Deep hypothermic circulatory arrest: II. Changes in electroencephalogram and evoked potentials during rewarming.

Publication/Presentation Date

1-1-2001

Abstract

BACKGROUND: Electrophysiologic studies during rewarming after deep hypothermic circulatory arrest probe the state of the brain during this critical period and may provide insight into the neurological effects of circulatory arrest and the neurologic outcome.

METHODS: Electroencephalogram (EEG) and evoked potentials were monitored during rewarming in 109 patients undergoing aortic surgery with hypothermic circulatory arrest.

RESULTS: The sequence of neurophysiologic events during rewarming did not mirror the events during cooling. The evoked potentials recovered first followed by EEG burst-suppression and then continuous EEG. The time to recovery of the evoked potentials N20-P22 complex was significantly correlated with the time of circulatory arrest even in patients without postoperative neurologic deficits (r = 0.37, (p = 0.002). The nasopharyngeal temperatures at which continuous EEG activity and the N20-P22 complex returned were strongly correlated (r = 0.44, p = 0.0002; r = 0.41, p = 0.00003) with postoperative neurologic impairment. Specifically, the relative risk for postoperative neurologic impairment increased by a factor of 1.56 (95% CI 1.1 to 2.2) for every degree increase in temperature at which the EEG first became continuous.

CONCLUSIONS: No trend toward shortened recovery times or improved neurologic outcome was noted with lower temperatures at circulatory arrest, indicating that the process of cooling to electrocerebral silence produced a relatively uniform degree of cerebral protection, independent of the actual nasopharyngeal temperature.

Volume

71

Issue

1

First Page

22

Last Page

28

ISSN

0003-4975

Disciplines

Medicine and Health Sciences

PubMedID

11216751

Department(s)

Department of Surgery

Document Type

Article

Link to Full Text

Share

COinS