RENAL HEMODYNAMICS AND OXYGEN CONSUMPTION IN EXPERIMENTAL CHRONIC HYPOXIA

Chronic hypoxia and polycythemia were produced in dogs by anastomosing the inferior vena cava end-to-end to the right inferior pulmonary vein, diverting all inferior caval blood flow into the left atrium. The resultant arterial desaturation ranged from 67%, 2 to 7 days after shunting, to 80% 8 months later. A progressive increase in hematocrit and left heart output after the right-to-left shunt was noted, resulting in increased oxygen transport with the passage of time. An experimental technique was developed for monitoring renal hemodynamics which was relatively atraumatic, not requiring a laparotomy or other major surgery. Utilizing this technique, it was found that chronic hypoxia increased renal blood flow and decreased renal vascular resistance. The data thus imply renal vasodilatation or opening of arteriovenous shunts when the kidney is chronically exposed to a low arterial pO2 (33-54 mm. Hg). In this range of arterial oxygen tension, renal O2 consumption did not differ significantly from normal, and there was no evidence of conversion from aerobic to anaerobic renal metabolism. Although production of chronic hypoxemia resulted in significant erythropoiesis (hematocrit 55% 8 months after operation), no enlargement of the kidneys by weight was noted at the completion of the study. © 1969.