Anesthetic techniques and surgical blood loss in total hip arthroplasty.

Blood loss during total hip arthroplasty and the relation of different anesthetic techniques to surgical bleeding was explored in a consecutive, prospective study involving 157 patients with no previous history of hip surgery. Intraoperative blood loss was significantly reduced in patients operated under sodium nitroprusside induced hypotensive anesthesia as compared to halothane, NLA or epidural block. It might be suspected that postoperative blood loss is increased when the lowered blood pressure is raised towards normotension, but this was not the case. However, regression analysis between mean arterial pressure and intraoperative blood loss in patients anesthetized with hypotensive as well as "normotensive" techniques showed a poor correlation. Blood loss was greater with NLA and halothane anesthesia than with epidural block. The authors consider controlled hypotension a useful adjuvant in anesthesia for total hip arthroplasty in selected patients. Epidural block, on the other hand, is a suitable anesthetic technique for most patients and has the additional advantage of reduced surgical bleeding as compared to general anesthesia.