Experimental Study on Diethyl Ether Anesthesia

Abstract

Diethyl ether was first described by Valerius Cordus in 1540, and it is generally agreed that Crawford Long used ether for 3 surgical patients in 1842, and Morton subsequently gave a definitive public demonstration in Boston in October, 1846, After this, ether use became widely published and the news spread to London, where Drs. Boot and Squires soon used it on surgical cases at University College Hospital. The importance and volume of diethyl ether in the anesthesia field grew day by day and year by year and it is widely used by various techniques. But, during the past rlecade, the frequency of usage of diethyl ether has declined and it is now hard to find new articles on diethyl ether. The reason is that. the experience of induction is most unpleasant and stormy with secretions, vomiting and laryngospasm; also, excessive depth is often produced and in the post operative course, headache, nausen, vomiting and fluid or electrolyte disorders may follow. Another reason is the production of various new inhalation anesthetics. Today, many serious complications of new anesthetics are reported; especislly halothane may have a hepato-sensitive effect (Burnap 1958, Virtue 1958, Barton 1959, Temple 1962 and Bunker 1963) and new recent articles were published by McArdle (1968), Oyama(1969) and Markello (1969). It should also be remembered that, although its use in clinical practice in Britain and other Western parts is now almost as limited as chloroform, ether is stil1 the main inhalational anesthetic in many parts of the world, because diethyl ether is still an excellent anesthetic safer and perhaps more inexpensive than any other. Since diethyl ether has recently been produced in Korea, objectives qf he study were mainly reevaluation of the effects of diethyl ether through experimental animal studies. Nine healthy normal dogs weighing appoximately 10 kg. body weight were employed in this experiment and 4 dogs (group 1) anesthetized with Squibb ether and 5 dogs (group 2) with Korean made ether, were used for the study. Endotracheal intubation was done under light sedation with pentobarbital sodium 30mg/kg I.V. and the tube connected with a Ruben valve; Nonrebreathing system which could be applied O₂, 0.3 to 0.5 L/min. through the Heidbrink Ohio Chemical Anesthesia Apparatus without any anesthetics. Cannulations were applied into the right jugular vein for C.V.P. into the femoral artery for arterial pressure, the femoral vein for fluid infusion which contained Inulin and B.S.P. (priming doses were 50 mg/kg and 5 mg/kg and maintenance d were 0. 25 mg/kg/min. and, 0.05mg/kg/min) using the Harvard infusion pump (2 ml/min.), the other femoral artery for blood sampling, both ureters for urine collection, and the common bile duct for bile collection. A Polygraph Grass Type 4 Channel Machine was connected for E.E.G., E.C.G., C.V.P. and arterial pressure. During the whole of the study, E.E.G., E.C.G., arterial pressure, C.V.P. and arterial blood sampling for PaCO₂,PaO₂.pH and hemoglobin, and urine collection for Inulin clearance and bile collection for B.S.P. clearence was done every 20 minutes through a 4 hours (one hour for the pre-anesthetic period, two hours for the anesthesia period, and one hour for the post-anesthetic period.). Arterial blood gas, and pH were analyzed with a Radiometer, hemoglobin by the hemophotometer, Inulin clearance by the Schreiner method and B.S.P. clearance by the Pitt aceton method. After the post-anesthetic period, tissue specimens; the heart, lung, liver and kidney, were fixed in 10% formalin and stained with hematoxylin and eosin for histopathological study. Results and Summary An E.C.G. tracing with pulse rate, arterial pressure and C.V.P. were not changed significantly during ether anesthesia in dogs. Within the first 60 minutes during ether anesthesia, PaO₂ were evaluated but after that gradually declined until post-anesthetic period. PaCO₂,pH and hemoglobin values did not show any remarkable change