Total intravenous anesthesia with etomidate. III. Some observations in adults.

An investigation was undertaken to determine the dosage of etomidate required to maintain sleep in adults undergoing surgery under regional local anesthesia. Premedication of diazepam 10 mg and atropine 0.5 mg was given, and sleep was induced and maintained by intermittent intravenous injections of etomidate 0.1/mg/kg, given whenever the patient would open his eyes on request. A mean overall dose of etomidate 17.4 microgram/kg/min. was required to maintain sleep, but great individual variation occurred, with older patients requiring less drug. The investigation was discontinued after 18 patients because of the frequency and intensity of side-effects, particularly pain and myoclonia, which caused the technique to be abandoned in two cases. It is considered unlikely that etomidate will prove to be the hypnotic of choice for a totally intravenous anesthetic technique in adults because of the high incidence of myoclonia after prolonged administration. In several patients uncontrollable muscle movements persisted for many minutes after complete recovery of consciousness.