The intent of the technique to be studied is to induce a state of hypothermic preservation in trauma victims who have exsanguinated to the point of cardiac arrest. In appropriately selected subjects, after an initial emergency attempt at resuscitation with standard techniques, an arterial catheter will be inserted into the descending thoracic aorta. Using appropriate tubing, pump, and heat exchanger,a large quantity of ice-cold saline (0.9% Sodium Chloride for Injection USP) will be pumped as rapidly as possible into the aorta with the goal of cooling the brain (tympanic membrane temperature, Tty) to <10 C. If possible, a large venous catheter will be placed and recirculation of fluid established.