Blood flow in rats during hemorrhagic shock: differences between surviving and dying animals.

Cardiac output distribution was measured during hemorrhage and hemorrhagic shock in unanaesthetized rats. In comparison to control animals, a varying degree of decreased blood flow was found in the skin, kidneys, splanchnic bed, and carcass. Bronchial and hepatic arterial blood flows were within normal limits for the entire experiment. Whereas the coronary blood flow fluctuated between values higher and lower than normal, the cerebral blood flow values were normal or decreased. When survivors were compared to dying rats, differences were foun in the early and late stages of shock. Initially, the carcass flow in survivors was higher, while the splanchnic flow was lower, than in dying rats. This redistribution of cardiac output may be responsible for an increased venous return and improved chances for survival. At the late stages of shock, survivors had significantly higher bronchial and hepatic arterial blood flow.