Intravenous anesthesia in oral surgery

Abstract

T HE two discoveries which probably aided modern surgery the most are the germ theory of disease and the discovery of sulfuric ether as an anesthetic agent. I shall not dwell on the history of inhalation anesthetics, such as ether and nitrous oxide, since every student of the history of dentistry knows the names of Wells and Morton and the r61e dentistry has played in developing these anesthetic agents. I should, however, like to discuss for a few minutes the physiologic action of inhalation anesthetics. According to Cohen-Githens, they may be divided into two classes: (1) the volatile agents including chloroform, ether, ethyl chloride, et cetera, and (2) the gaseous ones such as nitrous oxide, ethylene, and cyclopropane. Those of the first group are inhaled in relatively small amounts in the atmospheric air and derive their narcotic effect from a. chemical action on the nerve cells. Those of the second group are inhaled in much greater concentration, 85 to 95 per cent mixed with but 5 to 15 per cent oxygen. In such concentration they greatly interfere with normal tissue oxidation and are thought to produce anesthesia by asphyxiation of the higher nerve centers. Nevertheless any of the agents in either group when properly administered to patients in whom there are no contraindications for their use, are very satisfactory anesthetics. Because of the frequent contraindications to their use and the expense and training necessary for their safe administration, a third type of anesthesia appeared ; namely, the local anesthetics. Keller’ in 1884 demonstrated the use of cocaine as a local anesthetic. Since then efforts have been made to improve its use along three main lines: (1) to increase the topical effect of the drug, (2) to seek substances safer and less toxic than cocaine, (3) to perfect the manner of its administration. You are all aware of the improvements made in local anesthesia, both in the drugs themselves and in the various techniques of their application. A fourth type of anesthesia has now become available which we will call intravenous anesthesia. This type of anesthesia has long been used in experimental work. It was used in Europe on human patients long before it was taken up in this country. Curiously enough it embraces in part the qualities of both the other types: in that it is a general anesthetic, one whi’ch produces complete narcosis, and in that it is administered in the same fashion as a local anesthetic, by injection, I shall limit my remarks to the use of evipal soluble (Winthrop), a trade name given this particular barbiturate by the manufacturer. There are other similar products on the market equally good. Intravenous evipal soluble is not new in the true sense of the word but is the result of the attempt of research workers to find a quick acting, safe, intravenous anesthetic which also would have a fast recovery. Evipal is a barbituric