Source: Snow, John. Lancet 1 (1855): 108-09. [ltr. to ed., January 27, 1855]
Chloroform in London and Edinburgh
To the Editor of the Lancet.
Sir,--I shall be much obliged if you will allow me to make a few brief remarks on the able lecture of Mr. Syme on the subject of chloroform in the Lancet of to-day. I have the happiness to agree with Mr. Syme in the most important points on which he has treated, and if that were all, I should not deem it necessary to address you, for I feel sure that the opinions of this able surgeon would have their due weight, without being endorsed with anything I have to say. It is because I differ from Mr. Syme in some particulars, and because I consider that, in speaking of London as a whole, he has unintentionally done an injustice to certain persons and certain institutions, that I take the liberty of addressing you.
In the first place, however, I wish to state, that I am very much gratified with the remarks of Mr. Syme respecting the disease of the heart. There has been for some time such a strong current of opinion, both in the profession and amongst the public, against the administration of chloroform where there is disease of the heart, that I have been almost deterred from repeating my convictions on the subject so strongly as I could wish, for fear of being thought rash and eccentric, and having my small sphere of usefulness thereby curtailed. If we leave out of view two patients who died suddenly whilst beginning to inhale, and before they could have been affected by the chloroform, and one or two others where the death was most likely unconnected with this agent, I believe that the patients who have died whilst inhaling chloroform have possessed, on the whole, as sound a state of the heart and other vital organs as those who have inhaled it without accident. Persons who require surgical operations are far from being of sound constitution; and this has been especially the case in my own practice, as patients are often sent to me by medical men who hesitate, or decline altogether, to sanction the use or chloroform on their own responsibility. I have found, by very careful observation, that the pain of an operation, disturbs the circulation much more, and puts a feeble heart to a much more severe test than chloroform when carefully administered. I have given chloroform, with the most satisfactory result, to very many patients offering all the symptoms of fatty degeneration of the heart in a very marked degree, as the arcus senilis of the cornea, a feeble, intermitting pulse, and liability to faint. The only patient I have had the misfortune to lose whilst inhaling chloroform, was, indeed, an old gentleman who exhibited the above symptoms in a marked degree. He died as I was proceeding to give a little fresh chloroform, on account of signs of returning sensibility; and I am far from being satisfied that this agent was the cause of his death. The heart was afterwards found to be more degenerated than in many cases where the patient dies suddenly from a very slight shock or exertion, or even without apparent cause.
If the induction of anæsthesia could only be adopted on the strong and robust, it would be a very lame discovery; for persons of feeble or damaged constitution, young children, and the aged and infirm are they who most require to be saved from pain; and, again, if the practice could only be advised for extremely painful operations, the patient would be necessarily impressed with an idea of its essential danger, and the greatest benefit connected with the discovery, that of preventing the anxiety and mental anguish arising from the anticipation of an operation, would be altogether lost.
In speaking of London as a place where deaths from chloroform have occurred, and Edinburgh as a place where they have not, Mr. Syme seems entirely to overlook the relative size and population of the two places. When these circumstances are taken into account, the mortality from this cause seems to be pretty equal. At the time the death in Edinburgh occurred, it rendered the mortality of that place higher than in London, and if another death were unfortunately now to occur in Edinburgh, that place would again have the undesirable pre-eminence. If we are reminded that patients go to Edinburgh from a distance, it must be recollected that private patients come here from the East and West Indies, Canada, and Australia, expressly for operation, and that hospital patients come from nearly all parts of England and Wales. Chloroform is also administered here in certain cases where the Edinburgh surgeons refrain from its use, as in lithotrity and the removal of tumours of the jaw.
If Mr. Syme alludes only to his own department of the Infirmary, he should not contrast that with the whole of London, for there is at least one hospital here, where a great number of operations are performed, and where no such approach to an accident has occurred as those which Mr. Syme speaks of as having happened in his own practice. In King's College Hospital the breathing of the patient never becomes difficult, or ceases, and it has never been necessary to pull out the tongue with the artery forceps. I have seen faintness in a few patients in this institution from loss of blood during the removal of large tumours with extensive vascular connexions, but I have never had reason to be alarmed on account of the effects of the chloroform. The dangers Mr. Syme has incurred have no doubt arisen from his maxim, that "the more rapidly the chloroform is given the better," and I feel certain that under this practice the artery forceps will not always avail to prevent accident. In St. George's Hospital a patient died suddenly whilst beginning to inhale, without being brought under the influence of chloroform, but I believe that there has been no approach to an accident in that institution from the real effects of chloroform. Mr. Syme attributes the supposed greater mortality from chloroform in London to a difference in the mode of its administration, but the real equality in the mortality in the two metropolitan towns is, I think, well explained by the general resemblances of the methods of exhibiting it in both places. In nearly all cases where accidents have happened in London, the Edinburgh method of exhibiting the chloroform was followed pretty closely. If a piece of lint has been used instead of a handkerchief, or the worsted glove of a dresser mentioned in Professor Miller's pamphlet, it was, no doubt, because such a slight deviation was not thought of importance.
It is quite true that in certain quarters too great a reliance has been placed on the state of the pulse in administering chloroform, but that is by no means universally the case in London. Indeed, I have only seen a single case in which the person administering the chloroform seemed to rely for his information chiefly on the pulse. I have never heard of an instance where the chloroform was continued when the breathing was stertorous, although of course such an event might occur in a place as large as London without my knowledge. Usually the inhalation is discontinued here as soon as the common sensibility is abolished, without the breathing being rendered stertorous at all. Mr. Syme says that chloroform is given in Edinburgh according to principle, and in London ac-[108/109] cording to rule. It is my opinion that the rules of some of us here proceed from the principles we have taken great pains to ascertain and establish.
Besides the safety of chloroform when carefully administered, and its applicability in all cases of operation, whether there is chest disease or not, there is one other point on which I agree entirely with Mr. Syme--viz, that the vapour of chloroform should be largely diluted with air. I am a little particular and precise on this point, and say that there should never be less than ninety five parts of air to five parts of vapour. There are two circumstances which I have ascertained to my perfect satisfaction, by very numerous experiments on animals, and what I have observed and heard of the effects of chloroform on the human subject. The first is, that, if air containing not more than five per cent of vapour of chloroform is breathed till the respiration ceases, the heart continues to beat forcibly for some time afterwards. The second is, that, when air containing eight or ten per cent is breathed, it causes a sudden arrest of the action of the heart, by its direct effect on that organ.* (*London Journal of Medicine, 1852.) Now, although death might undoubtedly take place from a person disregarding the symptoms shown by the patient, and continuing the chloroform too long, such an event has not happened, and is not likely to happen, in the hands of medical men. All the accidents have been caused by the direct action on the heart of chloroform not sufficiently diluted with air. The pulse has either ceased before the respiration, or about the same time. If a person who has not experimented carefully with chloroform on animals, nor seen a fatal case of its administration, were to judge entirely by his own observation, he would probably conclude that danger began with the respiration, (because it is in that function that a very slight over-dose manifests its effects when the agent is well diluted with air,) but he would be in error.
The first principle in giving chloroform is to ensure that it shall be very largely diluted with air; but the means recommended by Mr. Syme for this purpose are, in my opinion, insufficient to effect it with certainty. The plan I adopt in practice, is to use an inhaler expressly contrived for insuring a very large admixture of air; but, I have found that many persons allow an apparatus to get out of order, or they are too careless to consider the express purpose for which it was contrived; therefore, if the use of a handkerchief can be rendered safe, it has many advantages. This can be accomplished in midwifery by putting only fifteen minims (equal to sixty-seven drops) on the handkerchief at a time, and waiting till it is used; but, in preparing for a surgical operation, where it is desirable to make the patient quite insensible in about four minutes, it is necessary to use a larger quantity of the agent, and to moisten a greater surface. The proper means to adopt is to dilute the chloroform with spirits of wine. Two parts of spirit and one of chloroform--constituting what Dr. Warren of Boston, United States, calls strong chloric ether--answers very well; but I prefer to use equal parts of chloroform and spirit. The object of the alcohol is not to be inhaled, for it nearly all remains in the handkerchief, but to cause the air to take up less vapour than it otherwise would do. Whilst air is capable of taking up fourteen per cent of vapour from pure chloroform, at 60º Fahr., it can only take up eight per cent from chloroform diluted with an equal measure of spirit; and, in the practice of inhalation, it would rarely take up more than four or five per cent from such a solution, and accidents would be avoided.
It has often been repeated, that chloroform is irritating to the air passages when mixed with spirit; but this is altogether a mistake. When chloroform was first administered in London, in 1847, it was inhaled from its solution, in about seven parts of spirit, under the name of chloric ether. It produced no irritation whatever, and was only left off on account of the uncertainty of its action in such a diluted form, and its expense. Dr. Simpson, as is well known, afterwards introduced its use in the undiluted state; but, except where persons are willing to use a proper apparatus, and take pains with it, it is desirable to return again to a solution of chloroform in spirit, which must be much stronger, however, than that first employed.
I am, Sir, your obedient servant,
John Snow, M.D.
Sackville-street Jan 1855.
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