Effect of Halothane On Neuromuscular Transmission

The patient with impaired muscle function presents a special problem to the anesthesiologist. At the end of general anesthesia, muscular relaxation must be reversed as quickly and as completely as possible, and for this reason halothane has been a frequent choice as the inhalational anesthetic. Two recent studies¹,²would seem to support this choice since in these experiments the neurally evoked muscle twitch showed no depression during halothane anesthesia. However, in the report by Watland¹it is apparent that the intensity and duration of block by tubocurarine was increased in the presence of halothane anesthesia. Since normal neuromuscular transmission has a reserve safety factor several times that necessary for transmission, a moderate neuromuscular blocking action of halothane might be undetected in twitch tension experiments. This degree of block might be of little consequence under ordinary circumstances, but a moderate blocking action of halothane could be of clinical significance