Preferential Cerebral Hypothermia

Abstract

Brain cooling by carotid perfusion of OC tromethamine buffered Ringer's solution, with or without 2.5% dextran 40, provided tolerance to total body ischemia of 90 minutes' duration without evidence of neurologic damage. This was observed in baboons precooled to 29 to 30 C (84.2 to 86 F) and perfused for six minutes after circulatory arrest. Ischemic periods of up to 120 minutes were associated with 100% survival without evidence of brain damage but resulted in some degree of spinal cord damage. There was no evidence that the addition of dextran 40 (2.5%) contributed any benefit beyond that provided by the buffering and hemodilution of the tromethamine-Ringer's alone. These findings of extended tolerance to circulatory arrest resulted from a procedure that does not involve cardiopulmonary bypass or extracorporeal circulation.