It is generally recognized that the electroencephalogram is a valuable monitoring device during anesthesia.2-5 Depth of anesthesia may be accurately correlated with various electroencephalographic patterns, and the onset of undesirable cerebral insults, such as hypercapnia, hypoxia, or cerebral ischemica, is rapidly reflected by changes in electrical cortical activity. To study the effect of cardiac bypass and the effectiveness of extracorporeal circulation in respect to cerebral circulation, cortical electrical activity has been monitored continuously during all procedures, employing a cardiopulmonary bypass, at the University of California Medical Center in Los Angeles. The purpose of this paper is to discuss the electroencephalographic records thus obtained from 25 patients during cardiopulmonary-bypass procedures, using the oxygenator. All records were obtained dur-ing the year 1957.
The eight-channel Grass electroencephalograph recording seven bipolar leads with a paper speed