COMPARATIVE EFFECTS OF INDUCED HYPOTENSION AND NORMOVOLAEMIC HAEMODILUTION ON BLOOD LOSS IN TOTAL HIP ARTHROPLASTY

The effects of deliberate hypotension and normovolaemic haemodilution on operative blood loss were studied in patients undergoing hip arthroplasty. Thirty patients were anaesthetized with halothane-nitrous oxide, and assigned to one of three groups. In group I, mean arterial pressure was decreased to 55 mm Hg by sodium nitroprusside. In group II, 23 ± 2 ml/kg of blood was withdrawn just before the surgical procedure and replaced by twice the volume with 4% albumin and Ringer lactate solution. The shed blood was reinfused at the end of the surgical procedure. In group III, the blood replacement was equal to blood loss and this group served as control. Intraoperative blood losses were 1050± 185 ml and 900±130 ml in the autotransfused and control groups, respectively, and 320±35 ml in the hypotensive group. However, the total red cell loss was significantly less in the hypotensive and autotransfused groups than in the control group. No complications occurred in any of the three groups. Deliberate hypotension was the most effective means of reducing intraoperative bleeding and the time for this procedure was shorter than for normovolaemic haemodilution combined with autotransfusion.