Plasma renin activity, renal artery blood flow and cortical tissue oxygen tensionin haemorrhagic hypotension.

The changes occurring in plasma renin activity (PRA), tissue oxygen tension of the renal cortex and the change in renal total blood flow were studied during haemorrhagic hypotension in six dogs. The flow was measured with an electromagnetic flowmeter, the plasma renin activity was determined by radioimmunoassay and tissue oxygen tension with IBC oxygen electrodes. Haemorrhagic hypotension led to a significan increase in PRA. The fall in renal total blood flow and cortical tissue oxygen tension were significant after all three epizodes of bleeding (each of 10 ml/kg. Metabolic acidosis increased after every bleed. The correlation between PRA, renal blood flow and cortical tissue oxygen tension is evaluated in the discussion.