Practical anaesthetics

Preface

The object of this little book is to furnish a short guide to those who have not the leisure to study such valuable works as Dr. Hewitt's Ancesthetics and their Administration and Mr. Gill's CHCl^ Problem.

I have endeavoured to treat the administration of anaesthetics from a practical point of view alone, and to enumerate the rules which, from my experience of teaching, I have found to be most valuable for the guidance of the student.

The Theory and Physiology of Anaesthesia have only been mentioned briefly when they have a direct bearing on important details of practice.

I am very much indebted to Mr. Richard Gill for his practical teaching in the past, and also to Dr. F. W. Hewitt for the free use I have made of his recent writings.

I have not thought it necessary in so small a vi PREFACE

volume to give a list of references to all my authorities.

I have to thank Messrs. Barth & Co., Arnold & Sons, Duncan Flockhart & Co., and Down Bros., for the loan of blocks, and E. Bridle for taking photographs.

Lastly my best thanks are due to my friend and colleague, Mr. R. B. Etherington-Smith, for much valuable advice and assistance in the preparation of these pages for the press.

Chapter I

Before describing the various methods by which general anaesthesia may be induced, it is advisable to define the term " anaesthesia," and to consider some of the general duties of the administrator.

Ansesthesia.

The condition of general anaesthesia is one in which there is : —

1. Insensibility to pain.

2. Unconsciousness.

3. Diminished reflex action.

4. Absence of movements of the voluntary

muscles.

Duties of the Anaesthetist.

The first and most important duty of the administrator of the anaesthetic is absolute attention to his case. He must not allow himself to be distracted by events occurring outside his own sphere of action ; if he does so, he wiU find that it is impossible to observe the many phenomena of anaesthesia, and that the time for action, signalled as it were by these phenomena, may have passed before he has discovered that something must be done. It is not meant by this that the anaesthetist should be ignorant of what is being done by the surgeon — his knowledge of the progress of the operation will often modify his method of administration : but he must be carefully on his guard against becoming absorbed in watching the operation, and so forgetting his patient. I know of no better advice to a man beginning the study of anaesthetics than this : — Keep your whole attention on what you are doing, and do not aUow outside influences to interfere with your own work.

The anaesthetist must remember that he holds the life of every one of his patients in his hand. Consequently, if at some critical moment he be found flurried and at a loss what to do, the result may be disastrous. In this branch of the profession, perhaps more than in any other, promptness and rapidity of action; a cool head and a steady hand are most essential.

Examination of Patients.

A drawback under which the ansesthetist labours is that as a rule he is called upon to administer an anaesthetic to a patient of whom he has no previous knowledge. The patient's general habits of life, whether or no he is a heavy drinker or smoker, has suffered from any pulmonary, cardiac or renal disease, diabetes and the like, all these are points which should be known before the anaesthetic is administered. The surgeon who has charge of the case will usually be in a position to supply this necessary information, but, if not, the more important details can be ascertained by a few leading questions, and the heart and lungs can be examined. The latter precaution should not be neglected, for apart from the fact that it enables the anaesthetist to reassure the patient as to his fitness to take an anaesthetic, it also provides against having to confess ignorance of the condition of the chest should an accident occur.

Before beginning the administration of any anaesthetic it is advisable to ascertain how the patient breathes : he may have nasal or laryngeal obstruction, and it is a good plan, therefore, to make him take one or two deep breaths and to observe any such abnormality. It is, of course, obvious that should there be nasal obstruction, the mouth must be kept open during the operation ; should there be laryngeal obstruction, tracheotomy instruments must be close at hand.

Inquiries should next be made as to artificial teeth, and if present they must be removed : they are a source of grave danger, the most dangerous kind being the small plate with one or two teeth which can easily fall back and obstruct the larynx.

Closely fitting teeth frequently cause trouble to the anaesthetist, if he has not taken the precaution of inserting a dental prop or the corner of a towel before starting the administration. Trouble may also arise with edentulous people from the lips falling in, but this is easily_overcome by placing the end of a fine towel in the mouth. This serves two purposes : —

1. It keeps the lips apart and allows air to enter

freely.

2. It soaks up saliva and mucus.

Fear of the Anaesthetic.

Fear of an anaesthetic is a very real factor, and probably accounts for more deaths than is commonly supposed. There are many patients to whom the taking of an anaesthetic is a much dreaded ordeal ; they not only have a deeply rooted fear of it, but also are firmly convinced that they will die under it. It is with such patients that some of the fatalities of anaesthesia occur. It must be remembered that many people have sufficient selfcontrol to enable them to outwardly conceal their fear. Therefore nothing must be done which might startle a patient, and if he is obviously frightened every effort should be made to reassure him. In every case, whether or no the patient be nervous, there should be absolute quiet in the room during the induction period. Talking, moving about, opening and shutting of doors, preparation of instruments and lotions — all these should be forbidden until the patient is unconscious. It is sometimes wise to allow a nervous patient to hold the hand of a nurse or friend untU anaesthesia is complete ; this may help to reassure him. But, with this possible exception it is most important that the patient should not be touched or addressed by any one but the administrator. It is only too common to find the doctor or nurse feeling the pulse, talking to the patient, raising and dropping the arm, and so on ; such interference should not be permitted. The reason for taking these precautions is that before consciousness is lost sounds and actions are perceived by the patient in a much magnified form — they tend to alarm him, and to interfere not only with a tranquil induction period, but also with the subsequent maintenance of good anaesthesia.

Preparation of the Patient.

Whenever an anaesthetic is to be given it is desirable that the patient should be properly prepared beforehand. It may not always be possible to carry this out, but as careful an attention as occasion permits should be paid to the preparation.

For an ordinary operation, such as a radical cure of hernia or excision of glands in the neck, the best course is to give a purgative (01. Ricini gss.) twentyfour hours before the time fixed for the operation, and if necessary a second dose twelve hours later, A soap and water enema may also be given with advantage a few hours beforehand. If the operation is to take place at 9 a.m., which is the best time for the purpose, no solid food must be given after the evening meal, and that should be a light one. A small cup of beef-tea at 6 a.m. is all that should be allowed, and this can usually be dispensed with. For operations later in the day — e.g. 1.30 p.m. — the patient may take a light breakfast at 7 a.m., and nothing more, except perhaps a cup of beef -tea at 10 a.m. Patients prepared in this way are found to take the anaesthetic better, more safely, and with less unpleasant after effects than those who have not been so treated.

For some operations, such as those on the rectum, a more thorough preparation is necessary ; but this matter is in the surgeon's province, and need not be detailed here.

In every case care must be taken to keep the patient warm during the operation. For this purpose long woollen stockings and other warm clothing should always be employed in so far as the site of the operation permits. The table should be well warmed, and where there is no water-jacket for this purpose, hot water bottles can be utilized.

The temperature of the operating theatre must be kept up to 70° F., and in many cases considerably over this point : it is important that adequate ventilation be ensured as well as warmth of the atmosphere.

Apparatus.

In addition to the actual apparatus required for the administration of the anaesthetic, the anaesthetist should always have at hand : —

1. Two mouth-props (Fig. 1).

2. A Mason's gag — that pattern in which the

blades fall one behind the other when closed

Fig. 1. — Mouth-props.

Fig. 2.— Mason's Gag.

Fig. 3. — Tongue Forceps.

is the best, being the easiest to place in position (Fig. 2). 3. Tongue forceps (Fig. 3).

Fig. 4. — Tracheotomy Case.

4. A wooden wedge.

5. Hypodermic syringe, and a bottle of Liq.

Strych. Hydrochlor.

6. Tracheotomy case (Fig. 4).

7. Two sponge holders, and some small marine

sponges.

Fig. 5.— Mr. G. H. Colt's Gag.

This figure depicts a new gag made by Messrs. Down Bros, to the directions of Mr. G. H. Colt, senior resident anaesthetist at St. Bartholomew's Hospital. The chief points claimed for this gag by Mr. Colt are as follows : — ■

1. It has been constructed on scientific lines, in that the

various measurements have been carefully worked out from observations taken on 500 patients.

2. The weight of the gag is only 4|^ ounces, whilst the strength

and rigidity have not been diminished.

3. The length is 6^- inches, this being the maximum that per-

mits the gag to be used for a child without the handles touching the pillow.

4. The tooth plates are of the overlapping variety, and are

specially designed to prevent them from slipping when in position ; moreover they are sufficiently short to be out of the surgeon's way in cases of tonsillotomy.

5. The anaesthetic tube can be easily placed in any desired

position, and is made of malleable metal.

Position.

The position of the patient will be regulated in the main by the surgeon : the anaesthetist must learn to accommodate himself to the one chosen. The sitting position for dental, some intra-oral and nasal operations, the lateral, semiprone, prone, lithotomy and Trendelenburg positions — all these will receive special mention in subsequent chapters. In the majority of cases, the sitting position excepted, anaesthesia is induced with the patient in the dorsal decubitus, the required change being made subsequently. The patient should be allowed to lie as comfortably as possible and not forced into any strained attitude, but the pUlow beneath the head should be a smaU one. In the case of ether administrations, it is well to direct the patient to turn the head to one side, preferably to the right : this makes the application and holding of the face-piece more easy, allows excess of saliva and mucus to run out of the mouth, or at least to collect in the cheek, and to some extent prevents the falling back of the jaw and tongue. Gas, gas and ether, gas and oxygen, or ethyl chloride may be given in the sitting position. Chloroform, or any mixture containing chloroform, must never be used to induce or maintain ansesthesia while the patient is sitting ; such a proceeding is highly dangerous. It may sometimes be necessary to raise up a patient who has been already anaesthetised. This is permissible, unless chloroform has been employed, but the recumbent position should always be resumed as speedily as possible.

The Moving of Anaesthetised Patients.

The anaesthetist may be called upon to give an anaesthetic to a patient lying in bed. He should never do so unless there are good reasons against placing the un-anaesthetised patient upon the operating table.

None of the difficulties that may arise in the course of the administration can be so promptly or efficiently dealt with as when the patient is on the table. The width of the bed, the flexibility of the mattress, and the rails at the head and foot, are all serious impediments to the anaesthetist when danger threatens.

When the induction has to be undertaken with the patient in bed, he should not be removed to the operating table before the stage of true anaesthesia has been reached. Such moving of patients, although it is a very general practice, is not to be recommended, particularly when chloroform is being employed. It carries with it a risk of syncope. If it has to be undertaken, it is better that the patient should be completely anaesthetised, and no departure from the horizontal position must be allowed.

After Treatment.

The duties of the anaesthetist do not end with the application of the dressings at the close of the operation. In hospital practice, it is true, a competent nurse takes charge of the patient when he has been removed from the table, but the anaesthetist should be prepared to give her any special warnings or instructions that may be required. In private practice, moreover, he should supervise the carrying of the patient to bed. The^atient should not be transferred to the stretcher until some signs of returning consciousness are manifested— presence of the corneal reflex, swallowing movements, etc. He should be lifted gently with as little alteration as possible from the horizontal position. The stretcher should be carried feet first if any steps or slope have to be ascended, so that the patient's head may never be suddenly raised. This is a most important item, neglect of which may lead to fatal syncope. The patient is carefully placed in a bed previously well warmed, and containing suitable hot water bottles. The head should not be raised, and in cases of collapse should be considerably lowered by placing blocks under the foot of the bed.

In all cases where the nature of the operation and the condition of the patient admit of it, he should be placed on his side. This causes a more rapid recovery from the anaesthetic, diminishes the tendency of the tongue and mandible to fall back, renders the action of vomiting more easy and less violent, and almost abolishes the danger pi vomited matter entering the larynx. When for any reason the lateral position cannot be employed, the patient's head should at aU events be turned to one side. During the removal of the patient to bed the anaesthetist should take charge of the head, watch carefully the character of the respirations and for the onset of vomiting, and act accordingly. He should not leave the bedside until he is satisfied that, so far as the immediate effects of the anaesthetic are concerned, his patient is safe. The after-treatment of nitrous-oxide cases requires little mention : as a rule the patient recovers consciousness almost immediately, and feels no ill effects. Hs should be allowed to remain in the chair for five or ten minutes, and after resting quietly for a quarter of an hour may usually be allowed to get up or go home. In very rare instances the recovery from gas is much prolonged, and vomiting may occur.

The Vomiting that occurs after the use of other anaesthetics varies considerably in different cases. The varieties are due to several factors, among which the principal are : —

1. The patient.

2. The ansesthetic employed.

3. The administration.

4. The preparation.

Some patients will vomit violently and for many hours after ether, chloroform, or A.C.E. mixture, in spite of the exercise of great care and skill on the part of the anaesthetist : others are found to have a particular idiosyncrasy to one of these drugs but not to the rest : others again never vomit, no matter what the anaesthetic, nor how long its administration. The last-mentioned individuals are for the most part alcoholics, or strong young men in good condition. After an administration of ether the patient usually vomits early — before he has completely recovered consciousness. The vomit consists of bile-stained fluid from the stomach, together with saliva and mucus that have been swallowed. Vomiting is more likely to occur after ether than after chloroform, but in the former case it is not usually prolonged. In fact the early vomiting that occurs before the patient has recovered consciousness may be the only manifestation of this sequela. Prolonged ether is more likely to cause vomiting than a short ansesthetic, more especially if the administration has not been skilfully managed and cyanosis has been allowed to occur.

Chloroform properly given is not so frequent a cause of vomiting as ether. The vomiting, moreover, begins later, but it may continue for many hours. This prolonged vomiting that occasionally follows chloroform anaesthesia is most distressing to the patient and extremely difficult to combat. The administration of ethyl chloride is not infrequently followed by vomiting, and this fact alone makes nitrous oxide a more suitable anaesthetic for dental and similar work.

The manner in which the patient has been previously prepared is a most important factor. Should food have been taken a few hours before the operation, and the rules for preparatory treatment neglected, copious vomiting is almost certain to follow. The different anaesthetics may be classified according to the relative frequency with'which they are followed by vomiting.

The order is as follows : —

1. Nitrous oxide (very rarely causing vomiting).

3. Chloroform and mixtures containing chloro-

form.

The prevention of vomiting is aimed at by attending to the proper preparation of the patient and by careful administration. The turning of the patient's head to one side, by allowing the mucus and saliva to run out, lessens the tendency to vomit which is induced by the swallowing of these secretions. Furthermore, a prolonged or badly given ether administration will cause much salivation, etc., and so increase the subsequent vomiting. In such a case as the last, however, the vomiting is of much benefit to the patient by clearing away the mucus from the air passages and the fluids from the stomach. The treatment of this sequela is usually confined to withholding food for about three hours, and giving small pieces of ice to suck or drachms of hot water to drink. The early vomiting that occurs, especially after ether, is advantageous rather than otherwise and causes no distress, as it comes on before the patient has recovered consciousness. It is the persistent vomiting that requires treatment and is so difficult to check. Teaspoonfuls of very hot water will be found, as a rule, of more service than ice to suck. If a drink of several ounces of water is given, it will cause vomiting ; the fluid should therefore be confined to sips under ordinary circumstances. If, however, vomiting continues unabated and becomes distressing, it is often a good plan to allow the patient to drink six or ten ounces of water. This will be returned in a few minutes, but may check the continuance of the vomiting, for it acts by washing out the stomach to some extent. It may occasionally be advisable to wash out the stomach thoroughly by passing an oesophageal tube, but it is better practice to make trial of the simpler, less disturbing and unpleasant method before proceeding to this remedy. Instead of giving plain water sodium bicarbonate (grs. xv. to the ounce) may be dissolved in it with advantage. Many other remedies have been and are employed, but cases should be treated, broadly speaking, on the same lines that are followed for vomiting from other causes.

The administrator will find that as his skill and experience increase with practice, so will his cases of vomiting after the anaesthetic diminish. He should make it a rule to find out as far as possible what the sequelae of every anaesthetic have been : he will thus add a considerable store to his knowledge, and to his judgment in selecting the anaesthetic best suited for the case and for the occasion.

Shock and Collapse.

It is not proposed to discuss here at length the causes or varieties of shock which may occur during anaesthesia as the result of the operation.

It is well, however, to distinguish between two conditions, either of which may arise during or after the administration.

I shall apply the terms " shock " and " collapse " in referring to these different states.

Shock of some degree follows most injuries and surgical procedures. It is not usually obvious, but is recorded on the temperature chart. The slight fall of temperature for the few hours following the operation and the subsequent reactionary rise above the normal, may be observed in nearly every uncomplicated case, even though there have been no other symptoms. The shock is to be regarded as reflex in origin, dependent upon, and directly proportional to, the injury sustained by the nervous system. The shock which accompanies cutaneous burns in children is of the same nature, and its degree is proportional to the area of cutaneous nerve distribution involved. We should expect that the use of anaesthetics would diminish the extent of operative shock : this is probably the case. Nevertheless, it would seem that when in a semi-ansesthetised condition the patient is even more susceptible to shock than when not anaesthetised at all. It is not remarkable that the reflex mechanism of shock should be more in evidence under these circumstances, but the fact has a most important bearing on the administration. It is a dangerous practice to permit the surgeon to make his first incision before true surgical anaesthesia has been induced ; moreover, for certain operations such as cholecystectomy, nephrectomy, pylorectomy and the like, in which the great sympathetic plexuses are liable to be disturbed, a deep degree of anaesthesia is safer for the patient than a light one. If the patient is insufficiently under the influence of the anaesthetic, the shock consequent upon the first incision or subsequent manipulations may reflexly produce inhibition of the cardiac or respiratory mechanisms, or of both together.

For certain operations a very light anaesthesia is required — operations on the thyroid gland come into this category. Even in these it is wise to induce anaesthesia in the ordinary manner, and to allow some relaxation of its depth as soon as the operation has begun. The risk of fatal shock at the first incision is thus obviated. At other times the patient's general condition, dyspnoea, or other embarrassment, forbids the induction of true surgical anaesthesia ; in such cases the risks of shock are far less grave than those of anaesthesia and are outweighed. It has already been pointed out that an inconspicuous degree of shock is attendant on all surgical procedures and requires no special attention. Severe surgical shock, on the other hand, may produce a state of collapse. The shock may affect primarily either the respiratory or the circulatory system — more frequently the former : in severe cases both will be eventually implicated. The reflex mechanism alluded to above produces laryngeal spasm, which, if unrelieved, must terminate in failure of the respiratory centre, and secondarily of the circulatory mechanism also. The commencement of the operation before anaesthesia is complete may affect the circulation as well as the respiration. Though fortunately not so common, the result is more serious, namely cardiac arrest from reflex inhibition. The circulatory changes that may occur as the result of the administration of an anaesthetic are, with this exception, confined to the stage of deep anaesthesia. Furthermore, they are seldom, if ever, encountered except when chloroform is used.

Chloroform causes a fall in blood-pressure owing to its toxic effect upon and the consequent dilatation of, the vascular musculature. Physiological experiments have shown that circulatory disturbance can be produced by nerve stimulation. The first effect of stimulation of sensory nerves is usually one of vaso-constriction and rise of blood-pressure, but it is found that after a time the reverse effect is produced, the pressor fibres being more readily exhausted than the depressor. Moreover, the depressor fibres can be excited from the first by the use of mechanical and special stimuli.

Now in deep chloroform anaesthesia with its already low blood-pressure, a depressor effect will produce a far more marked result upon the general circulation than if the blood-pressure had been normal to begin with.

This is still further intensified by the toxic properties of chloroform, which hinder the heart from accommodating itself to sudden alterations in blood-pressure. A fall in blood-pressure may be produced either by paralysis of the vaso-constrictor centre from the direct action of chloroform upon it, or as a reflex depressor effect, due to surgical stimuli.

It follows from these facts that shock may be manifested during deep chloroform anaesthesia through circulatory disturbance — herein lies the main danger of chloroform overdose.

The condition of shock, if severe, leads to that of Collapse. In the latter the patient is pale, with small, frequent, perhaps imperceptible pulse. The extremities are cold, the pupils dilated, the eyelids half-closed. There is cold, clammy perspiration and shallow breathing.

Collapse is usually due to the serious nature of the operation, to loss of blood, or to the previously debilitated state of the patient, which renders him unfit to withstand the shock. It is not often a direct result of the anaesthetic ; but it has been pointed out above that it may be consequent upon too light an anaesthesia, or upon a full dose — probably always an over -dose — of chloroform.

The treatment of severe surgical shock and collapse is as follows : —

1. The anaesthetic must be discontinued if this is stni being administered.

c3 .

II

2. The head must be lowered and the feet raised.

Children may be held up by the feet. Paralysis of the respiratory centre, from - anaemia secondary to, circulatory failure, may be overcome by this means.

3. A hypodermic injection of strychnine (gr. J^-)

should be given.

4. Brandy may be administered.

5. An injection of normal saline solution per

rectum or intravenously is especially valuable in cases of collapse due to haemorrhage.

6. Warm cloths should be applied to the

abdomen, chest and head, and hot bottles to the feet.

7. Auto-transfusion, i.e. bandaging of the legs

and arms from below upwards, may be employed.

Artificial Respiration.

Silvester's Method. — When artificial respiration is necessary, the mouth must first be opened by a gag and the tongue drawn forwards by tongue forceps. The patient is then puUed up the table, so that the head hangs over the end in a fully extended position.

The lower end of the table should at the same time be raised. The anaesthetist must hold the gag in position and continue to exert traction on the tongue, while an assistant or the surgeon performs artificial respiration. The person who undertakes this task stands behind the patient's head, and grasps the arms just above the elbows. He presses the arms firmly against the chest and continues the pressure for one or two seconds. He then lifts the arms and extends them fully beyond the head. After maintaining this position for about two seconds he again brings the arms to the sides and exerts pressure as before.

The extension of the arms causes air to enter the lungs by increasing the diameter of the chest : the pressure of the arms against the sides expels air from the lungs.

Artificial inspiration and expiration are thus effected, but the movements must not be hurried. They should not be repeated more than twelve or fourteen times a minute, otherwise sufficient time will not be given for the full entry and exit of air.

Other methods of performing artificial respiration are employed, but Silvester's is probably the most effective. Simple compression of the chest at intervals may, however, be found usefuL It is performed by standing in front, or better still by kneeling on the table astride of the patient. The outstretched hands are placed on either side of the chest over the lower ribs and the costal arch, so that the two thumbs are over the xiphisternum. The chest is forcibly compressed for two seconds and then suddenly released. The pressure is applied about twelve times a minute.

This last method may be userul in certain cases of cerebral abscess. In such it may be necessary to continue artificial respiration while the surgeon is removing the cause of the respiratory failure by evacuating the abscess.

CHAPTER II Apparatus

The apparatus necessary for the administration of nitrous oxide consists of one or two cylinders, footkey, stand, union, indiarubber tube, indiarubber bag, valved stop-cock and face piece. The accompanying illustration shows how these are connected together. The manufacturers supply gas compressed in cylinders of 25, 50 and 100 gallons capacity ; the small size, being more portable, is the most convenient for private practice, the large size is best suited for hospital work. It is always advisable to use two cylinders connected together by a double union, as shown in the illustration, in case one should fail. The indiarubber bag should have a capacity of about two gallons and is connected to the face-piece by the valved stop-cock. There are various patterns of stop-cock, the one illustrated being simple and efficient. When the lever is in position A, the patient is breathing pure air through the aperture ; when the lever is moved to position