Source:  Snow, John .Med. Times and Gazette, n. s. vol. 14, Mar. 21, 1857, pp. 282-283.

On the recent accident from chloroform

In the case recorded by Mr. Paget, in the Medical Times and Gazette of the 7th inst., the symptoms were observed with unusual care, and described with great clearness; hence the case is one of more than ordinary value, as illustrating the manner in which accidents from chloroform occur. The symptoms in this case were so clear and well marked that they would almost enable us to come to a correct conclusion as to the death if we had no set of exact and systematic experiments on the subject. The chloroform at the moment of the accident was given so as not to interfere with free respiration; the boy had as much air as he could breathe, and did in fact take a long inspiration just when the accident occurred. There was, however, every facility for the air which the patient breathed to be highly charged with vapour of chloroform, as it passed over the lint and cotton wool held half an inch from the face. The effect of the chloroform taken into the lungs by the long inspiration just mentioned was most marked on the action of the heart. According to Mr. Paget's account the pulse, which "had to this time been normal, suddenly began to beat very quickly; then it ceased for two or three seconds; then beat rapidly several times with a kind of flickering movement, and then ceased to be perceptible." Whilst the heart was thus paralysed by the chloroform the brain was not seriously affected by it, for after a few stertorous breathings he breathed naturally for at least a minute, when the respiration began to fail from the want of circulation of blood through the brain.

So much is suggested by a mere reflection on this case, but when it is compared with experiments and observations that I have made on animals there can no longer be any doubt as to the exact cause of death; and I should like to observe that as chloroform produces precisely the same effect on the smaller domestic animals as we daily witness in man, up to a state of complete insensibility, it is very evident that when they are killed by it in such a way that their death resembles exactly the sudden accidents which have happened occasionally to the human species, the cause of death and the conditions under which it occurs must be the same. The strength of the vapour of chloroform which I find most suitable for causing insensibility in patients is about four volumes in one hundred volumes of air; and I ascertained by experiments which I performed some years ago that when animals are made to breathe the vapour of this strength till they are [282/283] killed, death takes place very slowly, the insensibility becomes very profound, with complete relaxation of the voluntary muscles, the breathing becomes embarrassed or very feeble before it ceases, and after it has ceased the heart continues to beat distinctly for a minute or longer, during which interval the creature can easily be restored by artificial respiration. I found, moreover, that at the moment when the heart ceases to beat from over-distention of its right cavities, there is often a deep gasping inspiration, which frequently has the effect of setting about the recovery of the animal if the vapour have been withdrawn.

On the other hand, I ascertained that when animals are made to breathe vapour of chloroform of twice the usual strength or more, that is, of eight or ten parts to one hundred of air, the death is very sudden, taking place in some cases even before insensibility has been induced, and the heart ceases to act, either at the same time as the respiration or before it. These are two distinct modes in which death takes place from chloroform, although with vapour of intermediate strength one mode of dying may more or less encroach on the other.

There is no recorded case of accident from chloroform in the hands of a medical man where the death took place in the first of the above-mentioned modes, as it would do if vapour of the proper strength were continued too long, in the disregard or misconception of gradually approaching dangerous symptoms; in all the recorded cases the death, or at least the fatal symptoms, set in suddenly, generally almost instantaneously, and, in the cases where the pulse was not observed, the sudden pallor or stoppage of bleeding sufficiently indicated that the circulation was arrested. Omitting two cases of fatal syncope, apparently from fear, which have sometimes been attributed to chloroform, there seems to have been ample opportunity in every instance for the vapour to be inhaled in too strong a form, and the result shows that this must have been the case.

In some of the recorded cases of deaths from chloroform the last beat of the pulse was a good as those which preceded it, but more frequently it has been noticed to become very weak just before it ceased. In Mr. Paget's case it beat very rapidly several times, and intermitted for two or three seconds before it finally ceased. In the numerous instances in which I have killed animals quickly with air strongly charged with chloroform, I have generally found the action of the heart to become weak just before it ceased, and in two or three cases, of which I have notes, it beat with extreme rapidity when its action was just on the point of ceasing.

The case under consideration supplies a clear refutation of two of the most serious and prevalent errors respecting chloroform. The first of these is that the patient is safe so long as he has sufficient air for the purposes of respiration; and the second, that close attention to the pulse and the general condition of the patient may of themselves avert danger. Both these rules are right enough, but the present case proves that they will not of themselves avert danger. Indeed the more air the patient breathes the greater is his danger, if the air be too highly charged with the vapour of chloroform; and I have often had occasion to point out the risk arising from a deep inspiration, such as occurred in this case, if the air should contain too much of the vapour. No case could apparently have been more carefully watched than the one under consideration; but the truth is that the first rule to be observed in giving chloroform, is to have the vapour so diluted that it cannot occasion sudden death, and the second rule is, to closely watch every symptom in the patient, so that one may leave off at the right moment, and not produce an unnecessary amount of oppression of the brain, with stertorous or embarrassed breathing.

Mr. Paget says that the quantity of chloroform poured on the cotton wool just before the accident was about forty drops. He probably means a quantity equal to about forty minims, as forty drops of chloroform from a small phial are not quite equal to nine minims; and although that portion of the inhaled chloroform which, by circulating through the coronary arteries, paralyses the heart and causes a sudden accident, must be extremely small, it is not likely that sudden death would occur unless the vapour of several minims of chloroform were to gain access to the lungs in a short time, so as to impregnate the blood passing through these organs very strongly with the agent. The power of chloroform to paralyse the heart by its direct action having been established by experiment,* it can be easily understood how this may occur during the inhalation of strong vapour without the functions of the brain and medulla oblongata being entirely abolished, although their functions cease first when the vapour is slowly introduced; for the coronary arteries being the first given off, the heart must receive its supply of the blood newly arrived from the lungs a little in advance of the brain, and becoming more or less completely paralysed the brain suffers rather from the want of circulation, than from the direct effect of the chloroform. (*"On Narcotism by Inhalation [of vapours]," Med. Times and Gazette, 1848, vol. ii.) In many cases of accident, however, the heart and brain are both overwhelmed by the narcotic vapour at the same moment, as might be expected.

It must be quite obvious that a handkerchief, or cotton wool, or lint can afford no adequate means of properly regulating the amount of vapour in the inspired air, when a patient is to be rendered quite insensible by chloroform; and when Medical men do not take the trouble to use an inhaler, which they have studied with the view to regulating these proportions, they should, as I have several times recommended, dilute the chloroform before using it with an equal measure of spirits of wine. The alcohol is hardly any of it inhaled, but it acts by lowering the tension of the vapour, and diminishing the quantity which is inhaled. For instance, 100 cubic inches of air when saturated at 60º Fahr. with vapour from pure chloroform, takes up 14 cubic inches, and it would be dangerous to inhale it of half this strength; but when the chloroform is diluted with an equal measure of spirit, it will only yield 8 per cent of vapour to the air at 60º, even when fully saturated; practically, it easily yields enough to cause insensibility, but not to cause sudden accident.

There is one opinion, which has many advocates among intelligent Medical men, although it seems to me to be supported neither by facts nor reason. It is, that fear on the part of the patient is a cause of death from chloroform. If this were so, accident might be extremely common; for many patients inhale it, unfortunately, with great fear, only because they have a still greater fear of pain; children, also, are usually afraid of anything so strange, yet accidents have seldom happened to them. Mr. Paget's patient was rendered insensible with safety, notwithstanding his fear, and also a second time after his waking. At the time of the accident he indicated by movements some degree of sensibility, but was not conscious, and therefore could not be under the influence of fear.

If chloroform were forbidden, as some recommend, in cases where the patient is frightened, its employment would be extremely limited, and those who most require it would be entirely deprived of its use. It is, indeed, desirable to try to calm any needless fears the patient may have, for fear is injurious while it lasts; and there are two cases--the one at Mr. Robinson's, and the other at St. George's Hosptial--where the patients died suddenly, before enough chloroform had been inhaled to produce any appreciable effect; but these were not deaths from chloroform; and had the patients lived to come under its influence, their fears would have subsided, and they would probably have been as safe as the thousands who yearly commence to inhale it with great fear. Excessive fear and an overdose of chloroform may either of them cause sudden death, just as infancy and old age both predispose to bronchitis; but they cannot combine to cause an accident in the same case. In fact, as soon as a patient becomes unconscious from chloroform, the effects of fear on the pulse quickly subside.

I have on this occasion, as on all others, thought it my duty to express my views as clearly as I could on the subject of chloroform; but it is not my wish to imply any censure on those, either at home or abroad, who do not agree to my views, or follow the same practice. A commission, which lately sat in Paris, reported that in death from chloroform the breathing always ceases before the action of the heart. It doubtless was so in the experiment they performed; and if, in giving chloroform in what may be called the ordinary way, it always cut off the animal suddenly, in the middle of the experiment, we should be at a loss to understand how it could be exhibited to patients in that way at all. Fatal accidents from chloroform are, however, rare under any circumstances, and a careful consideration of those which are well recorded, like the one under our consideration, as well as experiments on animals, contrived and arranged systematically for the purpose, clearly point out the way in which the accidents occur, and how they may be avoided.

Sackville-street, March, 1857.

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