Abstract: The present invention is concerned with improved aqueous asanguineous perfusates, blood substitutes for profound hypothermia, and method of using the same. The perfusates comprise:______________________________________ Component Molar Conc., mM Grams/liter ______________________________________ Hydroxyethyl starch, 40 to 60 gms MW = 500,000 Glucose 5-15 0.9-2.7 Sodium bicarbonate 5-20 0.42-1.68 Potassium chloride 15-40 1.15-3.33 Calcium chloride 0.5-2.04 0.074-0.294 Magnesium chloride 0.25-2.5 0.051-0.510 HEPES or THAM 7.2-15 1.72-3.90 Sodium phosphate, 7.2-15 monobasic, MW = 120.0 Mannitol or sucrose 0-170 0-30.97.