Intraoperative use of electroencephalography as an assessment of cerebral blood flow.

The electroencephalogram (EEG) is exquisitely sensitive to decreases in cerebral blood flow (CBF). The EEG can detect cerebral ischemia in the awake and generally anesthetized patient. EEG monitoring of CBF during carotid endarterectomy alerts the surgeon to the need for a shunt. In the surgery of intracranial aneurysms, it can detect cerebral ischemia secondary to temporary vessel occlusion or determine the optimal anesthetic doses for brain protection.