EFFECT OF ACUTE HEMORRHAGE ON ARTERIAL AND VENOUS RESISTANCE.
OKLAHOMA UNIV MEDICAL CENTER OKLAHOMA CITY
Pagination or Media Count:
Early hemodynamic responses to rapid hemorrhage were studied in anesthetized open chest dogs to test whether Leo Sapirsteins hypothesis is correct that an increase in venous resistance leads to shock after hemorrhage instead of an increase in arterial resistance. Electromagnetic blood flow transducers were used to measure cardiac output in the ascending aorta and venous return in the superior and inferior venae cavae. Systemic arterial, peripheral and central venous pressures were measured with strain gauges, and venous pressures were also measured with water manometers. Rapid removal of 30 of the blood volume caused significant p .05 decreases in all measurements. Conclusions about initial hemodynamic responses to massive hemorrhage are 1 total peripheral resistance decreased, 2 large vein resistance to flow, venous return, increased, and 3 the increase in venous resistance was not affected by alpha-adrenergic blockade. The increase in large vein resistance with hemorrhage suggests that the combination of the vis a fronte force attracting blood into the heart and a decreasing vis a tergo force driving blood from arterial system into the veins may bring about a partial collapse of the large veins. Author
- Anatomy and Physiology
- Medicine and Medical Research