ETHYL BROMIDE.
For operations of but short duration ethyl bromide offers some advantages, in that its effects quickly pass away and that there are few unpleasant sequels. Indeed, patients may take it for a few minutes with almost as little disturbance as is produced by nitrous oxide; nevertheless it cannot be regarded as being as free from danger as was originally claimed. Only a pure preparation should be used. When given as ether is usually given, upon a cone or mask, complete anesthesia may often be produced within one minute. It can hardly be relied upon to produce muscular relaxation and it frequently causes great congestion of the face and head, consequently it is not as convenient for short operations on the nasopharynx as its other good qualities might render it. It is not unpleasant to take, and ordinary ether anesthesia may well be begun with it.
METHYLENE BICHLORIDE.
For a number of years this anesthetic agent was in favor, especially in Great Britain, where it was warmly advocated by Spencer Wells. Its odor is agreeable, its action rapid, and recovery from its effects is usually prompt. But it proved to be unsafe, since it was found that the substance commonly used under this name was really chloroform diluted with one-fifth of methyl alcohol, while the genuine methylene bichloride was found by experiment to be a dangerous substance, and its use has been discarded.
ETHYL CHLORIDE.
This, like every other drug used for the purpose, should be used in perfectly pure form. While this can be obtained from manufacturers in this country, there seems to be a tendency to rely upon the imported preparation sold here under the name of Kelene. For certain short operations, such as those upon the eye, nose, and throat, and for children, it has many advantages and appears to be a reasonably safe drug for the purpose. Consciousness is quickly recovered after its use, and the after-effects are slight. It is in general use preparatory to one of the stronger anesthetics, like ether or chloroform, and affords a means of putting patients under the relaxing effect of either of these drugs. It should be administered upon a cone or mask, from which evaporation should not occur too easily, because it is extremely volatile. In the hands of one accustomed to its use, operations of considerable magnitude and duration may be successfully maintained. A special valveless mask has been devised for its use, consisting of a rubber mouth-piece which can be snugly fitted to the face, and a movable tube over which two or three layers of gauze may be stretched, upon which the ethyl chloride is allowed to drop or is ejected from the tube in which it is sold. Sometimes the expired air will freeze upon this gauze. This is of no disadvantage.
Local Use.
—On account of its extreme volatility, chloride of ethyl affords a ready means of producing local anesthesia. It boils at 50° F., and when the tube containing it is held in the hands and its capillary tip is opened it issues in the form of a fine spray, which being directed upon the part to be desensitized first chills and then freezes it. Whether this part be skin or mucous membrane the effect is the same. As soon as the desired area is covered with a thin layer of small frozen crystals, looking like hoar-frost, the surface is anesthetized and the necessary instruments may be used. Blowing on the part to be anesthetized will favor evaporation and shorten the time necessary for the purpose.
The purposes to which this drug may thus be used are numerous and obvious. For instance, in dentistry it will do much to allay the pain of tooth extraction; in genito-urinary surgery such operations as incision of the prepuce, the cauterization of venereal ulcers, and circumcision may be done with little or no pain. The small operations required in various skin diseases, the incision of small abscesses, the use of caustics wherever they may be needed, may all be made easy under its effect; while in cases of neuralgia, stings, bites, etc., it will often alleviate the symptoms. The skin may also be anesthetized in this way before the introduction of the needle through which antitoxins are injected or hypodermoclysis practised. Before venesection or before exploratory puncture it may also be used.