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.
Bacalzo LV, Wolfson SK. Preferential Cerebral HypothermiaTromethamine and Dextran 40 and Tolerance to Circulatory Arrest of 90 to 120 Minutes. Arch Surg. 1971;103(3):393-397. doi:10.1001/archsurg.1971.01350090075016