Thiopentone cerebral protection under EEG control during carotid endarterectomy.

Seventy patients who underwent a total of 77 consecutive carotid endarterectomies were given thiopentone (mean dose 19 mg/kg) under EEG control for cerebral protection during the period of carotid clamping. This technique was used instead of elective insertion of a temporary bypass shunt in response to adverse EEG changes occurring after clamping. The EEG was monitored continuously throughout operation. The EEG burst-suppression pattern with electrically inactive periods of 30-60 seconds was taken as indicating a depth of barbiturate anaesthesia adequate to provide brain protection. Patients exhibited a drop in blood pressure during barbiturate administration: in most the pressure recovered spontaneously but in twenty operations metaraminol was needed to re-establish an adequate pressure before clamping. No adverse cardiological effects were associated with the administration of thiopentone or metaraminol. There was no mortality and no neurological morbidity in this series.