[Blockade of renin secretion by epidural anaesthesia (author's transl)].

In order to determine the rule of neurologic stimuli on the renin-angiotensin system, during surgery, plasma renin activity (PRA) was measured in two groups of patients submitted to either general (group I, N = 7) or epidural (group II, N = 5) anaesthesia during total hip replacement. Salt intakes were normal for all patients before the operation and the perfusion rate, of isotonic saline solution was 5 ml/minute during the surgical procedure. A significant rise in PRA was observed after the skin incision in the first group of patients under general anaesthesia. Epidural anaesthesia suppressed the renin response to surgery. The blockade of conduction along nervous pathways afferent from the surgical area and along renal sympathetic pathways explains the effect of epidural anaesthesia. The lack of increase in PRA despite a significant fall in blood pressure after epidural anaesthesia, also suggests an inhibition of the catecholamines secretion.