[Intra-operative EEG surveillance during carotid artery desobliteration]

In 35 patients intraoperative EEG-monitoring during carotid desobliteration under general anesthesia was performed. 15 of these patients had preoperatively focal EEG-changes, coinciding frequently with a cerebral infarct or with carotid changes also contralateral to the side of the desobliteration. 18 patients had during the carotid clamping EEG-changes (slowing of frequency and decrease in amplitude) or a worsening of preoperative changes. 15 of these patients had a complete recovery of these changes after unclamping. The EEG changes do occur more frequent in patients who had a cerebral infarct or bilateral carotid changes preoperatively. Since the EEG-changes during the carotid clamping do signal a critical lowering of the brain perfusion, an ischemic etiology has to be assumed. The use of a shunt during the procedure to prevent irreversible ischemic damage seems therefore to be justified.