[Acute and massive hemorrhage: mechanisms of compensation and damage]

To evaluate the body's compensatory reserves, experiments were made on anesthetized (with heparine) mongrel dogs of both sexes weighing 8-25 kg. The experiments have indicated that early monitoring of physiological parameters (external respiration, cardiovascular performance, hemostasis, red blood cell morphometry) in the first 5-10 minutes of acute massive hemorrhage is of high informative value. The generalization of vasoconstriction resulting in higher overall blood volume, the maintenance of venous return, tachypnea, active spontaneous hemodilution, and increased heart rate are the leading mechanisms of perfusion pressure maintenance in early acute hemorrhage. The severity of acute damage to the membranes of red blood cells and endotheliocytes and hence changes occurring in the suspension structure of blood, which drastically impairs its rheological parameters and fluidity, can play the key role in the pathogenesis of decompensatory cardiovascular and visceral functions in prolonged arterial hypotension. The findings open up new possibilities for early evaluation and prediction of the ensurina course of delayed massive hemorrhage.