CHAPTER XX

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ANESTHESIA AND ANESTHETICS, GENERAL AND LOCAL.

To Oliver Wendell Holmes we owe the term _anesthesia_, as generally employed and made to mean insensibility to pain, no matter how produced. A more strict definition would limit the term to conditions comprising not only insensibility to pain but loss of consciousness. For mere loss of sensation we should, strictly speaking, use the word _analgesia_. This is a distinction with a difference. Thus I have on rare occasions seen a patient under chloroform absolutely oblivious to pain but perfectly conscious, and chatting intelligently throughout the operation. This is a rare phenomenon, but has been noted by various observers. So after intraspinal cocaine injections we secure complete analgesia of the lower portion of the body, but not complete anesthesia, the former being what we are most anxious to produce.

The discovery of anesthesia is essentially to America’s credit. Long, of Georgia, had produced anesthesia by ether as early as 1842; Jackson, of Boston, also claims credit for the discovery; but to Morton, a dentist of Boston, is undoubtedly due the honor of having introduced it for surgical purposes. The first public demonstration of its properties was made by Morton and Warren, October 16, 1846, in the Massachusetts General Hospital. Chloroform seems to have been exploited independently by Guthrie, of Sackett’s Harbor, N. Y., and Simpson, of Edinburgh, in 1847. It is a curious historical fact that the patient to whom Simpson meant first to administer chloroform in his clinic did not receive it because of some failure to have it on hand; she took ether instead and died, presumably of the anesthetic. Had she died under the influence of chloroform it would have been a serious setback to any general appreciation of its merits. Nitrous oxide is also an anesthetic for which America may take the credit. These are the three drugs in common use today, although there are others which are coming into general favor.

It can be stated as an axiom that when a surgeon tries to abolish human sensibility, or pass an instrument through the human skin, he introduces elements of danger which can never be certainly and completely controlled--that is to say, the administration of an anesthetic is never to be undertaken as a trifling matter, but should be entered upon as carefully for a minor procedure as for a dangerous and prolonged operation.

Anesthetics are sources of danger, not only for the moment while they are in use, but because of the disturbances which may follow in their train. These drugs should never be administered carelessly nor thoughtlessly, nor by inexperienced individuals, but entrusted to the wisest and the most discreet. More is expected of the anesthetizer than that he shall barely keep the patient alive; he should be so expert as to keep the patient safely on the side of complete anesthesia and muscle relaxation. Nor should he be willing to yield to the importunities of an impatient operator who may be continually appealing to him to crowd the anesthetic. When thus given, and by an expert, such postanesthetic distress as nausea, vomiting, coughing, etc., may be avoided. So generally are these facts now realized and appreciated, that in many of the large hospitals a regular anesthetizer is employed, whose sole duty it is to administer the anesthetic for the attending surgeons. The management of an anesthetic has much to do with the allied subjects of the _preparation of the patient_, the _management of shock or reduced blood pressure_, and the _status lymphaticus_, which have already been considered.

Fatal accidents from anesthetics are the appalling ones which have generally occurred in cases where it has been assumed that the patient is in good condition, and where neither preliminary examination nor preparation has been made. In the presence of unmistakable cardiac disease, or of great arterial tension, the surgeon may, by foreseeing the possibility of trouble, do much to prevent it; but when an apparently healthy individual is placed upon the operating table without attention to these matters it may happen that his heart will stop as suddenly and unexpectedly as though it had been transfixed. In other words, the accidents of anesthesia usually occur when least expected; on the other hand, accidents will be few and far between when all cases are handled as though promising to be severe ones.

The odor of most anesthetics is so distasteful to patients that they inhale at first with difficulty and with signs of irritation. Much of this can be guarded against by spraying the nasopharynx with a 1 or 2 per cent. solution of cocaine. This expedient will make anesthesia much easier for them. The mouth should be examined; all false teeth or foreign bodies, such as pins, chewing-gum, etc., should be removed. Unpleasant burning of the sensitive mucosa of the nose and lips may be avoided by anointing these parts with cold cream. Attention should be given to the avoidance of irritation of the eyes or the careless escape of an anesthetic into the conjunctival sac; with a struggling patient, or a careless administrator, this may easily happen.

Circumstances which would justify the administration of an anesthetic without the consent of the patient, or the friends or parents, occur but rarely; still in an emergency case, with a patient incompetent to decide for himself, the surgeon must assume the responsibility, in which in all probability the law will sustain him.

The anesthetizer should always be accompanied by an assistant; preferably in the case of a female patient, by a female nurse, who may not only be of assistance to him at the time, but an actual protection should the patient experience any erotic delusions during or after her period of anesthesia. This applies equally well to dentists giving nitrous oxide for the extraction of teeth, or physicians attending cases of accident, convulsions, and the like.

The anesthetics in general use are ether and chloroform. If statistics alone are appealed to it can be easily shown that ether is the safer of the two by a large ratio. But the recovery of consciousness by no means indicates the conclusion of the period of danger. The harm which chloroform does is largely done promptly, whereas the unpleasant effect of ether lasts through a much greater period, and the statistics which give ether an advantage are in many respects fallacious. Chloroform is doubtless the stronger and the more subtle agent of the two, and in careless hands would, in all probability, become the more dangerous. _But no anesthetic should be given carelessly_, and no one should give it who cannot give it properly. There may be emergency cases, especially in the rural districts, in which the surgeon may have to act in the capacity of anesthetizer and operator as well, and where he may have to transfer the inhaler to some lay assistant who knows nothing of the action of these drugs. If this happen it would be safer to use ether.

_When administered by a thoroughly competent person_ chloroform is the safer anesthetic of the two, and is usually to be preferred. So largely does the personal equation figure in this consideration that it seems unnecessary to reproduce here statistical tables in regard to its efficiency.

ETHER.

The writer’s intention is to confine his views on anesthesia to the practical application of certain drugs whose chemistry, materia medica, and ordinary therapeutic properties are appropriately treated of in other works.

Ether anesthesia has by some been considered to be simply one form of carbon dioxide poisoning; that it may be all of this, in certain cases, may be granted; but it is certainly something more, as is shown, among other things, by the peculiar odor which persists in the breath of the patient for hours or even for days after its use. Various ways of administering it have been recommended. Some give it well diluted with air, and some give it as strong as a patient can possibly bear it, and from the outset. Some keep mixing air with the vapor, while others have devised inhalers, by which the same ether-ladened air is breathed over and over again. These latter produce a certain degree of the carbon dioxide poisoning above alluded to, and are not ideal even if effective.

Even when well diluted with air the vapor of ether causes irritation of the air passages, in both the nose and throat, and leads quickly to a sensation at first of oppression and then almost of suffocation, which is trying to the self-control of intelligent patients and disturbing to those having little or none. An inhaler saturated with ether should not be pressed tightly over the patient’s face, as it is likely to produce struggling to such an extent that weakened bloodvessels may give way and by their rupture produce serious disturbance.

The first momentary period of irritation having subsided, there will likely follow a few deep inspirations, and then perhaps a fixation and immobility of the chest, so that for half a minute or a minute it would seem as though the patient had _forgotten to breathe_ (Hare). But deep respiration is quickly reëstablished, or may be stimulated by slapping the chest, by a few movements at artificial respiration, or at least by compressing the thorax. Then follows the period of “primary anesthesia,” so called, or a period of excitement, during which the patient may rave or become quite disturbed, and in a manner sometimes quite at variance with his ordinary temperament. As this period subsides the state of complete anesthesia begins, and when muscular relaxation is complete, or even before, the surgeon may commence his work. The respiration under complete anesthesia is usually deeper and sometimes more rapid than in health, while as the muscles become more relaxed a positively stertorous breathing is noted, along with an increase in flow of saliva, due to the irritation of the ether vapor. As anesthesia passes into complete narcosis, and this into asphyxia, the color of the surface, especially of the face, changes to a cyanotic hue, the skin becomes moist and clammy, and the pulse, which had been accelerated, fails. The blood also becomes exceedingly dark from lack of oxygen. Under these circumstances the heart may continue to beat feebly for a short time after respiration has ceased. As Hare puts it: “In producing its effects ether first attacks the perceptive and intellectual cerebral centres, next the sensory side of the spinal cord, next the motor side of the cord, then the medulla, and with this last depression death ensues.”

Ether is more pungent and less agreeable to breathe than chloroform, but the chief advantage usually connected with its use is its supposed factor of safety.

On the other hand, the accidents which are due to ether are in a large measure those common to the use of any anesthetic agent. Among the most prominent is _arrest of respiration_, which may be caused either by mucus or some foreign body in the air passages, or by the tongue dropping back in the pharynx, and the impediment to respiration thereby offered. When the cause of the difficulty is ascertained it is usually easily removed. Should great pallor accompany these symptoms, then, it is usually because the heart as well is at fault, and vigorous stimulation of this organ should be promptly instituted.

Another disadvantage pertaining to ether results from the irritation which its vapor produces in the bronchi and lungs, or in the kidneys during its elimination. From the former may result bronchitis, congestion, or even pneumonia; the latter more often of the catarrhal type than of the croupous. As the result of renal irritation there may be temporary albuminuria, or the congestion resulting may assume so serious a type as to produce absolute suppression (_anuria_), which is practically always fatal. Ether is said to be particularly undesirable in cases of diabetes, because of the resulting acetonuria. Patients have even been known to pass from anesthesia into diabetic coma.

It has been found that complications are more common in males than in females, but more severe in the latter. Vomiting following the use of ether is a frequent and most unpleasant sequel. It is to be prevented by previous lavage, as well as by the same measure at the conclusion of the operation. It will rarely subside when present until the ether vapor has been eliminated. So far as it is possible to suppress it with drugs probably 2 Gm. doses of chloral and one of the bromides, with a little laudanum, given by the rectum in salt solution or a little starch-water, will give the best results.

As already stated, it was formerly held that anesthesia was carbon dioxide poisoning, plus something else which was vaguely described by different authorities; much clearer notions now prevail regarding the mechanism of anesthesia. A few years ago Meyer and Overton concluded that anesthesia is produced by solution of the fatty constituents of the cells by the anesthetic absorbed, this being true at least with chloroform and ether, both of which are solvents of fat. The absorbability of the anesthetic varies with the blood temperature, this varying widely between the cold-blooded and warm-blooded animals. They estimate that 1 part of ether to 400 parts of serum is necessary for complete anesthesia in man, while one part in 4500 to 6000 parts is a sufficient proportion of chloroform. According to these views the dissolved fat is not removed from the cells, and no satisfactory explanation yet accompanies this theory, even assuming its accuracy.

Of no small importance are the experiences of Snel, who found that anesthetics decrease the bactericidal properties both of the blood and of the tissues, but that this power is quickly recovered after the elimination of the anesthetic. He furnishes reason for the theory that the thus lowered resistance of the lungs is an important factor in the production of the pneumonia which occasionally follows operations.

There is a belief that ether is more irritating to the kidneys than chloroform. This, however, does not seem to be justified by evidence, neither is the prejudice against the use of ether during the existence of albuminuria or in the presence of casts. In the presence of a high degree of albuminuria any anesthetic is dangerous, and here ether would be the less desirable of the two. Nevertheless in ordinary mild albuminuria one need not fear to give ether.

About twenty years ago it was suggested that ether anesthesia could be induced by passing its _vapor into the colon through an ordinary rectal tube_. There are many obvious reasons why it would be of great advantage if anesthesia could be safely practised in this way, not only in operations about the face and head, but because of the avoidance of pulmonary and gastric irritation.

The method was to thoroughly empty the colon and then connect a rectal tube with a receptacle containing ether, which was placed in warm water and the vapor passed into the intestine. It was found that patients could be readily anesthetized in this manner, but unfortunately it was also found that a considerable degree of intestinal irritation was produced.

The writer recalls one case in which this method was practised, which terminated fatally within twenty-four hours after the operation, where the autopsy disclosed a violent degree of acute colitis.[7]

[7] _Ether Narcosis by the Rectum._--Cunningham and Lahey have revived the almost abandoned method of rectal ether narcosis, after improving the technique. The rectal tube is introduced for ten to fifteen inches and ether vapor is then forced in until considerable gas is pressed around the rectal tube, keeping the forefinger in the rectum opposite the tube until it causes pain and hastens the expulsion of the rectal gases. It is essential that the rectum be distended to the point of keeping closed around the tube, since unless the gas normally in the bowel be first removed the patient absorbs the ether much more slowly, presumably because of its dilution. At the first introduction of the ether vapor the patient may feel a natural discomfort and desire to defecate, but in a short time this sensation disappears; the breath becomes ether-ladened in from one to five minutes, he becomes drowsy, the breathing stertorous, and he passes into complete surgical narcosis without any excitement.

The apparatus used consists of a bottle seven inches in height, of which five inches are used for ether space and the balance for vapor. The afferent tube which leads to the bottom of the ether ends in a bulb, with small perforations, so that the air escapes in several bubbles. This bottle is placed in a water-bath at a temperature between 80° and 90°. By keeping the ether warm, without boiling, the air forced through it is more easily saturated.

The same care must be given to see that the tongue does not fall over the larynx as when ether is given by the mouth. Should narcosis be too pronounced the tube should be disconnected and ether gas forced out of the bowel by abdominal massage. Oxygen may be given through the same tube if desired, while artificial respiration and stimulation are practised as usual when needed. After completion of the operation the ether vapor should be completely expelled by pressure.

The advantages of the method are that but a small amount of ether is used, there is no stage of excitement, vomiting is rare, bronchial secretion is prevented, and recovery is rapid. It has been shown that six volumes per cent. of ether are required in the blood for the production of complete anesthesia. The rapidity with which the latter can be produced depends upon the rapid production of this percentage. This result is attained more readily by the rectum than by the lungs. For the production of narcosis by this method the rectum should be previously and thoroughly emptied.

CHLOROFORM.

It is important that pure chloroform should be secured for anesthetic purposes. It should be kept in dark bottles, and in the dark, as it is liable to undergo decomposition in the presence of sunlight. It is less volatile than ether, and mixtures of the two drugs are not stabile, since the ether is likely to evaporate first. In its anesthetic effects it resembles ether, acting first upon the perceptive and last upon the motor centres.

The British Chloroform Committee estimate that from 1 to 2 per cent. of chloroform in the inspired air is sufficient for anesthetic purposes, and may be safely used; that 5 per cent. is more than adequate, and that anything stronger than 2.5 per cent. is dangerous.

The _effect of chloroform upon the heart_ is to quicken and then slacken it. The former action is due to a depression of the vagus centre, while subsequent slowing is due partly to vagus stimulation and partly to direct weakening of the heart muscle. While chloroform does not materially affect the excitability either of the vagus or accelerator nerves its main effect is on the strength of the heart

## action, and is less marked on the auricles than on the ventricles.

Ether has a more marked tendency to raise blood pressure than chloroform, while the latter is likely to be more responsible for sudden falls in blood pressure even after its administration has ceased.

The question of the _relative dangers_ of the two drugs has engaged the attention of investigators the world over, and one of the side questions to be discussed is whether chloroform kills by arresting the circulation or the respiration. Chloroform produces a fall in blood pressure (see