Role of sympathetic nervous system in surviving acute hemorrhage

Abstract

Twenty unanesthetized, chronically sympathectomized-splenectomized dogs were subjected to rapid hemorrhages varying from 29 to 49% of the control blood volume (determined with Cr⁵¹ and T-1824). One to two hours after hemorrhage, the blood volume was again determined and an average fluid replacement of 6.3% of control blood volume was found. The blood volume remaining after hemorrhage was correlated with the fate of the dog. The 50% mortality (or 50% survival) point corresponds to a residual blood volume of 70.5% of control blood volume or 57.5 ml/kg. These values are higher than those previously reported on splenectomized dogs with sympathetics intact, which had 50% mortality with a residual blood volume of 61.0% or 49.5 ml/kg.