Sudden asystole during craniotomy: unrecognized phenytoin toxicity

The authors report a case of intraoperative sinus arrest in an otherwise healthy patient undergoing craniotomy for aneurysm clipping after mild subarachnoid hemorrhage. The sinus arrest was precipitated by a rapid infusion of 1500 mg phenytoin and was successfully treated with standard resuscitative measures. The differential diagnosis of intra-operative cardiac arrest and the mechanisms of action of phenytoin are discussed. The authors emphasize the role of phenytoin in cerebral protection.