The effect of adrenergic blockade and norepinephrine on renal and cardiovascular hemodynamics following hemorrhage.

VASOPRESSOR. agents produce renal vasoconstrie.tion when administered to normotensive animals and man." Because of this vasoconstrictor activity, the question has been raised whether these agents might not actually be harmful' G to the kidney when used to elevate blood pressure for the treatment of shock. Observations made recently' s indicate that when renal and cerebral blood flow are markedly depressed due to hypotension resulting from ganglionic blocking agents, administering a vasopressor agent will actually increase blood flow to these vascular beds. Although the circumstances are not analogous to shock, these results do suggest a paradox since, when vasopressor agents are administered to normotensive subjects, and the blood pressure is raised to hypertensive levels, cerebral and renal blood flow are depressed. The current observations were made on dogs in order to determine whether the administration of vasopressor agents would increase renal blood flow in the presence of hypotension due to hemorrhage. Concurrent observations were made on cardiac output. Since adrenergic blockade has been reported