownish colour. Of late a synthetic preparation has been introduced,
+which appears to have the same action, and which can be sterilised by
+boiling.</p>
+
+<p>The action of the drug is to cause marked vaso-constriction by direct
+action on the vessel walls. It has no analgesic action, and is used as
+an addition to solutions of anæsthetic drugs. The advantages of its use
+are that the action of the anæsthetic is concentrated and prolonged,
+owing to the delay in absorption, and that the field of operation is
+rendered practically bloodless. In large doses it may produce toxic
+symptoms in the form of palpitations and breathlessness, or even actual
+syncope, so that care is necessary in its use. For purposes of local
+anæsthesia, it is added to the solution of the anæsthetic drug in the
+strength of 3 drops to the ounce, and large injections of this dilute
+solution may be made without risk. At least twenty drops may be safely
+given.</p>
+
+
+<h3><b>Induction of Local Anæsthesia</b></h3>
+
+<p>Local anæsthesia may be induced by the use of anæsthetic drugs in three
+ways—(1) infiltration anæsthesia, (2) regional anæsthesia, and (3) by
+application to a mucous surface or to the surface of the eye.</p>
+
+<p><span class="smcap">Infiltration Anæsthesia.</span>—In this method anæsthesia is induced
+by injection of the drug directly into the tissues to be operated upon.
+This method acts by paralysing the sensory nerve-endings. Although
+the term anæsthesia is constantly used, it is, strictly speaking,
+an operative analgesia that is aimed at; it is a<span class="pagenum" id="Page_176">[176]</span> paralysis of the
+pain-conducting fibres, and not of those which conduct purely tactile
+sensations, the patient being often able to feel the contact of the
+fingers and instruments during the operation. True anæsthesia can be
+secured, but it is necessary to use considerably stronger solutions
+than those that are required for the production of analgesia.</p>
+
+<p><span class="smcap">Solution of the Drug.</span>—Novocaine is far superior to any other
+drug for infiltration anæsthesia. The strength for most purposes is ½
+per cent., though some operators find ¼ per cent. quite satisfactory.
+In specially sensitive parts, such as the nose, throat, or mouth, 1
+or even 2 per cent. solutions may be preferable. Sufficient sodium
+chloride should be added to prevent osmosis of the solution into the
+tissue cells. The most satisfactory preparation is:—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="cht">Novocaine</td>
+    <td class="right">0·25, 0·5, 1 or 2 (¼ to 2 percent.)</td>
+  </tr>
+
+  <tr>
+    <td class="cht">Normal salt solution (half strength)</td>
+    <td class="right">100·0 (·45 per cent. NaCl)</td>
+  </tr>
+</table>
+
+  <div class="figcenter" id="i_p176" style="max-width: 600px">
+     <img
+    class="p1"   
+    src="images/i_p176.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig</span>. 51. All-Metal Syringe for Infiltration Anæsthesia.</p>
+     </div>
+
+<p>Adrenalin is added to the solution in the proportion of 3 drops of 1 in
+1000 adrenalin chloride to the ounce, and as much as 6 ounces of this
+preparation may be safely given. The novocaine solution can be boiled
+before use, but the adrenalin must not be added until after boiling.</p>
+
+<p>For private practice it is sometimes convenient to procure the<span class="pagenum" id="Page_177">[177]</span>
+novocaine in tabloid form of definite strength combined with sodium
+chloride. These tabloids are added to the necessary amount of water,
+and the whole boiled. The adrenalin can then be added.</p>
+
+<p><span class="smcap">Choice of Syringe.</span>—The best form of syringe for infiltration
+anæsthesia is the all-metal syringe illustrated in Fig. 51. It ought
+to have a capacity of at least 10 c.c. The advantage of the all-metal
+syringe over glass syringes is that it can be safely sterilised by
+boiling, and does not get broken. Between the syringe and the needle is
+a metal segment which is curved so that the needle is set at an obtuse
+angle to the syringe. This renders the infiltration of the tissues at
+the proper depth much easier. The needles employed are the ordinary
+hypodermic needles which are sold in small tubes. The sizes which
+should be selected are 1 inch, and 3 or 3½ inches. The needle fits into
+a hole in a small metal mount, which screws on to the intermediate
+metal portion. This section also is attached to the syringe by a screw,
+and these screw attachments have the advantage of rendering leakage
+impossible.</p>
+
+<p>Failing the syringe described, a 10 c.c. Record syringe will be found
+to be quite efficient, if suitable needles can be obtained. The
+syringe, needles, and glass measure for the solution should be boiled
+in plain water or normal saline, as soda interferes with the action of
+the drug.</p>
+
+<p><span class="smcap">Technique of Injection.</span>—The needle is introduced into the
+subcutaneous tissue, and pushed on slowly to its full length, the
+fluid being injected as the needle advances. The needle is then partly
+withdrawn, and pushed in in a different direction so as to infiltrate a
+fresh area. This procedure is repeated, and as wide an area as possible
+infiltrated from the one puncture. The needle can then be completely
+withdrawn and introduced at a fresh point which has already been
+rendered analgesic. The deeper tissues can nearly always be infiltrated
+from the surface, but if large blood-vessels traverse the region to be
+infiltrated, it may be necessary to<span class="pagenum" id="Page_178">[178]</span> defer the deeper injection until
+these have been exposed. It is wise to infiltrate wide of the intended
+line of the incision, since it is not possible to anticipate with
+certainty the extent of an operation until it has been commenced. The
+secret of successful anæsthesia is to employ plenty of the solution,
+and make the injection thorough.</p>
+
+<p>The skin over the area becomes blanched within a few minutes of the
+injection owing to the action of the adrenalin. Anæsthesia is not
+usually complete until ten minutes have elapsed, and the operation
+should not be commenced until it has been made certain by suitable
+tests that the anæsthesia is complete. The duration of the anæsthesia
+is usually at least an hour and a half.</p>
+
+<p>It will be seen that the injection in the manner described above is
+entirely subcutaneous, the pain-conducting nerves from the skin being
+caught up by the drug as they traverse the superficial fascia in the
+area infiltrated. This method usually gives complete satisfaction,
+but some surgeons advise that the infiltration should be commenced
+with an <i>intra-dermal</i> injection so as to reduce the pain of the
+needle punctures to a minimum. A fine needle is employed, the prick
+of which is practically painless. If the skin at the selected point
+is pinched up between the finger and thumb, and held firmly, this
+lessens its sensibility. The needle is advanced beneath the epidermis
+with a quick but light thrust. The injection into the substance of the
+skin causes a distinct wheal, which stands out from its surroundings
+like an urticarial wheal. From this starting-point a long needle can
+be introduced into the deeper tissues without pain. The intra-dermal
+injection may be carried along the whole length of the area to be
+infiltrated, each fresh puncture being made in the margin of the
+wheal-like area already anæsthetised.</p>
+
+<p><span class="smcap">Precautions.</span>—The most careful asepsis is essential
+throughout. Infiltration with novocaine causes no interference with the
+healing<span class="pagenum" id="Page_179">[179]</span> of the wound, and although cases of sloughing of the tissues
+have been reported after its use, these are almost certainly due to
+infection of the wound. Care must be exercised also to avoid injecting
+the drug into a vein. When this accident takes place, the drug is
+carried at once into the general circulation, and may reach the higher
+nerve centres in such quantity as to produce serious toxic results. The
+use of adrenalin calls for special care and thoroughness in securing
+all bleeding-points, as, after the effect of the adrenalin passes off,
+even a slight ooze may increase and give rise to a hæmatoma which may
+jeopardise the healing of the wound.</p>
+
+
+<h3><b>Regional Anæsthesia.</b></h3>
+
+<p>In this method of producing anæsthesia, the sensory nerve paths are
+blocked by injecting the anæsthetic drug into, or around, a nerve
+trunk. By this procedure complete anæsthesia is produced in the area of
+distribution of the nerve, and the effect corresponds to a temporary
+physiological section of the nerve trunk. A temporary motor paralysis
+is also produced in a mixed nerve.</p>
+
+<p><span class="smcap">Technique.</span>—The solution of the drug must be stronger than
+that employed for infiltration anæsthesia. A 2 per cent. solution of
+novocaine in half-strength normal saline with the addition of adrenalin
+is employed. The injection may be paraneural or intraneural.</p>
+
+<p>A <i>paraneural</i> injection is made by passing a needle through
+the tissues to the known position of a nerve trunk and injecting the
+anæsthetic around it. The solution gradually diffuses into the nerve
+tissue, and anæsthesia of the nerve is produced. This method is open
+to the objection that unless the anæsthetic is accurately placed, no
+anæsthesia will result, and that in the case of certain nerves there is
+considerable risk of making the injection into a vein. The latter risk
+can be avoided by using a glassbarrelled<span class="pagenum" id="Page_180">[180]</span> syringe and applying a little
+suction before the injection is made; if a vein has been pierced, blood
+will enter the syringe.</p>
+
+<p>The <i>intraneural</i> method is more accurate but requires the
+expenditure of considerable additional time and trouble, and is only
+employed where other methods of anæsthesia are not feasible. The tissue
+over the nerve having been infiltrated, the nerve is exposed by open
+dissection. It must not be pinched by forceps or other instruments,
+as such manipulations cause severe pain referred to its peripheral
+distribution. The injection should be made with the nerve lying in its
+bed by inserting a fine needle in the long axis of the nerve, first
+into the sheath, which is infiltrated, and then into the nerve itself.
+The infiltration of the nerve is continued until it presents a fusiform
+swelling and this may require from 5 to 15 minims of the solution.
+Complete anæsthesia of its entire distribution usually results in from
+five to ten minutes.</p>
+
+<p>A third method of inducing regional anæsthesia—first recommended by
+Hackenbruch—which is worth mention, is by the production of a ring
+of infiltration around a peripheral part, such as a finger, or around
+and underneath a tumour. By this means the nerve fibres are caught up
+by the anæsthetic and their conductivity interrupted as they enter the
+area to be operated upon. In dealing with such conditions as a large
+lipoma, or an umbilical hernia, it may be possible to avoid the use of
+an excessive amount of anæsthetic solution by employing this method.</p>
+
+
+<h3><b>Methods of Application of Infiltration and Regional Anæsthesia.</b></h3>
+
+<p>It is sometimes stated that local anæsthesia should be limited to
+small and superficial operations, but with a knowledge of anatomy and
+of the correct technique, there are few operations which the surgeon
+cannot undertake with this form of anæsthesia. If we remember that the
+mortality from the anæsthetic is practically nil, it is obvious that it
+is often the duty of the operator to<span class="pagenum" id="Page_181">[181]</span> give the patient the choice of
+local anæsthesia. In urgent conditions in which the administration of a
+general anæsthetic would be attended with great danger, it is often a
+life-saving measure. Either infiltration or regional anæsthesia may be
+used alone; in some cases it is convenient to combine the two methods.</p>
+
+
+<h3><b>Operations on the Upper Extremity.</b></h3>
+
+<p>Regional anæsthesia is sometimes employed in operations on the upper
+extremity in conditions, such as diabetic gangrene or advanced cardiac
+disease, where a general anæsthetic is contra-indicated. In similar
+conditions in the lower extremity, spinal anæsthesia is usually
+preferred, though it is quite possible to anæsthetise the lower limb
+by blocking the sciatic, femoral, and lateral cutaneous nerves with a
+local anæsthetic. Crile lays great stress on the blocking of nerves
+with a local anæsthetic during operations on the limbs as a means of
+preventing shock, even where a general anæsthetic is being employed.
+The effect of the local anæsthetic is to prevent the impulses which
+produce shock from passing up to the higher centres. Only those methods
+which are applied to the upper extremity need special description.</p>
+
+<p><span class="smcap">Anæsthesia of the Whole Arm.</span>—The nerves of the upper
+extremity are all derived from the brachial plexus except the
+intercosto-brachial. This nerve, which is the lateral cutaneous
+branch of the second intercostal, crosses the axilla and pierces the
+deep fascia on the medial side of the arm. It supplies the skin on
+the dorsal part of the medial aspect of the upper arm. The lateral
+cutaneous branch of the third intercostal nerve sometimes crosses
+the axilla also, and reaches the medial side of the arm. Injection
+of the brachial plexus produces complete analgesia of the shoulder
+and entire arm, and is particularly suited to high amputations
+and disarticulations at the shoulder. If the area supplied by the
+intercosto-brachial is encroached upon, this can be anæsthetised<span class="pagenum" id="Page_182">[182]</span> by
+infiltration with a few drams of solution injected subcutaneously along
+the floor of the axilla from its lateral and posterior borders.</p>
+
+<p><span class="smcap">Method.</span>—The injection may be intraneural or paraneural. The
+intraneural is made after exposing the plexus by an incision under
+infiltration anæsthesia from the junction of the middle and lower
+thirds of the sterno-mastoid to the union of the middle and lateral
+thirds of the clavicle. It is found lying on the scalenus medius and
+each of its branches is separately injected with a few drops of 5 per
+cent. solution of novocaine containing a few drops of adrenalin to the
+ounce.</p>
+
+<p>The paraneural injection is less satisfactory, since the nerves
+are too large to be readily penetrated in effective quantities by
+the anæsthetic solution, and since there are numerous veins in the
+neighbourhood into which the solution may be accidentally injected with
+dangerous results.</p>
+
+<p>The injection is usually made above the clavicle. In this region the
+plexus lies mainly above and to the lateral side of the third part
+of the subclavian artery, the lowest trunk lying directly behind the
+vessel as it rests on the first rib. The position of the artery is
+first localised with the finger by its pulsations, and the skin and
+subcutaneous tissue infiltrated immediately above the mid-point of
+the clavicle. From this point a long fine needle, unattached to the
+syringe, is passed downwards, backwards, and medially in the direction
+of the second or third thoracic spine. The distance to which the
+needle penetrates varies from 2 to 4 c.m. When the plexus is reached a
+slight radiating pain is felt down the distribution of the radial or
+median nerve. At this point the needle is held stationary, the syringe
+attached, and the injection made. The reason for not attaching the
+syringe earlier is that should the artery be entered, blood will flow.
+This accident is of little consequence, the needle being withdrawn
+slightly and introduced a little more laterally. About 10 c.c. of a
+2 per cent.<span class="pagenum" id="Page_183">[183]</span> solution of novocaine and adrenalin is injected; the
+needle is then slightly withdrawn and a further 10 c.c. injected in the
+neighbourhood. Anæsthesia occurs in from three to fifteen minutes.</p>
+
+  <div class="figcenter" id="i_p183" style="max-width: 350px">
+     <img
+    class="p1"   
+    src="images/i_p183.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig. 52.</span>—Point at which the needle is
+introduced in paraneural injection of brachial plexus.</p>
+     </div>
+
+<p>The individual nerves of the upper limb can be readily injected.
+The <i>median</i> can be exposed at the bend of the elbow for an
+intraneural injection, or a needle may be passed under the tendon
+of the palmaris longus at the wrist for a paraneural injection.
+The <i>ulnar</i> can be easily reached as it lies on the posterior
+aspect of the medial epicondyle of the humerus for a paraneural or
+intraneural injection. The <i>superficial radial</i> can be reached for
+a paraneural<span class="pagenum" id="Page_184">[184]</span> injection about two inches above the wrist to the lateral
+side of the tendon of the brachio-radialis (supinator longus). The
+injection is made into the deep fascia, and carried across the lateral
+border of the forearm for about an inch, to ensure reaching all the
+branches of the nerve.</p>
+
+<p>The <i>medial antibrachial</i> (internal) <i>cutaneous</i> can be
+blocked on the front of elbow by a paraneural injection about half
+an inch medial to the biceps tendon, and the <i>lateral antibrachial
+cutaneous</i> (musculo-cutaneous) at a corresponding point on the other
+side of the tendon.</p>
+
+<p><span class="smcap">Anæsthesia of the Arm below the Elbow.</span>—In operations
+below the elbow, in conditions in which a general anæsthetic is not
+permissible, as in diabetes, nephritis or advanced cardiac disease, a
+full anæsthesia can be obtained by intraneural injection of the median,
+ulnar, and radial (musculo-spiral) nerves, combined with paraneural
+injection of the medial and lateral antibrachial cutaneous. The
+median and radial are each exposed by an incision under infiltration
+anæsthesia, the radial being exposed in the groove between the
+brachialis and brachio-radialis. The infiltration to expose the median
+nerve usually blocks the anterior branch of the medial antibrachial
+cutaneous. To make certain that the posterior branch is also
+anæsthetised, it is advisable to inject a little anæsthetic solution
+over the front of the medial epicondyle. The intraneural injection into
+the ulnar nerve can often be made without exposing it.</p>
+
+<p><span class="smcap">Anæsthesia of Finger.</span>—The paraneural method applied to the
+digital nerves at the root of the finger gives perfect results. A
+circle of anæsthetic solution is first injected round the root of the
+finger. The needle is then passed through the infiltrated skin on each
+side of the finger, and a few drops of ½ per cent. novocaine solution
+injected around the nerves. Complete anæsthesia of the finger results
+in a few minutes.</p>
+
+<p><span class="pagenum" id="Page_185">[185]</span></p>
+
+<p><span class="smcap">In the Lower Limb</span> injection of individual nerves is rarely
+employed, as anæsthesia is easily obtained by the method of spinal
+analgesia. The <i>lateral cutaneous</i> can be injected as it lies
+immediately medial to the anterior superior iliac spine emerging from
+under cover of the inguinal ligament. This procedure may be useful in
+obtaining skin grafts, the grafts being taken from the antero-lateral
+aspect of the thigh. Amputations in the middle third of the thigh have
+been performed by injecting the sciatic, the posterior cutaneous (small
+sciatic), the femoral (anterior crural), and the lateral cutaneous at
+the root of the limb. The obturator nerve is difficult to find and
+anæsthetise in such cases. Operations below the knee can be painlessly
+performed by this method of anæsthesia.</p>
+
+
+<h3><b>Operations on the Neck.</b></h3>
+
+<p><span class="smcap">Tracheotomy.</span>—This operation is conveniently and safely
+performed under infiltration anæsthesia. The anæsthetic solution is
+injected in the usual way in the line of the incision down to the
+trachea but not into it, as the trachea itself is insensitive to pain.</p>
+
+<p><span class="smcap">Goitre.</span>—A parenchymatous or adenomatous goitre can be readily
+removed under local anæsthesia, though the administration of ether by
+intra-tracheal insufflation is usually to be preferred. The principal
+nerve supply to the field of operation is derived from the cervical
+plexus, whose branches become superficial about the middle of the
+posterior border of the sterno-mastoid. An intradermal injection may
+be made first at this point, and a longer needle then passed down
+to the posterior border of the muscle, and an area of infiltration
+produced. From this point the needle is directed first upwards and
+then downwards round the margin of the goitre so as to produce a zone
+of infiltration. The same procedure may be repeated on the opposite
+side, so that the whole gland is surrounded with a zone of infiltration
+with a special depot of solution around the branches of the cervical
+plexus. Where only one lobe is involved, it is sufficient to carry the
+injection down<span class="pagenum" id="Page_186">[186]</span> in the middle line after one side has been encircled.
+When the sheath has been incised and the surface of the gland exposed,
+the isthmus is infiltrated and divided. The affected half of the gland
+is then rolled outwards, and the attachments between the posterior
+aspect of the gland and the larynx and trachea are infiltrated, special
+attention being paid to the upper pole. The rest of the operation can
+then be carried out painlessly.</p>
+
+<p><span class="smcap">Exophthalmic Goitre</span> may also be operated upon under local
+anæsthesia after a preliminary hypodermic injection of morphia and
+scopolamin, though many operators prefer a general anæsthetic on
+account of the nervous state of the patient. In bad cases a procedure
+which is often of great value is ligature of the superior thyroid
+artery on both sides under local anæsthesia. After ligature of the
+vessels a colloid degeneration takes place in the gland, and the
+symptoms of hyperthyroidism subside. After a delay of two or three
+months it may be possible to carry out the radical operation with
+little or no danger. The incision is two and a half inches in length,
+and crosses transversely the central part of the thyroid cartilage.
+The line of the incision is infiltrated with novocain solution in the
+ordinary way, and both superior thyroid arteries exposed and ligatured.</p>
+
+
+<h3><b>Operations on the Thorax.</b></h3>
+
+<p>The greater part of the wall of the thorax is supplied by the
+intercostal nerves. In front the supraclavicular nerves come down
+as far as the second intercostal space or sometimes as far as the
+nipple, and the lateral and medial anterior thoracic nerves supply
+the pectoral muscles, sending a few twigs to the overlying skin. The
+long thoracic nerve extends down the side of the chest, supplying the
+serratus anterior. The intercostal nerves can be blocked in the region
+of the angles of the ribs and the supraclavicular by carrying a line of
+infiltration along the clavicle. The anterior thoracic can be blocked
+by deeper injections. In<span class="pagenum" id="Page_187">[187]</span> this way the greater part of the chest wall
+and the pleura can be anæsthetised.</p>
+
+<p><span class="smcap">Acute Empyema.</span>—This operation should always be performed
+under local anæsthesia. Exhaustion from septic absorption and from
+the antecedent pneumonia or other disease, with the dyspnœa from
+the pressure of the pus on the lung may render a general anæsthetic
+highly dangerous. The method of producing local anæsthesia is simple
+and easily carried out. A point is selected on the rib which is to
+be resected a short distance behind the line of the incision and an
+intra-dermal injection made with a fine needle. A long needle is then
+substituted and passed down to the upper border of the rib until it
+reaches the plane between the external and internal intercostal muscle,
+the injection being continued lightly as it advances. When the desired
+point is reached one or two drams of the solution are injected. The
+needle is then slightly withdrawn and passed to the lower border of
+the rib to reach the same plane and the same procedure carried out.
+The infiltration is then carried along the line of the incision or it
+may be made to pass obliquely upwards to the rib above and obliquely
+downwards to the rib below so as to catch up the nerves coming from
+behind into the area of operation. The anæsthesia of soft parts, bone,
+and pleura is perfect after the above injection.</p>
+
+
+<h3><b>Operations on the Abdomen.</b></h3>
+
+<p>The anterior abdominal wall, including the anterior parietal
+peritoneum, is supplied by the lower six intercostal nerves, the last
+thoracic nerve, and the ilio-hypogastric and ilio-inguinal nerves
+from the first lumbar. It is a very interesting and important fact
+that, although the parietal peritoneum is exceedingly sensitive to
+touch and pain, the visceral peritoneum and the viscera themselves
+are insensitive. When operations are performed under local anæsthesia
+of the abdominal wall, the<span class="pagenum" id="Page_188">[188]</span> viscera can be freely handled or incised
+without the patient experiencing the slightest discomfort, provided
+that the parietal peritoneum is not put upon the stretch by traction
+on the mesentery or other peritoneal attachment. Thus the colon
+can be opened twenty-four or forty-eight hours after being brought
+outside the abdominal wall without any anæsthetic in the operation of
+colostomy. Local anæsthesia is therefore well adapted to cases in which
+a small amount of manipulation of the viscera is required, and where a
+general anæsthetic would be dangerous, as in grave cases of intestinal
+obstruction and in cases of carcinoma of the œsophagus with weakness
+and loss of flesh from starvation.</p>
+
+<p><span class="smcap">Gastrostomy.</span>—This operation is commonly performed under
+local anæsthesia and may be taken as an illustration of the procedure
+employed. The incision is made through the middle of the left rectus
+and is about two and a half or three inches long, beginning about an
+inch below the costal margin. An intradermal wheal is established at
+the middle of the proposed incision. A long needle is entered at this
+point and passed first upwards and then downwards in the line of the
+incision, infiltrating the subcutaneous fat as it goes. The needle is
+then passed in through the anterior wall of the rectus sheath, this
+being easily recognised as a plane of decided resistance. The needle
+is advanced a little inside the sheath, the injection being continued
+as it advances. The same procedure is repeated at various points along
+the line of the incision. The extra-peritoneal fat may be infiltrated
+in the same way, the posterior wall of the sheath being identified
+as a deeper plane of resistance and gently pierced. This step may be
+deferred until the posterior wall of the sheath has been exposed.
+The infiltration may be completed by forming a line of intradermal
+infiltration along the line of incision, though this last step can
+often be omitted.</p>
+
+<p>The abdomen can then be opened painlessly. The only step in<span class="pagenum" id="Page_189">[189]</span> the
+operation which may cause a little discomfort is the traction which may
+be necessary to bring the shrunken stomach down from under cover of the
+ribs. The incision into the stomach is quite painless.</p>
+
+<p><span class="smcap">Gastro-enterostomy</span> can be performed under local anæsthesia,
+the only special step required being infiltration of the meso-colon
+before it is perforated.</p>
+
+<p><span class="smcap">Appendicectomy</span> is not suitable, as a rule, for local
+anæsthesia. If the cæcum is fixed or the appendix bound down by
+adhesions, the traction necessary to bring the appendix to the surface
+causes considerable pain.</p>
+
+<p>In <span class="smcap">Acute Obstruction</span>, when the procedure of enterostomy has
+been decided upon owing to the gravity of the patient’s condition,
+local anæsthesia is often of great value. The abdominal wall is
+infiltrated in the manner described, and a distended loop of bowel
+brought to the surface and sutured to the parietal peritoneum. A Paul’s
+tube can then be introduced.</p>
+
+<p><span class="smcap">Inguinal Hernia.</span> Local anæsthesia is specially suited to cases
+of strangulated hernia, but it may be employed in the ordinary case. It
+should be pointed out that spinal anæsthesia gives equally good results
+and is less troublesome to carry out.</p>
+
+<p>The injection is commenced with a fine needle a little beyond the
+lateral end of the proposed incision. An intradermal wheal is produced
+at this point, a long needle introduced into the subcutaneous tissue,
+and about half-an-ounce of anæsthetic solution injected in this
+position. The needle is then passed downwards and medially, and the
+subcutaneous fat infiltrated in the line of the incision. The needle
+is then partly withdrawn and again advanced until it reaches the
+resistance of the aponeurosis of the external oblique. This is gently
+pierced and about half-an-ounce of solution injected underneath so as
+to block the ilio-hypogastric and ilio-inguinal nerves. In most cases
+this is all that is necessary.<span class="pagenum" id="Page_190">[190]</span> As additional precautions the line of
+incision may be infiltrated intradermally, and an injection may be made
+around the neck of the sac after it is exposed.</p>
+
+<p><span class="smcap">Femoral Hernia.</span>—A femoral hernia may be anæsthetised by
+infiltration along the line of the incision, or by injecting around
+the circumference of the hernia after the method of Hackenbruch. After
+the sac has been exposed and defined, it is necessary to inject some
+novocaine solution around the neck, care being taken to avoid the
+femoral vein which lies on the lateral side.</p>
+
+<p><span class="smcap">Umbilical Hernia.</span>—Local anæsthesia is sometimes of
+great value in dealing with umbilical hernia, especially if it is
+strangulated, in stout patients who are bad subjects for a general
+anæsthetic. The injection is best made around the circumference of the
+hernia. Several intradermal injections are made at points around the
+swelling, and through these the long needle can be introduced and the
+deeper tissues infiltrated. If the muscles are fairly well defined
+and can be felt, they may be infiltrated at the commencement, but
+it may be advisable in fat subjects to inject only the subcutaneous
+tissues to begin with, and to delay the injection of the muscles and
+extra-peritoneal fat until the sac has been opened and a protecting
+finger can be introduced to guard the intestines. Omental adhesions
+can be divided without causing pain. If the intestines are extensively
+adherent to the sac it is better to infiltrate the points of adhesion,
+as extensive manipulation may cause cramp-like pains.</p>
+
+<p>After the circumferential injection has been made in these cases, it is
+best to wait for ten or fifteen minutes before making the incision in
+order to allow the anæsthetic solution to diffuse.</p>
+
+<p><span class="smcap">Suprapubic Cystotomy.</span>—In operations for drainage of
+the bladder local anæsthesia is highly successful. The skin and
+subcutaneous tissues are infiltrated in the line of the incision.
+The needle is then carried between or through the recti muscles and<span class="pagenum" id="Page_191">[191]</span>
+several drams injected into the layer of fat in front of the bladder.
+It is unnecessary to inject the wall of the bladder itself.</p>
+
+<p><span class="smcap">Hæmorrhoids.</span>—In patients in whom there is some
+contra-indication to the use of a general anæsthetic the removal of
+hæmorrhoids can be carried out quite safely and painlessly under local
+anæsthesia. A circumferential injection is first carried out round the
+muco-cutaneous junction. It is best to start the infiltration about an
+inch out from the anus as the skin immediately around the anal orifice
+is extremely sensitive. The infiltration is made subcutaneously,
+and each re-insertion of the needle is made just short of where the
+previous injection stopped. When the circumferential injection has been
+completed, a finger is passed into the rectum, and the long needle
+introduced through the anæsthetised area, injecting as it advances, to
+a depth of about 2½ inches, keeping just outside the sphincters. Four
+such injections are made, one on each side of the bowel, one in front
+and one behind, from 5 to 10 c.c. being injected in each position.</p>
+
+<p>Anæsthesia results almost immediately and the anal canal can be readily
+dilated.</p>
+
+<p><span class="smcap">The Tongue.</span>—For the Whitehead operation of removal of
+one half of the tongue, complete anæsthesia can be obtained by the
+infiltration method. A long needle is introduced at the tip of the
+tongue, and the injection carried in the middle line to a point behind
+the tumour. The mucous membrane of the floor of the mouth and the
+glosso-palatine fold are infiltrated, and a last injection made across
+the affected half of the tongue well behind the tumour.</p>
+
+<p>The tongue can be anæsthetised also by blocking the lingual nerve
+with a paraneural injection. The nerve lies under the mucous membrane
+of the mouth opposite the last molar tooth. If the tongue is drawn
+well over to the opposite side, the nerve can be felt and the
+injection made around it. The only drawback<span class="pagenum" id="Page_192">[192]</span> to this method is that
+it does not anæsthetise the posterior third, which is supplied by the
+glosso-pharyngeal nerve.</p>
+
+<p><span class="smcap">Operations on the Skull and Brain</span> can be readily performed
+by infiltration of the scalp. In the later stages of the recent
+war, a large proportion of operations on the skull and brain were
+performed under local anæsthesia. The brain itself is insensitive to
+touch and painful stimuli, and infiltration of the scalp is all that
+is necessary. A 1 per cent. solution of novocaine with adrenalin has
+been commonly employed, and is injected into the subaponeurotic space
+so as to surround the field of operation with a wall of anæsthetic
+solution—the method of Hackenbruch. The advantages are that hæmorrhage
+is reduced to a minimum, and the head can be conveniently and safely
+elevated and the intra-cranial tension thus reduced.</p>
+
+
+<h3><b>Analgesia from the Application of Cocaine to the Eye or to a Mucous
+Surface.</b></h3>
+
+<p><span class="smcap">For Operations on the Eye.</span>—Analgesia is obtained by the
+instillation of a few drops of a 4 per cent. solution into the
+conjunctival sac. This is repeated two or three times, and analgesia
+is obtained in five or ten minutes. It may be necessary to repeat the
+instillation during the course of the operation.</p>
+
+<p><span class="smcap">For Operations on the Nose, Pharynx, or Larynx</span> cocaine is
+commonly used. A 5 or 10 per cent. solution is employed and is merely
+painted on the surface. Care must be taken that such strong solutions
+are not swallowed.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_193">[193]</span></p>
+
+<h2>CHAPTER XXI.<br>
+<span class="subhed"><b>SPINAL ANÆSTHESIA.</b></span></h2></div>
+
+<p>Spinal Anæsthesia or <i>Analgesia</i>, consists in the production of
+analgesia in the lower extremities and in the lower part of the trunk
+by the injection into the subarachnoid space of an anæsthetic drug
+which blocks the spinal nerves as they enter and leave the spinal
+cord. The cord ends at the lower border of the first lumbar vertebra
+and the subarachnoid space at the second sacral vertebra so that there
+is a considerable area into which the injection may be made without
+risk of injury to the cord. It is, in reality, a special variety of
+regional analgesia, the anæsthetic being injected into that part of
+the subarachnoid space which is occupied by the cauda equina. The
+subarachnoid space of the medulla spinalis contains the cerebro-spinal
+fluid and communicates above with the subarachnoid space inside the
+skull and through the foramen of Magendie, with the ventricular system
+of the brain. The subdural space of the medulla spinalis is merely a
+capillary interval. At the upper end of the cauda equina the nerve
+trunks of the two sides are separated by a median interval—containing
+only the filum terminale—which has been termed the cysterna
+terminalis. It is into this median space that the injection is made, in
+order to avoid wounding the nerve trunks and to procure equal diffusion
+of the anæsthetic to both sides of the middle line. If the injection is
+made among the nerve trunks on one side, a unilateral anæsthesia may
+result, the drug being prevented from diffusing freely to the other
+side by the presence of the numerous nerves.</p>
+
+<p><span class="pagenum" id="Page_194">[194]</span></p>
+
+<p>The ligamentum denticulatum forms an imperfect scalloped septum between
+the posterior and the anterior nerve roots, passing from the surface
+of the cord to the dura mater. The presence of this septum probably
+explains the fact that the motor nerves are not affected with the same
+constancy and to the same extent as the sensory roots.</p>
+
+
+<h3><b>Technique.</b></h3>
+
+<p>The drug which is most commonly employed in the Edinburgh school is
+Tropacocaine, and the results of its use with proper technique are
+eminently satisfactory. The dose of the drug for most purposes is ·07
+gramme. Smaller doses are sometimes used but the larger dose gives
+more constant anæsthesia and appears to be well within the limits
+of safety. The dose is dissolved in 1 c.cm. of distilled water and
+sufficient sodium chloride added to make a solution isotonic with the
+cerebro-spinal fluid. A convenient method of obtaining the drug is
+in glass ampoules, each ampoule containing one dose, which has been
+carefully sterilised.</p>
+
+  <div class="figcenter" id="i_p194" style="max-width: 590px">
+     <img
+    class="p1"   
+    src="images/i_p194.jpg"
+     alt="">
+     <p class="p0 center smaller"><span class="smcap">Fig</span>. 53.—Needle and syringe for spinal
+analgesia. Note the short oblique character of the point of the needle.</p>
+     </div>
+
+<p>The syringe and needle employed are illustrated in Fig. 53.</p>
+
+<p>The point of the needle must be sharp but short. If a needle with a
+long slender point is employed, only part of the point may enter the
+membranes; a free flow of cerebro-spinal fluid may then take place,
+but when the injection is made part of the anæsthetic solution escapes
+outside the membranes. The needle<span class="pagenum" id="Page_195">[195]</span> should he 3½ to 4 inches long and 1
+m.m. in diameter. A stylet fits inside the needle and prevents it from
+becoming blocked during the introduction. To prevent the possibility
+of rusting, both needle and stylet should consist of hard nickel. The
+barrel of the syringe must consist of glass so that the appearance
+of the cerebro-spinal fluid can be seen. The Record type is very
+satisfactory. The syringe usually supplied for spinal analgesia has
+a capacity of 2 or 3 c.cm., but one holding 10 c.cm. is more useful.
+Syringe and needle must be carefully sterilised by boiling in plain
+water; any trace of soda causes decomposition of the drug. The ampoule
+containing the tropococaine is sterilised in a strong antiseptic
+solution so as to avoid the possibility of contamination of the hands
+when the drug is being transferred to the syringe.</p>
+
+<p><i>Method of Injection.</i>—The patient should be given a hypodermic
+injection of ⅛ gr. of morphine and ¹⁄₁₅₀ gr. of scopolamine an hour
+before the operation. There are a number of minor variations in the
+method of making the spinal injection, but limitations of space forbid
+a discussion of theoretical questions and of the relative merits of
+the different procedures. Only one method, which has been found safe
+and reliable, will be considered here. The injection is made in the
+space between the third and fourth lumbar spines, the objective being
+the mid-line of the subarachnoid space between the two divisions of
+the cauda equina. The position of the patient is such that the spaces
+between the lumbar spines are opened up as widely as possible. The
+most convenient plan is to have the patient sitting on the table with
+the head and shoulders bent well forward (<i>see</i> Fig. <a href="#i_p196">54</a>.) If the
+patient is unable to sit up, the injection may be made with him lying
+on his side, with the knees drawn up and the shoulders bent forward.</p>
+
+  <div class="figcenter" id="i_p196" style="max-width: 420px">
+     <img
+    class="p1"   
+    src="images/i_p196.jpg"
+     alt="">
+     <p class="p0 hangingindent smaller"><span class="smcap">Fig</span>. 54. Position for the injection. The cross
+indicates the point at which the lumbar puncture is made—about
+half an inch from the median plane and in the space between the
+third and fourth lumbar spines.</p>
+     </div>
+
+<p>The skin of the back is carefully sterilised; painting with tincture of
+iodine serves admirably. The ampoule containing the<span class="pagenum" id="Page_196">[196]</span> tropacocaine is
+opened, and the drug sucked into the syringe through a spare cannula.
+The loaded syringe is then placed on a sterile towel at the back of the
+patient. With a little practice there is no difficulty in making the
+lumbar puncture. The fourth lumbar spine is located by noting the level
+of the highest point on the iliac crest—this may be indicated by an
+assistant. A line joining the highest points on the two iliac crests
+will pass through the tip of the fourth lumbar spine. When this process
+has been carefully identified, the needle is introduced half-an-inch to
+one side of the median plane and midway between the third and fourth
+spine. Some surgeons prefer to go in exactly in the middle line to make
+sure of entering the middle of the subarachnoid space, but in<span class="pagenum" id="Page_197">[197]</span> this
+position the tough supra-spinous and interspinous ligaments are met
+with, and to avoid the resistance of these it is best to keep a short
+distance out from the median plane. By carefully noting the direction
+of the needle, the cysterna terminalis can always be entered. The
+needle is passed forwards, very slightly upwards, and slightly medially
+so as to hit off the centre of the subarachnoid space. As the needle
+passes through the ligamentum flavum, there is a sudden diminution of
+resistance and immediately afterwards the point of the needle lies in
+the subarachnoid space. The passage of the needle through the membranes
+is sometimes accompanied by a slight pricking pain.</p>
+
+<p>The stylet is withdrawn at this stage and the cerebro-spinal fluid
+usually trickles out drop by drop. The syringe is picked up, carefully
+emptied of air bubbles, and fitted on to the needle. The piston is
+withdrawn until the syringe is filled with cerebro-spinal fluid, which
+mixes freely with the anæsthetic solution, and the contents then
+slowly injected. The 10 c.cm. syringe is to be preferred for this
+purpose as it is essential to mix the tropacocaine thoroughly with the
+cerebro-spinal fluid. If the smaller syringe is used, it should be
+refilled with cerebro-spinal fluid and emptied a second time so as to
+ensure thorough diffusion of the drug. The needle is then withdrawn and
+the puncture sealed with collodion.</p>
+
+<p>The injection should never be made until a free flow of cerebro-spinal
+fluid is obtained, since this is the only certain indication that the
+needle has entered the subarachnoid space. If failure is met with in
+the space between the third and fourth spines, the interspinous space
+above or below should be tried.</p>
+
+<p>After the injection has been completed the patient is placed flat on
+his back and then lowered into the Trendelenburg position. Analgesia
+appears first in the scrotum and perineum, extends down the medial
+side of the leg to the foot, then appears on the front of the leg, and
+travels up to the groin and the lower part of the abdomen. The progress
+of the analgesia is tested from<span class="pagenum" id="Page_198">[198]</span> time to time by lightly pinching
+or pricking the skin, the patient’s eyes being screened. When the
+analgesia reaches the level of the nipples, the patient is raised into
+the horizontal position and the the operation may be commenced. Some
+surgeons object to the lowering of the head as rendering paralysis of
+the respiratory centre from upward diffusion of the drug more likely.
+If tropacocaine is used in the dosage indicated and the table elevated
+when the anæsthesia reaches the nipple line, there seems to be little
+risk of this complication. If analgesia is only desired in the lower
+extremity, the lowering of the table may be omitted; but if a good
+anæsthesia is desired above the level of the groin, it should always be
+carried out.</p>
+
+<p>Analgesia is complete in five or ten minutes as a rule. The duration
+varies from three-quarters of an hour to an hour and a half. If a
+preliminary hypodermic injection of morphine and scopolamine has been
+given, the patient lies quietly and patiently until the operation is
+completed. In some cases the patient actually drops off to sleep from
+the effects of the morphine. It is not uncommon to observe a temporary
+nausea and faintness about fifteen or twenty minutes after the
+injection has been made, and it is good practice to give the patient a
+little brandy and water at this stage.</p>
+
+
+<h3><b>Complications and After-Effects.</b></h3>
+
+<p>A great deal has been written in the past with regard to unpleasant
+results of spinal analgesia, but most of these would appear to have
+been the result of faulty technique or of the use of an impure or
+irritating drug. When tropacocaine is used in the manner described, the
+usual result is that, except for occasional nausea and faintness at
+the commencement, the patient has a comfortable, painless operation,
+and a recovery which is unmarred by the sickness and other distressing
+symptoms which are so common after general anæsthesia.</p>
+
+<p><i>Deaths</i> have been recorded, and these have been ascribed to<span class="pagenum" id="Page_199">[199]</span>
+the drug having travelled too high and brought about paralysis of
+the respiratory centre in the medulla oblongata. Too much importance
+has probably been ascribed to these fatal cases. They have been most
+common in patients greatly enfeebled by shock, old age, or debilitating
+illness, who are liable to die during the operation whatever anæsthetic
+is used. Thousands of cases have been recorded without a death, and
+in the hands of surgeons of skill and judgment fatal cases are almost
+unknown.</p>
+
+<p>An occasional complication is severe <i>headache</i> which may
+persist for a week or longer. Other complications are all exceedingly
+rare; paralysis of the lateral rectus muscle of the eyeball or of
+other ocular muscles has been recorded, and is probably due to toxic
+bye-products which are the result of impurity of the drug. Persistent
+nausea and paralysis of the bladder and rectum and even of the lower
+extremities have also been recorded, but are to be regarded as the
+greatest rareties, and probably due to impurity of the anæsthetic.</p>
+
+
+<h3><b>Indications.</b></h3>
+
+<p>Spinal analgesia may be used for any operation at or below the level of
+the umbilicus. Excellent anæsthesia is obtained for the operation for
+radical cure of umbilical hernia, but anæsthesia above this level is
+not so constant, and is regarded by many authorities as unsafe.</p>
+
+<p>The procedure is of special value in cases in which a general
+anæsthetic is unsafe:—(1) In old enfeebled patients suffering from
+strangulated hernia, enlarged prostate, disease of the female pelvic
+organs, and other conditions where anæsthesia is necessary below the
+umbilicus. (2) In patients who are already suffering, or who are likely
+to suffer, from severe shock. The drug has the same effect on the nerve
+trunks of the cauda equina as on the peripheral nerves—it causes
+blocking of the centripetal sensory impulses which are such a potent
+factor in the causation of shock.</p>
+
+<p><span class="pagenum" id="Page_200">[200]</span></p>
+
+<p>(3) In diabetic gangrene spinal analgesia is the safest form of
+anæsthesia to employ.</p>
+
+
+<h3><b>Contra-Indications</b></h3>
+
+<p>Children up to the age of fourteen or so are apt to be frightened,
+and spinal analgesia is better avoided except in special cases. It
+is contra-indicated also in septic conditions on account of the
+possibility of septic meningitis resulting from metastasis of the
+infection, the drug having possibly the action of lowering the vitality
+of the cord and meninges. In tuberculosis and syphilis it is better
+avoided for the same reason. It should not be used where organic
+disease of the spinal cord or brain is already present.</p>
+
+
+<h3><b>Analgesia Produced by Freezing.</b></h3>
+
+<p>A transient analgesia can be produced by freezing the skin. An ether
+spray was formerly employed, but was found to be troublesome and
+inconvenient. The most convenient procedure consists in freezing the
+part by means of a spray of ethyl chloride. This drug is supplied in a
+glass cylinder with a very fine outlet so that it breaks up into a fine
+spray as it escapes. The cylinder is held about 8 or 10 inches from the
+patient’s skin, and pressure applied with the thumb to a stopcock on
+the neck of the cylinder. Under the influence of the heat of the hand
+the liquid escapes in a fine jet which impinges on the patient’s skin.
+Freezing takes place in a few seconds, the frozen patch becoming hard
+and white. The freezing can be hastened by blowing on the skin.</p>
+
+<p>This method is only suitable for the opening of small abscesses and
+other procedures requiring a very short anæsthesia. The anæsthesia is
+very imperfect, and only lasts for a few seconds. Many patients appear
+to have as much pain with this form of anæsthesia as without it.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_201">[201]</span></p>
+
+<h2 class="gesperrt">APPENDIX I.<br>
+<span class="subhed"><b>SOME EXPERIMENTAL OBSERVATIONS BY THE AUTHOR UPON THE PHYSICAL FACTS OF
+ETHER EVAPORATION.</b></span></h2></div>
+
+
+<p>The apparatus was very simple. It consisted of a pump which would
+propel air towards the ether bottle; a glass bottle containing ether,
+the roof of which was pierced by two tubes, one of which carried the
+air from pump to bottle, and the other from bottle to a Waller’s tube,
+where it was collected. The percentage of ether in the air was then
+estimated by Waller’s gravimetric method. The ether jar stood in a
+water bath which could be either left otherwise empty or filled up
+with water of known temperature. The following tables show some of the
+results. In each case, the air was propelled for five minutes, by which
+time the cooling effect upon the ether was very marked; the figures
+given are averages taken from several observations.</p>
+
+
+<p class="center p1">TABLE A.</p>
+
+<p class="smcap center sm">Air Blowing over Surface of Ether.</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctrtrbl">Temperature of Bath (Fahr.) before experiment.</td>
+    <td class="ctrtrb">Quantity of ether before experiment.</td>
+    <td class="ctrtrb">Rate of pump.</td>
+    <td class="ctrtrb">Temperature of ether (Fahr.) at end of experiment.</td>
+    <td class="ctrtrb">Percentage obtained.</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">75</td>
+    <td class="ctrr">100 c.c.</td>
+    <td class="ctrr">30</td>
+    <td class="ctrr">50 F.</td>
+    <td class="ctrr">12·7</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">85</td>
+    <td class="ctrr">100 c.c.</td>
+    <td class="ctrr">30</td>
+    <td class="ctrr">52 F.</td>
+    <td class="ctrr">12·8</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">75</td>
+    <td class="ctrr">100 c.c.</td>
+    <td class="ctrr">90</td>
+    <td class="ctrr">45 F.</td>
+    <td class="ctrr">8·7</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">85</td>
+    <td class="ctrr">100 c.c.</td>
+    <td class="ctrr">90</td>
+    <td class="ctrr">45 F.</td>
+    <td class="ctrr">8·8</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">No water in bath</td>
+    <td class="ctrr">100 c.c.</td>
+    <td class="ctrr">30</td>
+    <td class="ctrr">32 F.</td>
+    <td class="ctrr">8·2</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">No water in bath</td>
+    <td class="ctrr">100 c.c.</td>
+    <td class="ctrr">90</td>
+    <td class="ctrr">23 F.</td>
+    <td class="ctrr">5·4</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrl">No water in bath</td>
+    <td class="ctrr">200 c.c.</td>
+    <td class="ctrr">30</td>
+    <td class="ctrr">38 F.</td>
+    <td class="ctrr">9·6</td>
+  </tr>
+
+  <tr>
+    <td class="ctrrbl">No water in bath</td>
+    <td class="ctrrb">200 c.c.</td>
+    <td class="ctrrb">90</td>
+    <td class="ctrrb">29 F.</td>
+    <td class="ctrrb">6·6</td>
+  </tr>
+</table>
+
+<p><span class="pagenum" id="Page_202">[202]</span></p>
+
+
+<p class="center p1">TABLE B.</p>
+
+<p>Showing increased percentage obtained by “bubbling through” instead of
+“blowing over” ether—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctr smcap" colspan="2">Water Bath at 75° Fahr.</td>
+  </tr>
+
+  <tr>
+    <td class="ctr">Quantity of ether.</td>
+    <td class="ctr">Rate of pump.</td>
+  </tr>
+
+  <tr>
+    <td class="ctr">100 c.c.</td>
+    <td class="ctr">30</td>
+  </tr>
+</table>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="cht">Air blown over surface of ether gave percentage of ether</td>
+    <td class="cht">12·8</td>
+  </tr>  
+
+  <tr>
+    <td class="cht">Air bubbled <i>through</i> ether</td>
+    <td class="cht">23·8</td>
+  </tr>
+</table>
+
+
+<p class="center">TABLE C.</p>
+
+<p>Showing amounts of ether vaporised at varying pump rates. In each case,
+the temperature of the water bath was 75, and the initial amount of
+ether was 100 cc.—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctr">Pump Rate.</td>
+    <td class="ctr">Amount of Ether<br>Vaporised.</td>
+  </tr>
+
+  <tr>
+    <td class="ctr">30</td>
+    <td class="ctr">30 c.c.</td>
+  </tr>
+
+  <tr>
+    <td class="ctr">90</td>
+    <td class="ctr">38 c.c.</td>
+  </tr>
+</table>
+
+<p>These experiments justify one in drawing the following conclusions:—</p>
+
+<div class="blockquot">
+
+<p>1. The effect of a water bath has a marked effect in increasing
+the strength of the vapour yielded, but small variations in the
+temperature of the bath (as between 75 and 85 Fahr.) have but
+little effect.</p>
+
+<p>2. If ether is vaporising quickly, it cannot pick up heat from
+the water bath as quickly as it is losing its own heat. Though
+not shown in the tables, the actual loss of temperature on the
+water bath was small—about 2 degrees Fahr. during the five
+minutes experiment.</p>
+
+<p>3. The more forcible the blast of air blown over or through
+the ether, the less the percentage of ether yielded. Table C
+shows that this loss of percentage is not compensated for by an
+increase in the total amount vaporised.</p>
+</div>
+
+<p><span class="pagenum" id="Page_203">[203]</span></p>
+
+<p>Of course, these results only apply to the case of a strong current
+of air. If the current of air were <i>very</i> small, the ether could
+pick up heat as fast as it parted with it, and within moderate degrees
+a little increase of the air stream would increase the total amount of
+ether vaporised without reducing the percentage strength.</p>
+
+<p>These results are of some practical importance in connection with
+so-called “vapour anæsthesia” as given for instance by Shipway’s
+instrument (page 90), and in devising and using the ether chambers of
+intratracheal apparatus.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_204">[204]</span></p>
+
+<h2><span class="gesperrt">APPENDIX II.</span><br>
+<span class="subhed"><b>THE PERCENTAGE STRENGTH IN OPEN ETHER.</b></span></h2></div>
+
+<p>Hewitt and Syme (<i>Lancet</i>, 27th Jan. 1912) estimated the
+percentage of ether obtainable from an open mask with varying materials
+and quantities of the drug. The results are tabulated below:—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctr smcap" colspan="3">A.—A Whole Mask just Moist.</td>
+  </tr>
+
+  <tr>
+   <td class="ctr">Material stretched<br>on mask.</td>
+   <td class="ctr">Number of<br>layers.</td>
+   <td class="ctr">Percentage<br>obtained.</td>
+  </tr>
+
+  <tr>
+    <td class="cht1">Gauze</td>
+    <td class="right1">4</td>
+    <td class="right1">11</td>
+  </tr>
+
+  <tr>
+    <td class="cht1"></td>
+    <td class="right1">8</td>
+    <td class="right2">11·4</td>
+  </tr>
+
+  <tr>
+    <td class="cht1"></td>
+    <td class="right1">12</td>
+    <td class="right1">11</td>
+  </tr>
+
+  <tr>
+    <td class="cht1">Flannel</td>
+    <td class="right1">1</td>
+    <td class="right2">8·0</td>
+  </tr>
+
+  <tr>
+    <td class="cht1"></td>
+    <td class="right1">2</td>
+    <td class="right2">8·0</td>
+  </tr>
+
+  <tr>
+    <td class="cht1">Lint</td>
+    <td class="right1">1</td>
+    <td class="right2">10·0</td>
+  </tr>
+
+  <tr>
+    <td class="ctr smcap" colspan="3">B.—Whole Mask Wet.</td>
+  </tr>
+
+  <tr>
+    <td class="cht1">Gauze</td>
+    <td class="right1">4</td>
+    <td class="right1">12</td>
+  </tr>
+
+  <tr>
+    <td class="cht1"></td>
+    <td class="right1">8</td>
+    <td class="right2">13·4</td>
+  </tr>
+
+  <tr>
+    <td class="cht1"></td>
+    <td class="right1">12</td>
+    <td class="right2">14·0</td>
+  </tr>
+
+  <tr>
+    <td class="cht1">Flannel</td>
+    <td class="right1">1</td>
+    <td class="right2">8·0</td>
+  </tr>
+
+  <tr>
+    <td class="cht1"></td>
+    <td class="right1">2</td>
+    <td class="right2">8·0</td>
+  </tr>
+
+  <tr>
+    <td class="cht1">Lint</td>
+    <td class="right1">1</td>
+    <td class="right2">8·0</td>
+  </tr>
+</table>
+
+<p>By excessive douching the observers were able to obtain 17 per cent.</p>
+
+<p>In these results, air and ether vapour were drawn by a pump through
+the material to imitate the inspiration, but no attempt seems to have
+been made to imitate expiration. The effect upon the material used of
+moisture condensed from the expired air is<span class="pagenum" id="Page_205">[205]</span> not taken into account
+in these experiments. This is a serious hiatus in the argument,
+particularly as regards lint. This material in actual use rapidly
+becomes quite sodden, and ether will not vaporise from it properly.</p>
+
+<p>In spite of this fault, these observations may probably be taken as
+being reasonably accurate.</p>
+
+<p>With them may be compared the figures of Karl Connell, who, working
+with quite accurate methods, estimated the percentages of ether
+necessary to induce and maintain anæsthesia:—</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctr">Period of Anæsthesia.</td>
+    <td class="ctr">Percentage.</td>
+  </tr>
+
+  <tr>
+    <td class="cht">First 5 minutes (<i>i.e.</i> induction)</td>
+    <td class="right1">18</td>
+  </tr>
+
+  <tr>
+    <td class="cht">Next 25&emsp;„</td>
+    <td class="right1">14</td>
+  </tr>
+
+  <tr>
+    <td class="cht">Next 30&emsp;„</td>
+    <td class="right1">12</td>
+  </tr>
+
+  <tr>
+    <td class="cht">Next 60&emsp;„</td>
+    <td class="right2">12·8</td>
+  </tr>
+</table>
+
+<p>“Bad” subjects on the average required an extra 4 per cent. during
+first half hour, feeble patients required 2 per cent. less.
+(<i>Journal</i> of the American Medical Association, 22nd March 1913).</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_206">[206]</span></p>
+
+<h2><span class="gesperrt">APPENDIX III.</span><br>
+<span class="subhed"><b>THE ACTION OF ANÆSTHETICS UPON THE BLOOD.</b></span></h2></div>
+
+
+<h3><i>The Blood Gases in Anæsthesia.</i></h3>
+
+<p>Buckmaster and Gardner (<i>Journal of Physiology</i>, vol. xli.,
+p. 246), analysed the blood gases in various stages of chloroform
+anæsthesia, and some of their results are shown below in tabular form.
+They show a very definite reduction in the oxygen content of the blood.
+So far as one gathers from the text of the paper, the animals were
+not subjected to any considerable trauma during the progress of the
+anæsthesia, so that the figures arrived at with regard to the CO<sub>2</sub>
+content do not bear upon the Acapnia question. If there was no trauma,
+there would be no deep breathing, and a reduction of CO<sub>2</sub> could not
+be expected.</p>
+
+<table class="smaller" style="max-width: 50em">
+  <tr>
+    <td class="ctrtrbl" rowspan="2"></td>
+    <td class="ctrtrb" colspan="3">Average volume in<br>c.c. per 100 c.c.<br>of blood</td>
+    <td class="ctrtrb" colspan="3">Average composition<br>per cent. of gas</td>
+    <td class="ctr1trb" rowspan="2">Relation<br>of<br>O<sub>2</sub> to CO<sub>2</sub></td>
+  </tr>
+
+  <tr>
+    <td class="ctrrb">CO<sub>2</sub></td>
+    <td class="ctrrb">O<sub>2</sub></td>
+    <td class="ctrrb">Nitr.</td>
+    <td class="ctrrb">CO<sub>2</sub></td>
+    <td class="ctrrb">O<sub>2</sub></td>
+    <td class="ctrrb">Nitr.</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Normal cats.</td>
+    <td class="rightr">25·07</td>
+    <td class="rightr">13·60</td>
+    <td class="rightr">1·00</td>
+    <td class="rightr">63·2&nbsp;</td>
+    <td class="rightr">34·28</td>
+    <td class="rightr">2·52</td>
+    <td class="rightr">1 to 1·84</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Reflexes just re-appearing</td>
+    <td class="rightr">29·02</td>
+    <td class="rightr">11·49</td>
+    <td class="rightr">1·33</td>
+    <td class="rightr">65·06</td>
+    <td class="rightr">25·44</td>
+    <td class="rightr">2·87</td>
+    <td class="rightr">1 to 2·55</td>
+  </tr>
+
+  <tr>
+    <td class="chtrl">Reflexes just disappearing</td>
+    <td class="rightr">29·57</td>
+    <td class="rightr">7·78</td>
+    <td class="rightr">2·15</td>
+    <td class="rightr">69·14</td>
+    <td class="rightr">18·17</td>
+    <td class="rightr">5·09</td>
+    <td class="rightr">1 to 3·8&ensp;</td>
+  </tr>
+
+  <tr>
+    <td class="chtrbl">2nd Stage Anæsthesia</td>
+    <td class="rightrb">36·00</td>
+    <td class="rightrb">8·14</td>
+    <td class="rightrb">1·49</td>
+    <td class="rightrb">71·27</td>
+    <td class="rightrb">16·12</td>
+    <td class="rightrb">2·95</td>
+    <td class="rightrb">1 to 4·32</td>
+  </tr>
+</table>
+
+<p><span class="pagenum" id="Page_207">[207]</span></p>
+
+
+<h3><i>Other Blood changes in Anæsthesia.</i></h3>
+
+<p>Hamburger and Ewing (<i>Journal</i> of the American Medical Assoc.
+1908) examined the blood changes incidental to surgical anæsthesia.
+Their results may be condensed as follows:—</p>
+
+<p><i>Nitrous Oxide.</i>—Hæmoglobin is not permanently decreased and
+no anæmia follows the administration. Hæmolysis is not increased.
+The coagulation time of the blood is not always affected in the same
+direction. Usually it is slightly increased.</p>
+
+<p><i>Ether.</i>—The hæmoglobin is slightly reduced and anæmia persists
+for seven to ten days. Hæmolysis is not however materially increased.
+There is some evidence of blood inspissation. The coagulation time is
+markedly increased.</p>
+
+<p><i>Chloroform.</i>—The hæmoglobin is reduced and a distinct anæmia
+produced. Hæmolysis is definitely increased. There is a slight increase
+in the coagulation time.</p>
+<hr class="chap x-ebookmaker-drop">
+
+<div class="chapter">
+<p><span class="pagenum" id="Page_209">[209]</span></p>
+
+<h2>INDEX.</h2>
+</div>
+
+<p class="p-index">A</p>
+
+<ul>
+  <li class="i1">Abdominal operations,
+    <a href="#Page_ix">ix</a>,
+    <a href="#Page_7">7</a></li>
+  <li class="i2">local anæsthesia in,
+    <a href="#Page_187">187</a></li>
+
+  <li class="i1">Abdominal muscles, rigidity of,
+    <a href="#Page_19">19</a></li>
+
+  <li class="i1">Abnormalities of anæsthesia, minor,
+    <a href="#Page_38">38</a></li>
+  <li class="i2">major,
+    <a href="#Page_140">140</a></li>
+
+  <li class="i1" id="Acapnia">Acapnia,
+    <a href="#Page_10">10</a>,
+    <a href="#Page_29">29</a>,
+    <a href="#Page_39">39</a></li>
+
+  <li class="i1">Accidents of anæsthesia,
+    <a href="#Page_140">140</a></li>
+
+  <li class="i1">Acetonuria,
+    <a href="#Page_153">153</a></li>
+
+  <li class="i1">Acidosis,
+    <a href="#Page_153">153</a></li>
+
+  <li class="i1">Adenoids,
+    <a href="#Page_127">127</a>,
+    <a href="#Page_166">166</a></li>
+  <li class="i2">in status lymphaticus,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Adrenalin,
+    <a href="#Page_175">175</a></li>
+  <li class="i2">danger of, with chloroform,
+    <a href="#Page_113">113</a>,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Aedentulous patients,
+    <a href="#Page_23">23</a></li>
+
+  <li class="i1">After-effects of anæsthetics, <i>see</i> Sequelae</li>
+
+  <li class="i1">Ages, dosage of morphia at various,
+    <a href="#Page_45">45</a></li>
+  <li class="i2">selection of anæsthetic at various,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Airshaft, natural,
+    <a href="#Page_96">96</a></li>
+
+  <li class="i1">Airway, natural,
+    <a href="#Page_15">15</a>,
+    <a href="#Page_31">31</a>,
+    <a href="#Page_114">114</a>,
+    <a href="#Page_145">145</a></li>
+  <li class="i2">artificial,
+    <a href="#Page_23">23</a></li>
+
+  <li class="i1">Alcoholics, anæsthesia in,
+    <a href="#Page_2">2</a>,
+    <a href="#Page_87">87</a>,
+    <a href="#Page_103">103</a>,
+    <a href="#Page_137">137</a>,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Alkaloids,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_43">43</a>,
+    <a href="#Page_88">88</a>,
+    <a href="#Page_103">103</a></li>
+
+  <li class="i1">Aneurysm,
+    <a href="#Page_56">56</a></li>
+
+  <li class="i1">Anoci-association,
+    <a href="#Page_11">11</a></li>
+
+  <li class="i1">Anoxæmia,
+    <a href="#Page_15">15</a></li>
+
+  <li class="i1">Arm, management of in anæsthesia,
+    <a href="#Page_157">157</a></li>
+  <li class="i2">regional anæsthesia of,
+    <a href="#Page_181">181</a></li>
+
+  <li class="i1">Arteries, spouting of,
+    <a href="#Page_x">x</a>,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Arterio-sclerosis,
+    <a href="#Page_56">56</a>,
+    <a href="#Page_167">167</a></li>
+
+  <li class="i1">Artificial respiration,
+    <a href="#Page_146">146</a></li>
+
+  <li class="i1">Asphyxia,
+    <a href="#Page_15">15</a></li>
+
+  <li class="i1">Athetosis,
+    <a href="#Page_38">38</a></li>
+
+  <li class="i1">Atropine,
+    <a href="#Page_43">43</a>,
+    <a href="#Page_45">45</a>,
+    <a href="#Page_112">112</a>,
+    <a href="#Page_147">147</a></li>
+
+  <li class="i1">Auer and Meltzer,
+    <a href="#Page_96">96</a></li>
+</ul>
+
+<p class="p-index">B</p> 
+
+<ul>
+  <li class="i1">Barth 3-way tap,
+    <a href="#Page_50">50</a></li>
+
+  <li class="i1">Bicarbonate of soda in acidosis,
+    <a href="#Page_156">156</a></li>
+
+  <li class="i1">Bladder, reflexes from,
+    <a href="#Page_39">39</a>,
+    <a href="#Page_168">168</a></li>
+  <li class="i2">local anæsthesia in operations upon,
+    <a href="#Page_190">190</a></li>
+
+  <li class="i1">Blistering, by chloroform,
+    <a href="#Page_109">109</a></li>
+
+  <li class="i1">Blood, changes in, during anæsthesia,
+    <a href="#Page_207">207</a></li>
+  <li class="i2">spouting of, from cut arteries,
+    <a href="#Page_x">x</a>,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Blood-pressure, in natural sleep,
+    <a href="#Page_1">1</a></li>
+  <li class="i2">in shock,
+    <a href="#Page_6">6</a></li>
+  <li class="i2">in asphyxia,
+    <a href="#Page_17">17</a></li>
+  <li class="i2">in nitrous oxide,
+    <a href="#Page_46">46</a></li>
+  <li class="i2">in ether,
+    <a href="#Page_75">75</a></li>
+  <li class="i2">in chloroform,
+    <a href="#Page_110">110</a></li>
+  <li class="i2">in ethyl chloride,
+    <a href="#Page_122">122</a></li>
+  <li class="i2">clinical observation of,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Blowing respiration,
+    <a href="#Page_34">34</a>,
+    <a href="#Page_89">89</a></li>
+
+  <li class="i1">Boothby, on ether percentages,
+    <a href="#Page_99">99</a></li>
+
+  <li class="i1">Boyle, Mr Leonard,
+    <a href="#Page_70">70</a></li>
+
+  <li class="i1">Brachial plexus, nerve blocking in,
+    <a href="#Page_181">181</a></li>
+
+  <li class="i1">Brain, <i>see</i> <a href="#Nervous">Nervous System</a></li>
+  <li class="i2">local anæsthesia for operation upon,
+    <a href="#Page_191">191</a></li>
+
+  <li class="i1">Breath-holding,
+    <a href="#Page_34">34</a>,
+    <a href="#Page_112">112</a>,
+    <a href="#Page_114">114</a></li>
+
+  <li class="i1">Breathing, deep (<i>see</i> <a href="#Acapnia">Acapnia</a>)</li>
+
+  <li class="i1">Bronchitis,
+    <a href="#Page_150">150</a></li>
+</ul>
+
+<p class="p-index">C</p>
+
+<ul>
+  <li class="i1">Carbon-dioxide,
+    <a href="#Page_10">10</a>,
+    <a href="#Page_18">18</a>,
+    <a href="#Page_206">206</a></li>
+
+  <li class="i1">Cardiac cyanosis,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Cardiac disease,
+    <a href="#Page_107">107</a></li>
+
+  <li class="i1">Cardiac failure (<i>see</i> <a href="#Syncope">Syncope</a>)</li>
+
+  <li class="i1">Castration, anæsthesia in,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">C.E. mixture,
+    <a href="#Page_83">83</a>,
+    <a href="#Page_134">134</a>,
+    <a href="#Page_137">137</a></li>
+
+  <li class="i1">Cells, nerve, changes in,
+    <a href="#Page_5">5</a></li>
+
+  <li class="i1">Centripetal impulses,
+    <a href="#Page_6">6</a></li>
+
+  <li class="i1">Children,
+    <a href="#Page_45">45</a>,
+    <a href="#Page_94">94</a>,
+    <a href="#Page_125">125</a>,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Chloretone,
+    <a href="#Page_93">93</a></li>
+
+  <li class="i1">Chloride of ethyl (<i>see</i> <a href="#Ethyl">Ethyl Chloride</a>)</li>
+
+  <li class="i1">Chloroform, administration of,
+    <a href="#Page_113">113</a></li>
+  <li class="i2">decomposition of,
+    <a href="#Page_109">109</a></li>
+  <li class="i2">delayed poisoning by,
+    <a href="#Page_153">153</a></li>
+  <li class="i2">physiology of,
+    <a href="#Page_109">109</a></li>
+
+  <li class="i1">Choice of anæsthetics,
+    <a href="#Page_162">162</a></li>
+
+  <li class="i1">Circulation, observation of,
+    <a href="#Page_x">x</a>,
+    <a href="#Page_37">37</a></li>
+  <li class="i2">in shock,
+    <a href="#Page_10">10</a></li>
+  <li class="i2">in asphyxia,
+    <a href="#Page_17">17</a></li>
+  <li class="i2">in valved breathing,
+    <a href="#Page_29">29</a></li>
+  <li class="i2">in nitrous oxide,
+    <a href="#Page_46">46</a></li>
+  <li class="i2">in ether,
+    <a href="#Page_75">75</a></li>
+  <li class="i2">in chloroform,
+    <a href="#Page_110">110</a></li>
+  <li class="i2">in ethyl chloride,
+    <a href="#Page_122">122</a></li>
+  <li class="i2">in C.E. mixture,
+    <a href="#Page_131">131</a></li>
+  <li class="i2">failure of (<i>see</i> <a href="#Syncope">Syncope</a>)</li>
+
+  <li class="i1">Circumcision, anæsthesia in,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Clarke’s apparatus,
+    <a href="#Page_69">69</a></li>
+
+  <li class="i1">Clenching of Jaws,
+    <a href="#Page_15">15</a>,
+    <a href="#Page_24">24</a></li>
+
+  <li class="i1">Clinical phenomena of asphyxia,
+    <a href="#Page_18">18</a></li>
+  <li class="i2">of normal anæsthesia,
+    <a href="#Page_33">33</a></li>
+
+  <li class="i1">Closed ether,
+    <a href="#Page_78">78</a></li>
+
+  <li class="i1">Closed method, features of,
+    <a href="#Page_29">29</a></li>
+
+  <li class="i1">Clover’s inhaler,
+    <a href="#Page_78">78</a>,
+    <a href="#Page_138">138</a></li>
+
+  <li class="i1">Cocaine,
+    <a href="#Page_170">170</a></li>
+
+  <li class="i1">Collapse (<i>see</i> <a href="#Syncope">Syncope</a>)</li>
+
+  <li class="i1">Conduction of nerve impulses,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1">Connell, Karl,
+    <a href="#Page_90">90</a>,
+    <a href="#Page_205">205</a></li>
+
+  <li class="i1">Conjunctival reflex,
+    <a href="#Page_31">31</a>,
+    <a href="#Page_35">35</a></li>
+
+  <li class="i1">Convulsions,
+    <a href="#Page_17">17</a></li>
+
+  <li class="i1">Corneal reflex,
+    <a href="#Page_32">32</a>,
+    <a href="#Page_35">35</a></li>
+
+  <li class="i1">Crile, Prof.,
+    <a href="#Page_5">5</a>,
+    <a href="#Page_9">9</a></li>
+
+  <li class="i1">Crowing respiration,
+    <a href="#Page_16">16</a>,
+    <a href="#Page_169">169</a></li>
+  <li class="i2">night crowing,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Cyanosis,
+    <a href="#Page_18">18</a>,
+    <a href="#Page_37">37</a>,
+    <a href="#Page_53">53</a></li>
+
+  <li class="i1">Cylinders for nitrous oxide,
+    <a href="#Page_43">43</a></li>
+  <li class="i2">for oxygen,
+    <a href="#Page_64">64</a></li>
+</ul>
+
+<p class="p-index">D</p> 
+ 
+<ul>
+  <li class="i1">Dangers of chloroform, Prof. L. Hill upon,
+    <a href="#Page_120">120</a></li>
+
+  <li class="i1">Death, causes of,
+    <a href="#Page_17">17</a>,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_140">140</a>,
+    <a href="#Page_144">144</a>,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Decomposition of chloroform,
+    <a href="#Page_109">109</a></li>
+  <li class="i2">of ether,
+    <a href="#Page_74">74</a></li>
+
+  <li class="i1">Deep breathing,
+    <a href="#Page_10">10</a></li>
+
+  <li class="i1">Degrees of anæsthesia,
+    <a href="#Page_31">31</a></li>
+
+  <li class="i1" id="Dental">Dental anæsthesia,
+    <a href="#Page_54">54</a>,
+    <a href="#Page_57">57</a>,
+    <a href="#Page_128">128</a>,
+    <a href="#Page_131">131</a>,
+    <a href="#Page_163">163</a></li>
+
+  <li class="i1">Depth of anæsthesia,
+    <a href="#Page_36">36</a></li>
+
+  <li class="i1">Dextrose in acidosis,
+    <a href="#Page_156">156</a></li>
+
+  <li class="i1">Difficulties of anæsthesia, major,
+    <a href="#Page_140">140</a></li>
+  <li class="i2">minor,
+    <a href="#Page_38">38</a></li>
+
+  <li class="i1">Dilatation of pupils,
+    <a href="#Page_5">5</a>,
+    <a href="#Page_17">17</a>,
+    <a href="#Page_35">35</a>,
+    <a href="#Page_53">53</a>,
+    <a href="#Page_66">66</a>,
+    <a href="#Page_125">125</a>,
+    <a href="#Page_136">136</a>,
+    <a href="#Page_141">141</a>,
+    <a href="#Page_143">143</a></li>
+
+  <li class="i1">Disease, relation of anæsthesia to,
+    <a href="#Page_166">166</a></li>
+  <li class="i2">acute infectious,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Dislocations, anæsthesia in reduction of,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Dorsal position,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Dosimetric method for chloroform,
+    <a href="#Page_114">114</a></li>
+  <li class="i2">for ether,
+    <a href="#Page_90">90</a></li>
+
+  <li class="i1">Dott, Mr N., direct laryngoscope,
+    <a href="#Page_104">104</a></li>
+
+  <li class="i1">Douche method,
+    <a href="#Page_20">20</a></li>
+
+  <li class="i1">Dread (<i>see</i> <a href="#Fear">Fear</a>)</li>
+
+  <li class="i1">Drop bottles; chloroform,
+    <a href="#Page_117">117</a></li>
+  <li class="i2">ether,
+    <a href="#Page_83">83</a></li>
+
+  <li class="i1">Drop method,
+    <a href="#Page_30">30</a>,
+    <a href="#Page_83">83</a></li>
+
+  <li class="i1">Drugs for local and spinal anæsthesia,
+    <a href="#Page_170">170 to 174</a></li>
+</ul>
+
+<p class="p-index">E</p>
+
+<ul>
+  <li class="i1">Emphysema,
+    <a href="#Page_167">167</a></li>
+
+  <li class="i1">Empyæma,
+    <a href="#Page_167">167</a>,
+    <a href="#Page_187">187</a></li>
+
+  <li class="i1">Enema, before operation,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Ether,
+    <a href="#Page_74">74</a>, <i>et seq.</i></li>
+  <li class="i2">closed,
+    <a href="#Page_78">78</a></li>
+  <li class="i2">intratracheal,
+    <a href="#Page_96">96</a></li>
+  <li class="i2" id="Ether">open,
+    <a href="#Page_83">83</a></li>
+  <li class="i2">physiology of,
+    <a href="#Page_75">75</a></li>
+  <li class="i2">rectal,
+    <a href="#Page_93">93</a></li>
+  <li class="i2">warmed vapour,
+    <a href="#Page_90">90</a></li>
+
+  <li class="i1">Ether, respiratory sequelæ of,
+    <a href="#Page_150">150</a></li>
+
+  <li class="i1">Ether tremor,
+    <a href="#Page_38">38</a></li>
+
+  <li class="i1" id="Ethyl">Ethyl chloride,
+    <a href="#Page_122">122</a>, <i>et seq.</i></li>
+  <li class="i2">combined with nitrous oxide,
+    <a href="#Page_128">128</a></li>
+  <li class="i2">freezing anæsthesia by,
+    <a href="#Page_200">200</a></li>
+
+  <li class="i1">Eucain,
+    <a href="#Page_174">174</a></li>
+
+  <li class="i1">Excitement (<i>see</i> <a href="#Struggling">Struggling</a>)</li>
+
+  <li class="i1">Extraction of teeth (<i>see</i> <a href="#Dental">Dental Anæsthesia</a>)</li>
+
+  <li class="i1">Eye reflexes, definition of,
+    <a href="#Page_31">31</a></li>
+</ul>
+
+<p class="p-index">F</p>
+
+<ul>
+  <li class="i1">Face-down posture,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Face, adaptation of masks to,
+    <a href="#Page_21">21</a>,
+    <a href="#Page_52">52</a>,
+    <a href="#Page_83">83</a></li>
+
+  <li class="i1">Face-pieces for nitrous oxide,
+    <a href="#Page_51">51</a></li>
+
+  <li class="i1">False anæsthesia,
+    <a href="#Page_41">41</a></li>
+
+  <li class="i1">Faradism of motor nerves in anæsthesia,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1">Fat patients,
+    <a href="#Page_158">158</a>,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Fatty changes after anæsthesia,
+    <a href="#Page_153">153</a></li>
+
+  <li class="i1" id="Fear">, effects of,
+    <a href="#Page_9">9</a></li>
+  <li class="i2">prevention of,
+    <a href="#Page_11">11</a>,
+    <a href="#Page_43">43</a>,
+    <a href="#Page_88">88</a></li>
+
+  <li class="i1">Feeble patients,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Ferguson, Dr., W. J.,
+    <a href="#Page_87">87</a></li>
+
+  <li class="i1">Fingers, regional anæsthesia for,
+    <a href="#Page_184">184</a></li>
+
+  <li class="i1">Flame, open, dangers of,
+    <a href="#Page_74">74</a>,
+    <a href="#Page_104">104</a></li>
+
+  <li class="i1">Forceps, tongue,
+    <a href="#Page_24">24</a></li>
+
+  <li class="i1">Food before anæsthesia,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Foreign bodies in the larynx,
+    <a href="#Page_16">16</a></li>
+
+  <li class="i1">Freezing analgesia,
+    <a href="#Page_201">201</a></li>
+
+  <li class="i1">Fright (<i>see</i> <a href="#Fear">Fear</a>)</li>
+</ul>
+
+<p class="p-index">G</p> 
+
+<ul>
+  <li class="i1">Gags,
+    <a href="#Page_25">25</a></li>
+
+  <li class="i1">Gardner, Mr Bellamy,
+    <a href="#Page_23">23</a>,
+    <a href="#Page_24">24</a>,
+    <a href="#Page_83">83</a></li>
+
+  <li class="i1">Gas and air,
+    <a href="#Page_54">54</a></li>
+
+  <li class="i1">Gas and ether,
+    <a href="#Page_138">138</a></li>
+
+  <li class="i1">Gas and ethyl chloride,
+    <a href="#Page_128">128</a></li>
+
+  <li class="i1">Gas-oxygen,
+    <a href="#Page_60">60</a></li>
+
+  <li class="i1">Gasping,
+    <a href="#Page_40">40</a></li>
+
+  <li class="i1">Genito-urinary operations,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Glossotilt,
+    <a href="#Page_24">24</a></li>
+
+  <li class="i1">Glottis, spasm of,
+    <a href="#Page_16">16</a>,
+    <a href="#Page_20">20</a>,
+    <a href="#Page_26">26</a>,
+    <a href="#Page_105">105</a></li>
+
+  <li class="i1" id="Goitre">Goitre, anæsthesia for,
+    <a href="#Page_160">160</a>,
+    <a href="#Page_185">185</a></li>
+
+  <li class="i1">Goitre, exopthalmic,
+    <a href="#Page_9">9</a>,
+    <a href="#Page_167">167</a></li>
+
+  <li class="i1">Grey and Parsons on shock,
+    <a href="#Page_6">6</a></li>
+
+  <li class="i1">Guy, Dr Wm.,
+    <a href="#Page_128">128</a></li>
+
+  <li class="i1">Guy-Ross, gas oxygen method,
+    <a href="#Page_131">131</a></li>
+
+  <li class="i1">Gwathmey, warmed ether vapour,
+    <a href="#Page_90">90</a></li>
+  <li class="i2">oil-ether,
+    <a href="#Page_93">93</a></li>
+</ul>
+
+<p class="p-index">H</p> 
+
+<ul>
+  <li class="i1">Hæmorrhage, as a factor in shock production,
+    <a href="#Page_9">9</a></li>
+  <li class="i2">observation of, by anæsthetist,
+    <a href="#Page_x">x</a>,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Hæmorrhoids, local anæsthesia for,
+    <a href="#Page_191">191</a></li>
+
+  <li class="i1">Harcourt, Vernon,
+    <a href="#Page_114">114</a></li>
+
+  <li class="i1">Head and neck operations, position for,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Head and neck, raising,
+    <a href="#Page_152">152</a></li>
+  <li class="i2">lowering,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_145">145</a></li>
+  <li class="i2">extra pillow in deep chested patients,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Heart, failure in asphyxia,
+    <a href="#Page_17">17</a></li>
+  <li class="i2">observation of,
+    <a href="#Page_37">37</a></li>
+  <li class="i2">action of ether upon,
+    <a href="#Page_75">75</a></li>
+  <li class="i2">of chloroform upon,
+    <a href="#Page_110">110</a></li>
+  <li class="i2">of ethyl chloride upon,
+    <a href="#Page_122">122</a></li>
+  <li class="i2">failure of, in secondary syncope,
+    <a href="#Page_144">144</a></li>
+
+  <li class="i1">Heart disease, anæsthetics in,
+    <a href="#Page_167">167</a></li>
+
+  <li class="i1">Henderson, Yandell,
+    <a href="#Page_10">10</a>,
+    <a href="#Page_29">29</a></li>
+
+  <li class="i1">Hernia, local anæsthesia in,
+    <a href="#Page_189">189</a></li>
+
+  <li class="i1">Heroin,
+    <a href="#Page_44">44</a></li>
+
+  <li class="i1">Hewitt, Sir Frederick,
+    <a href="#Page_22">22</a>,
+    <a href="#Page_50">50</a>,
+    <a href="#Page_62">62</a>,
+    <a href="#Page_81">81</a>,
+    <a href="#Page_137">137</a></li>
+
+  <li class="i1">Hill’s direct laryngoscope,
+    <a href="#Page_104">104</a></li>
+
+  <li class="i1">Hill, Prof. Leonard,
+    <a href="#Page_111">111</a>,
+    <a href="#Page_120">120</a></li>
+
+  <li class="i1">Hornabrook,
+    <a href="#Page_87">87</a>,
+    <a href="#Page_123">123</a></li>
+
+  <li class="i1">Hydrochloric acid, as an impurity in chloroform,
+    <a href="#Page_109">109</a></li>
+
+  <li class="i1">Hypnotics,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Hypodermic medication,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_42">42</a></li>
+</ul>
+
+<p class="p-index">I</p> 
+
+<ul>
+  <li class="i1">Impurities of anæsthetics,
+    <a href="#Page_74">74</a>,
+    <a href="#Page_109">109</a>,
+    <a href="#Page_122">122</a></li>
+
+  <li class="i1">Infiltration analgesia,
+    <a href="#Page_175">175</a></li>
+
+  <li class="i1">Inhalers, Clover,
+    <a href="#Page_78">78</a></li>
+  <li class="i2">Clarke,
+    <a href="#Page_68">68</a></li>
+  <li class="i2">Guy,
+    <a href="#Page_128">128</a></li>
+  <li class="i2">Guy-Ross,
+    <a href="#Page_130">130</a></li>
+  <li class="i2">Hewitt,
+    <a href="#Page_50">50</a>,
+    <a href="#Page_62">62</a>,
+    <a href="#Page_81">81</a></li>
+  <li class="i2">Junker’s,
+    <a href="#Page_115">115</a></li>
+  <li class="i2">Ormsby,
+    <a href="#Page_81">81</a></li>
+  <li class="i2">Paterson,
+    <a href="#Page_58">58</a></li>
+  <li class="i2">Rendle,
+    <a href="#Page_135">135</a></li>
+
+  <li class="i1">Inhibition, vagal,
+    <a href="#Page_111">111</a>,
+    <a href="#Page_143">143</a></li>
+
+  <li class="i1">Intestinal obstruction,
+    <a href="#Page_141">141</a>,
+    <a href="#Page_189">189</a></li>
+
+  <li class="i1">Intranasal surgery,
+    <a href="#Page_160">160</a>,
+    <a href="#Page_166">166</a>,
+    <a href="#Page_192">192</a></li>
+
+  <li class="i1">Intratracheal method,
+    <a href="#Page_96">96</a></li>
+  <li class="i2">Kelly’s instrument for,
+    <a href="#Page_100">100</a></li>
+  <li class="i2">Shipway’s,
+    <a href="#Page_101">101</a></li>
+
+  <li class="i1">Inversion, Leonard Hill’s experiments upon,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_111">111</a></li>
+</ul>
+
+<p class="p-index">J</p> 
+ 
+<ul>
+  <li class="i1">Jactitations,
+    <a href="#Page_53">53</a></li>
+
+  <li class="i1">Jaundice,
+    <a href="#Page_154">154</a></li>
+
+  <li class="i1">Jaws, clenching of,
+    <a href="#Page_15">15</a>,
+    <a href="#Page_26">26</a></li>
+  <li class="i2">falling back of,
+    <a href="#Page_16">16</a></li>
+  <li class="i2">operations upon,
+    <a href="#Page_166">166</a></li>
+  <li class="i2">management of, in anæsthesia,
+    <a href="#Page_23">23</a>,
+    <a href="#Page_83">83</a></li>
+
+  <li class="i1">Joints, anæsthesia in dislocation of,
+    <a href="#Page_164">164</a></li>
+
+  <li class="i1">Junker’s inhaler,
+    <a href="#Page_115">115</a></li>
+</ul>
+
+<p class="p-index">K</p> 
+
+<ul>
+  <li class="i1">Kidney, position for operations upon,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Kelly’s intratracheal instrument,
+    <a href="#Page_100">100</a></li>
+</ul>
+
+<p class="p-index">L</p>
+
+<ul>
+  <li class="i1">Labour, anæsthesia in,
+    <a href="#Page_44">44</a>,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Lane, Sir Arbuthnott,
+    <a href="#Page_14">14</a></li>
+
+  <li class="i1">Laryngeal stridor,
+    <a href="#Page_16">16</a>,
+    <a href="#Page_20">20</a>,
+    <a href="#Page_26">26</a>,
+    <a href="#Page_40">40</a>,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Levy, Goodman,
+    <a href="#Page_112">112</a>,
+    <a href="#Page_145">145</a></li>
+
+  <li class="i1">Light anæsthesia, dangers of, in chloroform,
+    <a href="#Page_9">9</a>,
+    <a href="#Page_112">112</a></li>
+  <li class="i2">Levy’s views,
+    <a href="#Page_113">113</a></li>
+
+  <li class="i1">Light reflex,
+    <a href="#Page_32">32</a></li>
+
+  <li class="i1">Local anæsthesia,
+    <a href="#Page_170">170</a> <i>et seq.</i></li>
+
+  <li class="i1">Lowering of head and shoulders,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_145">145</a></li>
+
+  <li class="i1">Lumbar puncture, site for,
+    <a href="#Page_196">196</a></li>
+
+  <li class="i1">Lungs, ventilation of, by normal breathing,
+    <a href="#Page_96">96</a></li>
+  <li class="i2">by intratracheal method,
+    <a href="#Page_97">97</a></li>
+
+  <li class="i1">Lymphatism,
+    <a href="#Page_148">148</a></li>
+</ul>
+
+<p class="p-index">M</p> 
+
+<ul>
+  <li class="i1">Malcolm, J. D.,
+    <a href="#Page_9">9</a></li>
+
+  <li class="i1">Marshall, Dr Geoffrey,
+    <a href="#Page_70">70</a></li>
+
+  <li class="i1">Masks for chloroform,
+    <a href="#Page_110">110</a></li>
+  <li class="i2">for ether,
+    <a href="#Page_82">82</a></li>
+  <li class="i2">for perhalation method,
+    <a href="#Page_28">28</a></li>
+
+  <li class="i1">Massage of heart,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Mechanical asphyxia,
+    <a href="#Page_15">15</a></li>
+
+  <li class="i1">Meltzer and Auer, on intratracheal method,
+    <a href="#Page_96">96</a></li>
+
+  <li class="i1">Menstruation,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Micturition before nitrous oxide,
+    <a href="#Page_51">51</a></li>
+
+  <li class="i1">Mixtures, C. E.,
+    <a href="#Page_83">83</a>,
+    <a href="#Page_134">134</a>,
+    <a href="#Page_137">137</a></li>
+  <li class="i2">of nitrous oxide and oxygen,
+    <a href="#Page_60">60</a></li>
+  <li class="i2">of nitrous oxide and ethyl chloride,
+    <a href="#Page_128">128</a></li>
+
+  <li class="i1">Morphine,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_43">43</a>,
+    <a href="#Page_152">152</a></li>
+
+  <li class="i1">Mouth, breathing through,
+    <a href="#Page_22">22</a></li>
+
+  <li class="i1">Mouth, operations upon,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Mouth props,
+    <a href="#Page_22">22</a></li>
+
+  <li class="i1">Mucus in air passages,
+    <a href="#Page_40">40</a></li>
+
+  <li class="i1">Musculo-spiral paralysis,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Muscles in anæsthesia,
+    <a href="#Page_ix">ix</a>,
+    <a href="#Page_3">3</a>,
+    <a href="#Page_19">19</a>,
+    <a href="#Page_34">34</a></li>
+
+  <li class="i1">Muscle tone,
+    <a href="#Page_3">3</a>,
+    <a href="#Page_19">19</a>,
+    <a href="#Page_53">53</a></li>
+</ul>
+
+<p class="p-index">N</p> 
+
+<ul>
+  <li class="i1">Nasal breathing,
+    <a href="#Page_23">23</a>,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Naso-pharyngeal catarrh,
+    <a href="#Page_151">151</a></li>
+
+  <li class="i1">Nasal methods of giving nitrous oxide,
+    <a href="#Page_57">57</a></li>
+
+  <li class="i1">Nasal tube for Junker’s bottle,
+    <a href="#Page_119">119</a></li>
+
+  <li class="i1">Neck, position of,
+    <a href="#Page_20">20</a></li>
+  <li class="i2">relaxation of muscles of,
+    <a href="#Page_21">21</a></li>
+  <li class="i2">posture for operation upon,
+    <a href="#Page_159">159</a></li>
+  <li class="i2">tumours and inflammatory swellings in,
+    <a href="#Page_7">7</a>,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Nephritis, influence of, upon choice of anæsthetics,
+    <a href="#Page_77">77</a>,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1" id="Nervous">Nervous system, effects of anæsthetics upon,
+    <a href="#Page_2">2</a>,
+    <a href="#Page_75">75</a></li>
+
+  <li class="i1">Nerves, peripheral, unaffected by anæsthetics,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1">Nerve blocking,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_179">179</a></li>
+
+  <li class="i1">Night-crowing,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Nitrous oxide,
+    <a href="#Page_46">46</a></li>
+  <li class="i2">with air,
+    <a href="#Page_54">54</a></li>
+  <li class="i2">with ether,
+    <a href="#Page_138">138</a></li>
+  <li class="i2">with ethyl chloride,
+    <a href="#Page_128">128</a></li>
+  <li class="i2">nasal,
+    <a href="#Page_57">57</a></li>
+  <li class="i2">physiology of,
+    <a href="#Page_46">46</a></li>
+  <li class="i2">contra-indications to,
+    <a href="#Page_56">56</a></li>
+
+  <li class="i1" id="Nitrous">Nitrous oxide and oxygen,
+    <a href="#Page_8">8</a>,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_60">60</a></li>
+  <li class="i2">various systems for,
+    <a href="#Page_66">66</a>,
+    <a href="#Page_70">70</a>,
+    <a href="#Page_130">130</a></li>
+  <li class="i2">for use in major surgery,
+    <a href="#Page_72">72</a></li>
+  <li class="i2">with ethyl chloride,
+    <a href="#Page_131">131</a></li>
+</ul>
+
+<p class="p-index">O</p> 
+
+<ul>
+  <li class="i1">Obesity,
+    <a href="#Page_158">158</a>,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Obstruction, intestinal,
+    <a href="#Page_141">141</a></li>
+  <li class="i2">respiratory,
+    <a href="#Page_15">15</a>,
+    <a href="#Page_141">141</a></li>
+
+  <li class="i1">Oil ether, Gwathmey’s method of,
+    <a href="#Page_93">93</a></li>
+
+  <li class="i1">Oligæmia in shock,
+    <a href="#Page_10">10</a></li>
+
+  <li class="i1">Omnopon,
+    <a href="#Page_44">44</a></li>
+
+  <li class="i1">Open method, definition of,
+    <a href="#Page_28">28</a></li>
+  <li class="i2">chloroform,
+    <a href="#Page_117">117</a></li>
+  <li class="i2">ether,
+    <a href="#Page_83">83</a></li>
+  <li class="i2">ethyl chloride,
+    <a href="#Page_123">123</a></li>
+
+  <li class="i1">O’Malley’s technique for intra-nasal surgery,
+    <a href="#Page_160">160</a></li>
+
+  <li class="i1">Ormsby’s inhaler,
+    <a href="#Page_81">81</a>,
+    <a href="#Page_137">137</a></li>
+
+  <li class="i1">Over-dosage,
+    <a href="#Page_36">36</a>,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_144">144</a></li>
+  <li class="i2">with nitrous oxide,
+    <a href="#Page_54">54</a></li>
+
+  <li class="i1">Oxygen, reduction in blood in anæsthesia,
+    <a href="#Page_206">206</a></li>
+  <li class="i2">as a relief in asphyxia,
+    <a href="#Page_27">27</a></li>
+  <li class="i2">to old patients,
+    <a href="#Page_165">165</a></li>
+  <li class="i2">with nitrous oxide (<i>see</i> <a href="#Nitrous">Nitrous Oxide and Oxygen</a>)</li>
+  <li class="i2">with nitrous oxide and ethyl chloride,
+    <a href="#Page_130">130</a></li>
+</ul>
+
+<p class="p-index">P</p> 
+
+<ul>
+  <li class="i1">Paralysis, musculo-spiral,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Patella reflex in anæsthesia,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1">Percentages of chloroform and ether required in anæsthesia,
+    <a href="#Page_6">6</a></li>
+  <li class="i2">of chloroform,
+    <a href="#Page_111">111</a></li>
+  <li class="i2">of ether,
+    <a href="#Page_86">86</a>,
+    <a href="#Page_99">99</a>,
+    <a href="#Page_201">201</a>,
+    <a href="#Page_204">204</a></li>
+
+  <li class="i1">Perhalation method, definition of,
+    <a href="#Page_28">28</a></li>
+  <li class="i2">ether (<i>see</i> <a href="#Ether">open Ether</a>)</li>
+
+  <li class="i1">Phenomena of anæsthesia</li>
+  <li class="i2">normal,
+    <a href="#Page_33">33</a></li>
+  <li class="i2">abnormal,
+    <a href="#Page_38">38</a></li>
+  <li class="i2">of nitrous oxide,
+    <a href="#Page_52">52</a></li>
+  <li class="i2">of ethyl chloride,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Pericarditis as a cause of death in anæsthesia,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Phillip’s artificial airway,
+    <a href="#Page_23">23</a>,
+    <a href="#Page_160">160</a></li>
+
+  <li class="i1">Physics of natural respiration,
+    <a href="#Page_96">96</a></li>
+
+  <li class="i1" id="Physiology">Physiology of anæsthetic drugs,
+    <a href="#Page_1">1</a></li>
+  <li class="i2">of asphyxia,
+    <a href="#Page_17">17</a></li>
+  <li class="i2">of chloroform,
+    <a href="#Page_109">109</a></li>
+  <li class="i2">of ether,
+    <a href="#Page_75">75</a></li>
+  <li class="i2">of ethyl chloride,
+    <a href="#Page_122">122</a></li>
+  <li class="i2">of nitrous oxide,
+    <a href="#Page_46">46</a></li>
+
+  <li class="i1">Phthisis,
+    <a href="#Page_167">167</a></li>
+
+  <li class="i1">Pneumonia, post anæsthetic,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Position in anæsthesia,
+    <a href="#Page_157">157</a></li>
+
+  <li class="i1">Positive pressure in nitrous oxide,
+    <a href="#Page_52">52</a></li>
+  <li class="i2">in nitrous oxide and oxygen,
+    <a href="#Page_66">66</a></li>
+
+  <li class="i1">Post-chloroform poisoning,
+    <a href="#Page_153">153</a></li>
+
+  <li class="i1">Post anæsthetic complications,
+    <a href="#Page_150">150</a></li>
+
+  <li class="i1">Pregnancy, anæsthesia in,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Preliminary hypodermic medication,
+    <a href="#Page_11">11</a>,
+    <a href="#Page_43">43</a>,
+    <a href="#Page_152">152</a></li>
+
+  <li class="i1">Preparation of patient,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Primary syncope,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_143">143</a></li>
+
+  <li class="i1">Protection from shock by general anæsthetics,
+    <a href="#Page_8">8</a></li>
+
+  <li class="i1">Pulse, rate in shock,
+    <a href="#Page_6">6</a></li>
+  <li class="i2">clinical observation of,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Pupil, light reflex of,
+    <a href="#Page_32">32</a></li>
+  <li class="i2">size of,
+    <a href="#Page_35">35</a></li>
+  <li class="i2">in asphyxia,
+    <a href="#Page_17">17</a></li>
+
+  <li class="i1">Purging before anæsthetics,
+    <a href="#Page_40">40</a></li>
+</ul>
+
+<p class="p-index">Q</p> 
+
+<ul>
+  <li class="i1">Quinine and urea hydrochloride,
+    <a href="#Page_174">174</a></li>
+</ul>
+ 
+<p class="p-index">R</p>
+
+<ul>
+  <li class="i1">Rebreathing method,
+    <a href="#Page_18">18</a></li>
+  <li class="i2">in nitrous oxide,
+    <a href="#Page_68">68</a></li>
+
+  <li class="i1">Rectal administration of ether,
+    <a href="#Page_93">93</a></li>
+
+  <li class="i1">Rectal saline,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Reflexes as a cause of shock,
+    <a href="#Page_4">4</a>,
+    <a href="#Page_6">6</a></li>
+  <li class="i2">order of disappearance of,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1">Reflex, conjunctival,
+    <a href="#Page_31">31</a>,
+    <a href="#Page_35">35</a></li>
+  <li class="i2">corneal,
+    <a href="#Page_32">32</a>,
+    <a href="#Page_35">35</a></li>
+  <li class="i2">light,
+    <a href="#Page_32">32</a>,
+    <a href="#Page_35">35</a></li>
+  <li class="i2">patella,
+    <a href="#Page_3">3</a></li>
+  <li class="i2">skin,
+    <a href="#Page_37">37</a></li>
+
+  <li class="i1">Reflex syncope,
+    <a href="#Page_8">8</a>,
+    <a href="#Page_112">112</a>,
+    <a href="#Page_145">145</a></li>
+
+  <li class="i1">Regional anæsthesia,
+    <a href="#Page_179">179</a></li>
+
+  <li class="i1">Renal disease,
+    <a href="#Page_163">163</a></li>
+
+  <li class="i1">Rendle’s cone,
+    <a href="#Page_135">135</a></li>
+
+  <li class="i1">Repeated administrations,
+    <a href="#Page_60">60</a>,
+    <a href="#Page_156">156</a></li>
+
+  <li class="i1">Respiration, arrest of,
+    <a href="#Page_142">142</a></li>
+  <li class="i2">artificial,
+    <a href="#Page_146">146</a></li>
+  <li class="i2">blowing,
+    <a href="#Page_34">34</a>,
+    <a href="#Page_89">89</a></li>
+  <li class="i2">crowing,
+    <a href="#Page_16">16</a></li>
+  <li class="i2">depressed,
+    <a href="#Page_39">39</a>,
+    <a href="#Page_43">43</a></li>
+  <li class="i2">effect of morphia and chloroform upon,
+    <a href="#Page_43">43</a>,
+    <a href="#Page_86">86</a></li>
+  <li class="i2">normal,
+    <a href="#Page_34">34</a></li>
+  <li class="i2">obstructed,
+    <a href="#Page_15">15</a>,
+    <a href="#Page_141">141</a>,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Respiration, physics of natural,
+    <a href="#Page_96">96</a></li>
+  <li class="i2">reflex arrest of,
+    <a href="#Page_39">39</a></li>
+
+  <li class="i1">Respiratory abnormalities, minor,
+    <a href="#Page_39">39</a></li>
+  <li class="i2">major,
+    <a href="#Page_141">141</a></li>
+
+  <li class="i1">Respiratory system, effects of ether upon,
+    <a href="#Page_76">76</a></li>
+  <li class="i2">after-effects of anæsthetics upon,
+    <a href="#Page_150">150</a></li>
+
+  <li class="i1">Rigidity of muscles in asphyxia,
+    <a href="#Page_19">19</a>,
+    <a href="#Page_38">38</a>,
+    <a href="#Page_39">39</a></li>
+  <li class="i2">in second stage,
+    <a href="#Page_33">33</a></li>
+</ul>
+
+<p class="p-index">S</p> 
+ 
+<ul>
+  <li class="i1">Saline injections, per rectus,
+    <a href="#Page_42">42</a></li>
+  <li class="i2">subcutaneous,
+    <a href="#Page_14">14</a></li>
+
+  <li class="i1">Schimmelbusch’s mask,
+    <a href="#Page_28">28</a>,
+    <a href="#Page_116">116</a></li>
+
+  <li class="i1">Scopolamine,
+    <a href="#Page_44">44</a>,
+    <a href="#Page_103">103</a></li>
+
+  <li class="i1">Secondary syncope,
+    <a href="#Page_17">17</a>,
+    <a href="#Page_138">138</a>,
+    <a href="#Page_143">143</a></li>
+
+  <li class="i1">Secretion of mucus,
+    <a href="#Page_40">40</a>,
+    <a href="#Page_76">76</a></li>
+  <li class="i2">of urine,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Sedatives,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Selection of anæsthetic,
+    <a href="#Page_162">162</a></li>
+
+  <li class="i1">Semi-open method,
+    <a href="#Page_28">28</a></li>
+
+  <li class="i1">Septic cases,
+    <a href="#Page_9">9</a>,
+    <a href="#Page_60">60</a>,
+    <a href="#Page_156">156</a>,
+    <a href="#Page_168">168</a></li>
+
+  <li class="i1">Sequelæ of anæsthesia,
+    <a href="#Page_100">100</a></li>
+
+  <li class="i1">Sex, relation to anæsthesia,
+    <a href="#Page_165">165</a></li>
+
+  <li class="i1">Shipway, Dr,
+    <a href="#Page_91">91</a>,
+    <a href="#Page_101">101</a></li>
+
+  <li class="i1">Shock,
+    <a href="#Page_5">5</a></li>
+  <li class="i2">difference between syncope and,
+    <a href="#Page_142">142</a></li>
+
+  <li class="i1">Short, Mr Rendle,
+    <a href="#Page_154">154</a></li>
+
+  <li class="i1">Sickness (<i>see</i> <a href="#Vomiting">Vomiting</a>)</li>
+
+  <li class="i1">Sighing,
+    <a href="#Page_40">40</a></li>
+
+  <li class="i1">Sight-feed machines for gas-oxygen,
+    <a href="#Page_70">70</a></li>
+
+  <li class="i1">Signs of anæsthesia,
+    <a href="#Page_36">36</a>,
+    <a href="#Page_53">53</a>,
+    <a href="#Page_65">65</a></li>
+
+  <li class="i1">Silk, Dr J. W.,
+    <a href="#Page_23">23</a>,
+    <a href="#Page_87">87</a></li>
+
+  <li class="i1">Single dose anæsthetics,
+    <a href="#Page_30">30</a>,
+    <a href="#Page_163">163</a></li>
+
+  <li class="i1">Sitting posture,
+    <a href="#Page_21">21</a>,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Slow respiration,
+    <a href="#Page_39">39</a></li>
+
+  <li class="i1">Spasm, muscular,
+    <a href="#Page_19">19</a></li>
+  <li class="i2">of jaw muscles,
+    <a href="#Page_15">15</a></li>
+  <li class="i2">of larynx,
+    <a href="#Page_16">16</a>,
+    <a href="#Page_26">26</a>,
+    <a href="#Page_169">169</a></li>
+
+  <li class="i1">Specific gravity of chloroform,
+    <a href="#Page_109">109</a></li>
+  <li class="i2">of ether,
+    <a href="#Page_74">74</a></li>
+
+  <li class="i1">Spinal anæsthesia,
+    <a href="#Page_193">193</a></li>
+
+  <li class="i1">Stages of anæsthesia,
+    <a href="#Page_31">31</a></li>
+
+  <li class="i1">Starvation, a cause of shock,
+    <a href="#Page_9">9</a></li>
+  <li class="i2">of acidosis,
+    <a href="#Page_155">155</a></li>
+
+  <li class="i1">Status lymphaticus,
+    <a href="#Page_148">148</a></li>
+
+  <li class="i1">Stertor,
+    <a href="#Page_40">40</a>,
+    <a href="#Page_53">53</a></li>
+
+  <li class="i1">Stimuli from field of operations,
+    <a href="#Page_6">6</a></li>
+
+  <li class="i1">Stomach tube, before operation,
+    <a href="#Page_141">141</a></li>
+
+  <li class="i1">Stovaine,
+    <a href="#Page_173">173</a></li>
+
+  <li class="i1">Stridor,
+    <a href="#Page_16">16</a>,
+    <a href="#Page_26">26</a>,
+    <a href="#Page_40">40</a></li>
+
+  <li class="i1" id="Struggling">Struggling,
+    <a href="#Page_34">34</a></li>
+
+  <li class="i1">Strychnine,
+    <a href="#Page_147">147</a></li>
+
+  <li class="i1">Subcutaneous saline,
+    <a href="#Page_14">14</a></li>
+
+  <li class="i1">Swallowing, movements of,
+    <a href="#Page_33">33</a></li>
+
+  <li class="i1">Sylvester’s method of artificial respiration,
+    <a href="#Page_146">146</a></li>
+
+  <li class="i1" id="Syncope">Syncope,
+    <a href="#Page_142">142</a></li>
+
+  <li class="i1">Syringe for local anæsthesia,
+    <a href="#Page_176">176</a></li>
+  <li class="i2">for spinal anæsthesia,
+    <a href="#Page_176">176</a></li>
+</ul>
+
+<p class="p-index">T</p> 
+
+<ul>
+  <li class="i1">Teeth, danger of dropping of into larynx,
+    <a href="#Page_16">16</a></li>
+  <li class="i2">extraction of,
+    <a href="#Page_54">54</a>,
+    <a href="#Page_57">57</a>,
+    <a href="#Page_128">128</a>,
+    <a href="#Page_131">131</a>,
+    <a href="#Page_163">163</a></li>
+
+  <li class="i1">Teter, Dr., on nitrous oxide and oxygen,
+    <a href="#Page_68">68</a></li>
+
+  <li class="i1">Thomson, Prof. Alexis,
+    <a href="#Page_12">12</a>,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Thomson, Torrance, on intratracheal anæsthesia,
+    <a href="#Page_96">96</a></li>
+
+  <li class="i1">Thoracic operations, local anæsthesia in,
+    <a href="#Page_186">186</a></li>
+
+  <li class="i1">Three-way tap for nitrous oxide,
+    <a href="#Page_50">50</a>,
+    <a href="#Page_128">128</a></li>
+
+  <li class="i1">Thyroid gland, <i>see</i> <a href="#Goitre">Goitre</a></li>
+
+  <li class="i1">Time for operations,
+    <a href="#Page_42">42</a></li>
+
+  <li class="i1">Time afforded by single dose anæsthetics,
+    <a href="#Page_163">163</a></li>
+
+  <li class="i1">Tongue falling back of,
+    <a href="#Page_16">16</a></li>
+  <li class="i2">forceps for,
+    <a href="#Page_24">24</a></li>
+  <li class="i2">operations upon,
+    <a href="#Page_97">97</a>,
+    <a href="#Page_118">118</a>,
+    <a href="#Page_166">166</a></li>
+  <li class="i2">local anæsthesia for,
+    <a href="#Page_191">191</a></li>
+
+  <li class="i1">Tonsils and adenoids,
+    <a href="#Page_127">127</a>,
+    <a href="#Page_166">166</a></li>
+
+  <li class="i1">Trachea, mucus in,
+    <a href="#Page_40">40</a></li>
+  <li class="i2">pressure upon,
+    <a href="#Page_17">17</a></li>
+
+  <li class="i1">Trachetomy,
+    <a href="#Page_142">142</a>,
+    <a href="#Page_185">185</a></li>
+
+  <li class="i1">Tremor, ether,
+    <a href="#Page_38">38</a></li>
+
+  <li class="i1">Trendelenberg posture,
+    <a href="#Page_158">158</a></li>
+
+  <li class="i1">Tropacocaine,
+    <a href="#Page_173">173</a></li>
+
+  <li class="i1">Turner, Dr Logan,
+    <a href="#Page_125">125</a></li>
+</ul>
+
+<p class="p-index">U</p> 
+
+<ul>
+  <li class="i1">Urine, secretion of prevented by morphia,
+    <a href="#Page_168">168</a></li>
+</ul> 
+
+<p class="p-index">V</p> 
+
+<ul>
+  <li class="i1">Vagus nerve,
+    <a href="#Page_110">110</a>,
+    <a href="#Page_145">145</a></li>
+
+  <li class="i1">Valved method, features of,
+    <a href="#Page_29">29</a></li>
+
+  <li class="i1">Vapour method, ether,
+    <a href="#Page_90">90</a></li>
+  <li class="i2">ethyl chloride,
+    <a href="#Page_125">125</a></li>
+
+  <li class="i1">Vaso-motor system, in shock,
+    <a href="#Page_9">9</a></li>
+  <li class="i2">in asphyxia,
+    <a href="#Page_17">17</a></li>
+  <li class="i2">in nitrous oxide,
+    <a href="#Page_46">46</a> (and <i>see</i> <a href="#Physiology">Physiology</a>)</li>
+
+  <li class="i1">Veins, large, emptying into heart,
+    <a href="#Page_10">10</a></li>
+  <li class="i2">engorgement of,
+    <a href="#Page_20">20</a>,
+    <a href="#Page_151">151</a></li>
+
+  <li class="i1">Venesection in syncope,
+    <a href="#Page_147">147</a></li>
+
+  <li class="i1">Veronal,
+    <a href="#Page_12">12</a></li>
+
+  <li class="i1">Vicious circle of asphyxia,
+    <a href="#Page_20">20</a></li>
+
+  <li class="i1">Vital medullary centres,
+    <a href="#Page_3">3</a></li>
+
+  <li class="i1" id="Vomiting">Vomiting,
+    <a href="#Page_140">140</a>,
+    <a href="#Page_152">152</a></li>
+  <li class="i2">impending,
+    <a href="#Page_39">39</a>,
+    <a href="#Page_141">141</a></li>
+</ul>
+
+<p class="p-index">W</p> 
+
+<ul>
+  <li class="i1">War, anti-shock, measures in,
+    <a href="#Page_11">11</a></li>
+  <li class="i2">lessons of,
+    <a href="#Page_61">61</a>,
+    <a href="#Page_151">151</a></li>
+
+  <li class="i1">Warming anæsthetic vapours,
+    <a href="#Page_62">62</a>,
+    <a href="#Page_90">90</a>,
+    <a href="#Page_101">101</a></li>
+
+  <li class="i1">Wedge for opening clenched jaws,
+    <a href="#Page_25">25</a></li>
+
+  <li class="i1">Withdrawal of anæsthetic, for stridor,
+    <a href="#Page_26">26</a></li>
+  <li class="i2">for breath holding and struggling,
+    <a href="#Page_34">34</a></li>
+  <li class="i2">for syncope,
+    <a href="#Page_145">145</a></li>
+</ul>
+
+
+<div class="footnotes"><h2>FOOTNOTES:</h2>
+
+<div class="footnote">
+
+<p><a id="Footnote_1" href="#FNanchor_1" class="label">[1]</a> This can be done to a very limited extent indeed if the
+ordinary valves here described are used. <i>See</i> page <a href="#Page_68">68</a>.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_2" href="#FNanchor_2" class="label">[2]</a> A safeguard provided on some machines is a side lead from
+the oxygen supply direct to the facepiece whereby pure oxygen can be
+given if required.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_3" href="#FNanchor_3" class="label">[3]</a> The amount of oxygen in a cylinder is designated in terms
+of cubic feet. A cylinder which would hold 100 gallons of N<sub>2</sub>O, will
+contain 30 cubic feet of oxygen.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_4" href="#FNanchor_4" class="label">[4]</a> In the figure the Clover is shown with gas valves and
+2-gallon bag, arranged for “gas and ether.”</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_5" href="#FNanchor_5" class="label">[5]</a> Trans. xvii. Internat. Med. Cong. Sub-sect. (vii.) Part i.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_6" href="#FNanchor_6" class="label">[6]</a> <i>Journal</i> Amer. Med. Assoc., Sept. 1913.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_7" href="#FNanchor_7" class="label">[7]</a> Trans. xvii., Internat. Med. Cong. Sub-sec. (vii.), Part
+i.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_8" href="#FNanchor_8" class="label">[8]</a> Trans. xvii., Internat. Med. Cong., Sub-sec. (vii.), Part
+ii.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_9" href="#FNanchor_9" class="label">[9]</a> Trans. xvii., Internat. Med. Cong., Sub-sec. (vii.), Part
+I.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_10" href="#FNanchor_10" class="label">[10]</a> The student should be careful to be sure that the bulb is
+attached to the <i>inlet pipe</i>: if by accident it be slipped on to
+the outlet pipe, the first compression of the bulb will eject a stream
+of liquid chloroform from the instrument.</p>
+
+</div>
+
+<div class="footnote">
+
+<p><a id="Footnote_11" href="#FNanchor_11" class="label">[11]</a> The author described this method in a paper read before
+the Scottish Branch of the British Dental Association, and afterwards
+published in the <i>Journal</i> of the Association under the title “The
+Edinburgh System of Dental Anæsthesia.” To the use of this term Dr J.
+H. Gibbs, of Edinburgh, took strong exception in a letter to the Editor
+of the <i>Journal</i>. The author has and had no desire to convey the
+impression that this system was universally used in Edinburgh, but
+simply that it is the method taught by Dr Guy, Dean of the School, to
+the students in the Extraction Room.</p>
+
+</div>
+</div>
+
+
+<p class="transnote">Transcriber’s Notes:<br>
+<br>
+1. Obvious printers’, punctuation and spelling errors have been
+corrected silently.<br>
+<br>
+2. Where hyphenation is in doubt, it has been retained as in the
+original.<br>
+<br>
+3. Some hyphenated and non-hyphenated versions of the same words have
+been retained as in the original.</p>
+
+
+<div style='text-align:center'>*** END OF THE PROJECT GUTENBERG EBOOK 75985 ***</div>
+</body>
+</html>
+
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+This book, including all associated images, markup, improvements,
+metadata, and any other content or labor, has been confirmed to be
+in the PUBLIC DOMAIN IN THE UNITED STATES.
+
+Procedures for determining public domain status are described in
+the "Copyright How-To" at https://www.gutenberg.org.
+
+No investigation has been made concerning possible copyrights in
+jurisdictions other than the United States. Anyone seeking to utilize
+this book outside of the United States should confirm copyright
+status under the laws that apply to them.
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+Project Gutenberg (https://www.gutenberg.org) public repository for
+book #75985 (https://www.gutenberg.org/ebooks/75985)