Effect of intraoperative intervention on neurological outcome based on electroencephalographic monitoring during cardiopulmonary bypass.

Neurological complications of cardiopulmonary bypass procedures are well documented. The present two-part study was undertaken to (1) determine if on-line computerized electroencephalographic changes correlated with neurological outcome and (2) compare neurological outcome with that of a second group of patients who received intraoperative interventions based on electroencephalographic data. Part 1 consisted of monitoring 50 patients. A power drop index was developed that correlated with new global neurological deficits. New global deficits occurred in 44% of the patients. In part 2, this information was used to design intervention criteria. Treatment protocols used previously accepted methods of increasing cerebral blood flow, ie, increasing pump flow, raising mean arterial pressure, and increasing CO2 content in the ventilator blend. Global neurological deficits were reduced to 5% in a group of 41 clinically similar patients (p less than 0.001). Cerebral perfusion pressures were similar in both groups. The single correlating factor was the power drop index as identified by computerized EEG. Our conclusion is that simple intervention guided by computerized EEG can reduce global neurological deficits in patients having cardiopulmonary bypass procedures.