Protection of the spinal cord with pentobarbital and hypothermia. 
Ischemic spinal cord damage during thoracic aortic operations has not been eliminated despite application of various adjuncts.  We experimentally investigated the protective effects of pentobarbital and hypothermia on the spinal cord subjected to ischemia.  Among nine groups of 6 rabbits each, groups AI to AIII underwent 20-minute infrarenal aortic occlusion, and groups BI to BVI underwent 40-minute occlusion.  Five milligrams per kilogram of pentobarbital was administered to groups AII and BII; 10 mg/kg in groups AIII, BIII, and BVI; 20 mg/kg in group BIV; and none in groups AI, BI, and BV.  In groups BV and BVI, hypothermia was induced.  Forty-eight hours postoperatively, the motor function of the lower limbs was evaluated.  Statistically significant recovery of motor function was observed in animals in groups AII, AIII, BIII, BIV, BV, and BVI.  Pentobarbital showed dose-dependent protective effects of the spinal cord.  Moderate hypothermia alone also showed protective effects.  Combined use of pentobarbital and hypothermia resulted in highly significant recovery of spinal cord function.