Renal Response to Nonshocking Hemorrhage: the Role of Intrarenal Shunts

¹ From the Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut

In anesthetized dogs, bleeding (1.5–3% of the body weight) was allowed while renal arterial pressure was maintained at constant levels by graded changes of mechanical aortic obstruction. The renal hematocrit decreased, (as measured with I¹³¹ albumin and acid hematin, and as compared to the blood hematocrit), primarily as a result of an increased renal plasma volume. These changes are correlated with previously identified alterations of sodium excretion, all independent of renal innervation or arterial blood pressure. It is proposed that hemorrhage may involve an intrarenal redistribution of blood flow favoring diversion of plasma to cell-poor capillaries or to lymphatic spaces.