On chloroform and other anæsthetics: their action and administration

by John Snow

In the use of amylene, absence of pain has been obtained with less profound coma than usually accompanies the employment of chloroform and ether. There are some cases, indeed, in which the minor parts of an operation, under these latter agents, may be performed without pain while the patient is in a semi-conscious state, or even altogether conscious, but they form an exception; while in the use of amylene, the patient has very often been half-conscious during the operation. In operations under chloroform, the patients usually indicate the necessity of repeating the inhalation by a tendency to flinch or cry, without showing any signs of consciousness; but in the use of amylene, they have more frequently begun to look about and to speak before showing any sign of pain. There are some patients who will not lie still under the surgeon’s knife while chloroform is being used, unless its effects are carried so far that the breathing is on the borders of being stertorous, but I have not met with any such case in using amylene.

The greater number of the operations under amylene were performed while the patient was in the second degree of narcotism, being apparently awake, although not really conscious of surrounding objects. This usual absence of coma in the employment of amylene cannot be looked on otherwise than as an advantage. It must conduce to the safety of the agent when the proportion of vapour in the air is properly regulated. The reason why no accident is known to have happened from chloroform, in the practice of midwifery, when superintended by a medical man, is no doubt due to the circumstance that it is only requisite to induce a slight effect, in comparison with the effect required in surgical operations.

The best indication that the patient will quietly bear an operation under chloroform, is the more or less complete absence of sensibility of the ciliary edge of the eyelid; but during the inhalation of amylene the patient is often entirely regardless of the surgeon’s knife, whilst the edges of the eyelids retain their full sensibility, and the slightest touch causes strong winking. In operations on the eye, however, and in all other cases where great steadiness on the part of the patient is required, I have thought it best to continue the amylene till the sensibility of the margin of the eyelids was almost abolished; and to effect this it has usually been requisite to carry the influence of the vapour as far as the beginning of the third degree of narcotism, or that condition in which there is no longer voluntary motion of the eyes, or any other part, and in which the eyelids are usually closed, and the pupils inclined upwards. But even in these cases the patient has usually reverted to the second degree of narcotism before the end of the operation, and has shown signs of ideas by the voluntary motion of the eyes and eyelids, or in some cases by speaking. In several cases, however, the sensibility of the eyelid has been removed in the second degree of narcotism; and important operations have been commenced before the patient was “off”, to use an expression familiar on these occasions. One instance of this kind was the operation of lithotomy by Mr. Fergusson, on the 14th of March, 1857, in a young man, aged 17, in King’s College Hospital. The sound was first introduced, and the stone being detected, the assistants were requested to tie the patient up; and finding his limbs somewhat rigid, they requested me to give him some more vapour. If I had been using chloroform I should have done so without any request, in order to cause relaxation; but I allowed the effect of the amylene to partially subside, and in less than a minute the bandages could be easily applied. I then proceeded to give a little more amylene, but soon found that the margin of the eyelids was insensible; so the operation was performed whilst he was calmly looking about, as if awake; but he showed no sign of pain, and knew nothing of the operation. I never saw a capital operation performed on the adult, under the influence of chloroform or ether, whilst the patient was in this condition; but I once administered chloroform in St. George’s Hospital to a child of three or four years old, which was cut for stone whilst lying calmly with its eyes open, and holding a toy in its hand, all the time of the operation, without letting it fall.

The pulse is almost always increased in frequency and force during the inhalation of amylene,—especially during the early part of the inhalation, and to a greater extent than happens with chloroform. The respiration is very often accelerated during the inhalation,—about as often, I think, as with ether, and more frequently than with chloroform. In many of the early cases in which I administered amylene, the pupil was dilated for a short time; but I consider that this arose from giving the vapour rather stronger than is desirable. I afterwards gave it more gently, and very seldom observed the pupils to be dilated. They remained, as nearly as I could tell, of the natural size, and also sensible to light, in the cases where I made an observation on that point.

The colour of the countenance is generally heightened more or less during the whole period of the inhalation, and in a few cases there was sweating,—a symptom met with now and then under the influence of chloroform and ether. Amylene does not cause the great increase in the flow of saliva which is so often met with during the inhalation of chloroform, and especially of ether.

There is a tendency to laugh during the inhalation of amylene much more frequently than during the use of chloroform. It occurs just after the patient has lost his consciousness, but is soon subdued by the increasing effect of the vapour. I only met with strong mental excitement in a very few patients, chiefly females. It subsided in half a minute in one case, on leaving off the vapour, and did not recur when the inhalation was resumed. In the other cases it was subdued by continuing the inhalation.

The expression of the countenance generally remains calm and cheerful during the action of amylene; but in a few instances there is a singular, and even unpleasant, aspect of the face for a short time, arising apparently from a brief spasmodic action of the muscles.

I met with less rigidity and struggling during the administration of amylene than in the use of chloroform; but this probably arose from the circumstance that the effects of amylene were very frequently not carried to that degree in which rigidity and struggling are liable to appear. It is in the third degree of narcotism from narcotic vapours that rigidity is met with in those cases in which it occurs, but the greater number of the operations under amylene were performed in the second degree of narcotism. The rigidity from amylene, when it occurs, is of a somewhat different kind, and takes place in patients in whom we should not expect it from chloroform. In the spasm and rigidity from the latter agent, the head is more commonly bent forwards or turned to one side, although it is occasionally thrown back; but under amylene, the latter is the usual position it assumes when rigidity occurs, constituting a brief opisthotonos. The rigidity under the influence of chloroform is usually accompanied with struggling, while in that caused by amylene the patient is generally quieter. The persons in whom rigidity and struggling are most violent from the effects of chloroform are lean, muscular men, who work at hard labour, or follow athletic sports, such as hunting, and especially boating; while those who lead a sedentary life, or are reduced by illness, seldom exhibit these phenomena. Women and children seldom exhibit any rigidity under chloroform, and fat persons least of all. Old people do sometimes, especially if thin. Under the use of amylene, on the other hand, I have most frequently met with some amount of rigidity in children and young persons, while many robust men, in whom it would be almost certain to occur under chloroform, have not shown any signs of it. The cause of this probably is, that the operation has generally been performed without carrying the narcotism beyond the second degree, while rigidity does not take place till the third degree is attained. In every case where rigidity and struggling have occurred in the employment of chloroform, however violent these symptoms might be, I have continued the vapour gently and steadily till they were subdued, either by removing the tendency to these symptoms, or by carrying the narcotism to the fourth degree, which is accompanied by relaxation of the voluntary muscular system, and usually with some tendency to stertor. In the use of amylene, on the contrary, I have not attempted to subdue the spasm by continuing the inhalation, but have, with the exception of a case of dislocation previously mentioned, withdrawn the vapour when the rigidity appeared, and the operation has either been performed at once, or else, if it was of a nature that the spasm would interfere with, I have waited a short time, and exhibited a little more vapour very gently, so as to get a state of anæsthesia without the recurrence of the spasm.

Mr. Jones, of Jersey, favoured me with the following account of a case in which amylene acted much more favourably on his patient than chloroform.

John D., æt. 41, stout and of very ruddy complexion, so injured his leg that it was deemed advisable to saw off the fractured ends of the tibia. Chloroform was at first given (March 16, 1857), but the effect it produced, though administered with the utmost caution, was evidently of so dangerous a nature, that it is more than probable that death would have resulted had it been persevered in longer than five or six minutes (the period it was employed). The patient became quite apoplectic, and had two or three very severe convulsions. Amylene was at once substituted, and with the happiest result. The patient appeared conscious, but was not so, and the operation, which was a tedious one, was commenced and finished without his experiencing the least pain, indeed without his having the slightest knowledge that operative measures had been resorted to.