The EEG after Etomidate

Abstract

Following the experimental determinations of the hypnotic effect of etomidate in animals and in clinical experiments carried out so far, and on the basis of the available anaesthesiological experience, it seemed justified to test the usefulness of etomidate in combined balanced anaesthesia by further investigations with electroencephalographic control. In our earlier publication (DOENICKE et al., 1973) we described the essential similarity of the course of the EEG stages in etomidate anaesthesias to the stages in barbiturate anaesthesias and determined the tolerance of healthy subjects to an etomidate dose of 0.15 mg/kg. These findings and the observations of other authors now led to questions, which we tried to clarify by means of a clinical experimental investigation. The aim was to establish whether:

• 1. etomidate causes - also in the higher doses required for anaesthesia in adults - EEG stages which correspond to the known stages with other intravenously applied anaesthetics;

• 2. the combination with a premedication of diazepam and fentanyl influences the courses of the EEG and the clinically noticeable signs (especially the motor phenomena);

• 3. the EEG changes together with the clinical symptoms allow any conclusions concerning special action mechanisms of etomidate; and

• 4. any special epileptogenic action of etomidate is detectable.