MORPHINE AND SCOPOLAMINE.
Morphine offers no little aid in the production of anesthesia in many cases. Those patients who are terrified by the thought of operation, and who are in a semihysterical state when anesthesia is begun, may be greatly tranquillized by a hypodermic injection of 0.01 to 0.015 of morphine, fifteen or twenty minutes previously. Given in this way it acts as a heart tonic and general equalizer to the circulation. If a small dose of atropine be added the effect upon the respiratory centres is much enhanced. Again, in those cases where anesthesia is begun without it, and patients prove very rebellious, it will have the same happy effect. The only objection to its use is the nausea which may thereby be produced. There is no way by which to dissociate this from the nausea due to the anesthetic, elsewhere considered under the heading of the After-care of Patients.
Patients can rarely be so completely put under the influence of morphine as to justify its use alone.
Scopolamine.
—The Germans sell under this name an alkaloid made from the Solanaceæ, which seems to be identical with the hyoscyamine of the U.S. Pharmacopœia. Schneiderlin, in 1900, published a method of producing anesthesia with little discomfort by using it combined with morphine. The mixture seems more effective than either alkaloid alone, but is rather slow in action. On the day preceding the operation a trial dose of 0.02 of morphine and 0.008 to 0.01 of scopolamine may be given. This will demonstrate the susceptibility of the patient to the mixture. One hour and a half before the operation this dose, or a larger one, should be administered, and, if necessary, another one of smaller size fifteen minutes before the time of operation.
According to this method an interval of sixty to eighty minutes should elapse between the first dose and the operation itself. When anesthesia is thus produced it lasts from three to several hours. Others have advised to divide the dose into three injections, giving the first about two and one-half hours, the second one and one-half hours, and the third one-half hour before operating. In some cases this has produced complete and satisfactory anesthesia; in some it has not been complete, while in others serious symptoms have been produced. The statement that each alkaloid counteracts the dangerous effects of the other is not substantiated; it is probable that the combined effect is greater than would be that of either used alone. This mixture should rarely be used, save in those cases where general anesthesia is inadvisable, and where there are difficulties, even about the employment of local anesthetics.
LOCAL ANESTHESIA.
The use of ethyl chloride, as the most volatile of the ordinary drugs, by which chilling or freezing of the skin may be produced, has been already mentioned. Other agents which chill or freeze may be used, e. g., a spray of common ether or of rhigolene, or the local application of ice and salt.
Liquid Air.
—Liquid air, when available, affords an excellent means of benumbing sensibility, since one or two very light applications, two or three minutes apart, admirably serve the purpose. It is, however, rarely available and should be used with great caution.