Class IV. Ord. V. Diaphoretica.
Class IV. Ord. VI. Diuretica.
Chloroform, or Terchloride of Formyle, is a volatile liquid which is analogous to Ether and Alcohol both in nature and medicinal action, but very different in chemical construction.
Ether = C4H5, O.
Alcohol = C4H5, O+HO.
Chloroform = C2H, Cl3.
A solution of Chloroform in spirit, sold under the names Terchloride of Carbon and Chloric ether, is in very general use, and is employed in very much the same cases as Nitric ether, being in the first place stimulant, and subsequently anodyne, soporific, and diaphoretic.
Chloroform is physiologically an Inebriant. But it is for certain peculiar actions that are coincident with, or immediately follow, this production of inebriation, that it has been so widely and so successfully employed in medicine since its recent discovery. Its two important operations are its anæsthetic effect on sensory nerves, and its paralyzing influence on muscle.
With regard first to the general selection of anæsthetic or anodyne remedies, it is to be observed that there are four distinct kinds of Pain, which differ very much in the treatment required. (1.) Firstly, there is inflammatory pain, caused by an active disease. It is aggravated by pressure; and it has a local cause. For this Opium is the best Neurotic remedy, but it should not be used without an attempt being previously or at the same time made to subdue the active inflammation. (2.) Irritative pain is different. It depends merely on nervous irritation. It also has a local origin; but it is relieved, instead of being aggravated, by a pressure or friction. Such is the pain produced by lead-colic, or by the passage of a gallstone or renal calculus. The pain of Neuralgia is generally of the irritative kind. So is that of Gastrodynia. So also the pain artificially inflicted by the knife in surgical operations. For irritative pain on the surface Aconite is most efficacious. Belladonna comes next to it. In Gastrodynia Hydrocyanic Acid is to be preferred. But to counteract the pain of a surgical operation we require a medicine which shall be capable of producing a powerful effect on the whole system at once. Such medicines are Ether and Chloroform. It is found most convenient to bring the patient under their influence by causing him to inhale the vapour into his lungs. Being absorbed by the pulmonary mucous surface, and passing directly into the circulation, the medicine thus takes effect rapidly. There is no time for the volatile liquid to be excreted from the blood, so that the ulterior effect of the anæsthetic cannot be escaped. The third and most important advantage of this mode of administering Chloroform is that by it we are enabled to regulate with exactness the degree of its action, which is a dangerous one, and to stop it when it has gone far enough. When introduced by inhalation into the general circulation, Chloroform acts upon the brain and sensory nerves throughout the body, so as completely to extinguish their natural sensibility. It is thus an agent of immense value where we wish to save the patient from an extreme and agonizing degree of irritative pain, whether to be caused by the edge of a cutting instrument, or by the throes of parturition. But it also acts as an anæsthetic when applied locally, as to a painful ulcer, or a hollow tooth-stump. (3.) The third kind of pain is reflex in its origin; as the pain in the knee in Hip-joint disease. We should do no good if we troubled ourselves to combat the local symptom in such a case; we should rather direct our attention to that condition which is the distant cause of the pain. (4.) A fourth kind of pain may be called eccentric. Like the last, it does not originate in the painful part. It has its origin in the brain or nervous centres. Of such a kind are the various pains of Hysteria. Local anæsthetics are here worse than useless. The brain disorder must, if possible, be remedied.
Chloroform is better adapted for inhalation than Ether, because it is considerably less irritating. It is, on the whole, very safe, when proper care is taken. And yet it cannot be denied that sudden deaths have occurred from the use of Chloroform, which could not have been avoided by any known precautions. Such an admission tells little against the remedy; for supposing the proportion of deaths from inhalation to be about 1 in 10,000, it must be confessed that it is better that one out of that number should die of the Chloroform than that 100 should die of fright. Out of 9000 cases of its inhalation at St. Bartholomew's Hospital it is reported that not one died of the anæsthetic.
The stages of the action of Chloroform when inhaled may be briefly stated as follows: 1st stage: some alteration in the feelings of the patient; 2d stage: inebriation; the mind and volition are impaired; consciousness remains; 3d stage: unconsciousness; anæsthesia.[48] The loss of sensibility may even occur in the second stage, the patient remaining conscious. The inhalation should not be prolonged beyond the occurrence of the third stage. The pulse is still full. There may be muscular movements, or even cries. In the next stage there is stertorous breathing; the eyelids no longer contract when touched with the finger; the pulse is felt to falter. This is dangerous. To this succeed stoppage of the heart and respiration;—death.
There are four rules which it is safe to follow in the administration of Chloroform; not to go on when there is stertorous breathing; not to administer it when there exists any serious disease of the heart or lungs; not to undertake under its influence an extensive operation on the mouth or jaws; and so to arrange the process as that the vapour shall be freely diluted with air. If the third rule be neglected, the blood may flow into the windpipe and cause suffocation, for the patient is deprived of the power of swallowing. The dilution with air is necessary, not only to moderate the action of the remedy, but that the necessary vital function of respiration may not be interfered with. It is also well known that it is convenient to administer Chloroform on an empty stomach, or it will be likely to produce vomiting.