Use of computerized electroencephalographic monitoring during aneurysm surgery

Abstract

The clinical usefulness of intraoperative electroencephalographic (EEG) monitoring of cerebral perfusion during aneurysm surgery has received little attention, primarily due to problems with electrode placement over the operative site, which is the area of maximal risk. In this report, 27 patients undergoing surgery for anterior circulation aneurysms were monitored intraoperatively with a two-channel computerized EEG complex using a bilateral frontal-occipital montage. In 16 patients, a normal EEG pattern was observed throughout surgery; all 16 awoke neurologically intact and their postoperative angiograms did not reveal cerebral vasospasm. In the other 11 patients, one of two patterns of persistent EEG abnormalities was identified. 1) In six of these patients a marked attenuation of EEG activity was observed ipsilaterally which coincided with various intraoperative events including brain retraction, hypotension, and aneurysm dissection/clipping. Five of these six patients awoke with new neurological deficits which persisted beyond 12 hours in two, both of whom had angiographically proven vasospasm 24 hours after surgery. 2) In the remaining five patients, a distinct abnormal EEG pattern consisting of marked hyperactivity in the delta, theta, and alpha frequency ranges was observed ipsilaterally. Four of these five patients had a poor neurological outcome and vasospasm on their angiogram 24 hours after surgery. Thus, EEG monitoring which spans the operative area during aneurysm surgery is practicable and appears to be of value in the detection of compromised cerebral perfusion during aneurysm surgery. The possible significance of the two abnormal EEG patterns identified in this report is discussed.

Effects of use of Thiopental + Mannitol or Etomidate + Mannitol on Cerebral Ischemia During Temporary Occlusion of Middle Cerebral Artery in Intracranial Aneurysm Surgery

“…Meanwhile, cerebral perfusion may be challenged by increased intracranial pressure, systemic hypotension, or temporary clipping. 38,40 Therefore, the cerebral hemodynamic and metabolic balance may be altered during aneurysm surgery. 41 Jugular bulb venous oximetry allows continuous or intermittant estimation of the global balance between cerebral oxygen demand and supply.…”

Monitoring Techniques for Prevention of Procedure-Related Ischemic Damage in Aneurysm Surgery

“…The criteria used for this purpose include the disappearance of alpha and beta frequencies and a predominance of delta frequencies, the attenuation of at least 75% of all the activities (66,130) or an increase of Ͼ 100% of delta activities Ͻ 1 Hz (21). An impairment of autoregulation associated with subarachnoid hemorrhage or related to intraoperative maneuvers such as brain retraction, hypotension, or clipping of the aneurysm represents an abnormal intraoperative finding that can be detected as areas of attenuation and areas of hyperactivity (120).…”