Intraoperative anoxic spells in patients with tetralogy of Fallot

: We experienced 5 cases of intraoperative anoxic spell in 48 patients with tetralogy of Fallot (TOF). One of 5 cases had tetralogy with pulmonary atresia (Type A), and the others had tetralogy alone (Type D). The patient of type A who had anoxic spells during preoperative period had been on chronic propranolol therapy. However, the patients of type D had no anoxic spells during preoperative period and one in this type had not been on beta-adrenergic blocking drugs preoperatively. One patient was anesthetized with fentanyl-diazepam-O2, and the others were anesthetized with morphine-diazepam-O2. We used mainly alpha-adrenergic drugs and sodium bicarbonate for the therapy of intraoperative anoxic spells. Concerning the intraoperative anoxic spell, we have to be aware in the management of the patients with TOF, whether the patient had anoxic spells during preoperative period or not.