The effect of furosemide on renal blood flow and renal tissue oxygen tension in dogs.

The effect of furosemide (2 mg/kg i.v.) on blood flowin the renal artery and the tissue oxygen tension of the renal cortex and medulla was investigated in six dogs. The flow was measured with an electromagnetic flowmeter and the tissue oxygen tension with IBC tissue oxygen electrodes. The flow in the renal artery increased significantly (p less than 0.05) 5-15 minutes after furosemide administration. 40 minutes after the injection the flow had returned to its initial level. The tissue oxygen tension of both the cortex and the medulla showed significant elevation following furosemide administration. The maximum increase of tissue oxygen tension was recorded 10-20 minutes after the injection. The oxygen tension values exceeded the initial level by 22% in the cortex and by 48% (p less than 0.001) in the medulla. Simultaneously, with the changes in oxygen tension, urine output increase considerably and urine osmolality declined. Application of these renal effects of furosemide in clinical work, particularly in cardiopulmonary bypass surgery, is discussed.