Subarachnoid blockade and total hip replacement. Effect of ephedrine on intraoperative blood loss.

Thirty-eight patients undergoing total hip replacement under subarachnoid blockade were allocated randomly to one of two groups. Following institution of the blockade, patients in group A received ephedrine i.v. to maintain the systolic arterial pressure at, or above 100 mm Hg. Patients in group B were managed in an identical way, but did not receive ephedrine. Significant differences in arterial pressure (P less than 0.001), and heart rate (P less than 0.005), but no significant difference in blood loss was observed in the two groups. This was confirmed by similar blood transfusion requirements and postoperative haemoglobin concentrations. The relevance of the use of pressor agents in spinal anaesthesia is discussed.