Moderate hypotensive anaesthesia for reduction of blood loss during total hip replacement.

Thirty-two consecutive patients scheduled for total hip replacement were randomly allocated to receive either neurolept anaesthesia or halothane anaesthesia. In the halothane group, systolic blood pressure was reduced to 10.69-13.33 kPa in normotensive patients, and to 13.33-16.0 kPa in hypertensive patients by adjusting the inspired halothane concentration and using supplementary fentanyl when necessary. In the neurolept group, no attempt was made to reduce blood pressure below the level achieved with adequate anaesthetic doses of fentanyl and droperidol. The average peroperative blood loss in the halothane group was 809 ml (range 250-1700 ml); this was significantly lower than in the neurolept anaesthesia group in which an average blood loss of 1909 ml (range 600-4900 ml) occurred. Moderate hypotensive halothane anaesthesia is recommended as an anaesthetic technique for total hip replacement.