Renal blood flow and intrarenal oxygen tension in haemorrhagic hypotension

The changes occurring in renal cortical and medullary tissue oxygen tensions and in renal total blood flow (RBF) were studied during haemorrhagic hypotension in six dogs. The flow was measured with an electromagnetic flowmeter, and tissue oxygen tension with IBC (Ineternational Biophysics Corporation, USA) oxygen electrodes. Haemorrhagic hypotension led to a considerable decrease in cortical tissue oxygen tension. The decrease in the medullary tissue oxygen tension was smaller, while the renal total flow decreased considerably during haemorrhage. The role of perfusion pressure alone in the redistribution of renal blood flow during haemorrhagic hypotension is discussed.