Intraoperative electroencephalographic monitoring during carotid surgery with routine shunting.

Fifty-nine patients undergoing sixty-four carotid reconstructions with routine intraluminal shunting had intraoperative electroencephalographic monitoring. The onset of rhythm or amplitude disturbances was demonstrated in 14 patients during exposure of the carotid artery, and in 24 patients during initial carotid clamping. Disturbances were seen in 15 patients during the period of intraluminal shunting and increased momentarily during the second clamping period. During closure of the surgical wound, all abnormalities disappeared except in one patient who ultimately developed a neurologic deficit upon awakening. Although patients who maintained normal electroencephalographic readings had higher carotid stump pressure (59 mm) than those who did not (42 mm), individual values were scattered. Intraoperative monitoring during carotid surgery with routine shunting has little usefulness.