Cerebral blood flow and metabolism during etomidate anaesthesia in man

The effects of etomidate on regional cerebral blood flow (rc.b.f.) and cerebral metabolic rate for oxygen (CMRo2) were studied in seven patients undergoing diagnostic carotid angiography. Following determination of baseline rc.b.f. while awake, the patients were anaesthetized with a single dose of etomidate 15 mg. Thereafter, an infusion of etomidate (2 or 3 mg min"1) was administered. Etomidate decreased both rc.b.f.,0 (mean decrease 34%) and CMRo2 (mean decrease 45%). It was concluded that etomidate is a potent cerebral metabolic depressant. Furthermore, the cerebrovascular reactivity to carbon dioxide was maintained under etomidate anaesthesia. Etomidate, a carboxylated imidazole derivative, is an i.v. hypnotic introduced in 1971 (Janssen et al., 1971). Since early studies in man (Doenicke et al., 1973), considerable information has accumulated concerning the haemodynamic (Brugmans and Jageneau, 1974