Predicting ischemic brain injury after intraoperative cardiac arrest during cardiac surgery using the BIS monitor

Two patients in whom the bispectral index (BIS) decreased to zero following cardiac arrest during cardiothoracic surgery are described. The BIS value decreased to zero after cardiac arrest, and the value remained low for the remainder of the anesthetic despite successful cardiopulmonary resuscitation. Both patients were found to have severe brain injuries in the postoperative period.