Neuromuscular Effects of Diethyl Ether and Its Interaction with Succinylcholine and d-Tubocurarine

Abstract

The effect of ether inhalation on neuromuscular transmission and the abdominal electromyogram was studied in the cat and in man. In both species, at a time when the abdomen was well relaxed and the electromyographic activity markedly diminished or absent, there was little or no depression of neuromuscular transmission, indicating that the skeletal muscle relaxation seen with ether is attributable mainly to a depression of the central nervous system rather than to impaired neuromuscular transmission. Ether inhalation regularly increased the magnitude and duration of action of succinylcholine and d-tubocurarine in the cat and d-tubocurarine in man. The action of succinylcholine was increased in only 50 per cent of the patients studied. A profound neuromuscular blocking action of ether could only be produced by the close intra-arterial injection of 2-6 ml/kg of 5% ether in the cat. This block was characterized by poorly sustained tetanus and post-tetanic facilitation, but was poorly antagonized by edrophonium or neostigmine.