Influence of hemorrhagic shock on renal hemodynamics and osmolar clearance in the dog.

Abstract

Renal hemodynamic alterations and accompanying changes in osmolar and free water clearance were examined during hemorrhagic shock in the dog. Deductions based upon application of p-aminohippurate and creatinine extractions to directly measured renal plasma flow indicated that hemodynamic alterations resulting from hemorrhage favored washout of kidney osmolar constituents; namely, some persistence of medullary blood flow was accompanied by severely curtailed glomerular filtration. Evidence for washout included the finding of concentrations of osmolality and sodium higher in the renal venous blood than arterial inflow. Turnover rates were calculated from the arteriovenous differences and plasma flow. The washout of osmolality and sodium coincided with the loss of concentrating power of the kidney, as manifested by such indications as shift in CHH2O from negative to positive values, and decrease in U/P of osmolality to ratios approximating 1.0 in the posttransfusion phase.