Ether should never be given near an unprotected flame, and lamps or gas-jets should be held above the level of the operating table, as the vapor of ether is heavier than air and will tend to sink. The disadvantages of chloroform where natural gas is in use have already been mentioned.
Efforts should be made to prevent struggling, as in the violence of this unconscious act an overtaxed heart might yield, or at least undergo dilatation. Chloroform is notably less likely to be followed by nausea and vomiting than ether, and yet nausea cannot always be prevented. There can be no doubt that morphine, alone or with atropine, may be given with advantage to most patients before administration of a general anesthetic. The treatment of postanesthetic nausea has been referred to in the chapter on the Preparation and After-care of Patients. By general consent, chloroform is the anesthetic of choice during labor.
THE DANGERS OF AND ACCIDENTS FROM ANESTHETICS.
The principal dangers from any of the volatile anesthetics come from interference with circulation and with respiration. The heart may give rise to alarm by gradual failure in strength, while the pulse becomes more rapid and irregular, or by sudden and apparently complete cessation of activity. When the pupils suddenly dilate and do not react to light danger is close at hand, if it have not already manifested itself, and then is the time to discontinue the anesthetic and resort to vigorous methods, which may include artificial respiration, but must include attention to the heart. It is customary to use injections of strychnine, which are often too weak or too small to be of service, nothing less than ¹⁄₂₀ Gr., which may be repeated in a few moments, will be of any service. If ¹⁄₁₅₀ to ¹⁄₁₀₀ Gr. of atropine be given with the strychnine it will prove a much more effective stimulus. It is right and proper to administer these drugs in this emergency, but still more reliable measures are at hand.
Sudden stoppage of the heart, being the most disastrous accident during or after anesthesia, has attracted no small amount of attention on the part of experimenters. An active massage of the heart seems to furnish the basis for all the newer methods of treating it, all of which are accompanied by artificial respiration. Some of Crile’s work in this connection was alluded to in the chapter on Blood Pressure and Shock.
Fig. 41
Showing how proper traction on the tongue pulls on the epiglottis. (Hare.)
Numerous investigators have revived the hearts of experimental animals by massage and saline injections, and Crile has shown the advantage of adding adrenalin to the latter. It is better to begin the efforts while the heart is still feebly beating than to wait until it has ceased. Ordinarily this massage should be made through the intact thorax, but the time is coming when it will be esteemed life-saving either to open the abdomen and massage the heart through the diaphragm, or to open the thorax and do it directly. The former can be done during almost any abdominal operation. The greatest obstacle to success has been the formation of clots in the cardiac cavities. These are formed within a few moments after the heart has ceased to act.
Massage of the heart, coupled with the use of adrenalin, will prove of service.