Redistribution of Residual Blood Volume in Hemorrhagic Shock; Relation to Lethal Bleeding Volume.

Abstract

Control dogs anesthetized with morphine and barbital were bled to death at the rate of 2 ml./kg./min. Other dogs similarly anesthetized were subjected to a standard hemorrhagic shock procedure and were then bled to death at the same rate 60 min. after reinfusion of the blood previously withdrawn. Residual blood vol. was detd. by a modified Welcker method and partitioned into fractions obtained from the superior cava azygos, inferior cava, and the cardiopulmonary systems. Bleeding vol. was significantly greater in control animals and the corresponding total residual vol. was greater in the shock animal. Partition of blood showed a marked increase in residual blood retained in the inferior vena cava territory and less in the superior cava azygos system. The conclusion is reached that the reduced lethal bleeding vol. of dogs in hemorrhagic shock following reinfusion is not due to reduction in total blood vol. but to pooling of blood in splanchnic vessels.