Effects of three anaesthesia methods on haemodynamic responses connected with the use of thigh tourniquet in orthopaedic patients.

Haemodynamic changes were studied in 51 patients undergoing orthopaedic surgery of the lower extremity, including exsanguination and thigh tourniquet for longer than 60 min. The patients were randomly divided into three anaesthesia groups: general anaesthesia (including enflurane), epidural anaesthesia (20 ml 0.5% bupivacaine) and spinal anaesthesia (3 ml 0.5% bupivacaine). During the study, five epidural and one spinal patient excluded from haemodynamic comparison required general anaesthesia because of pain from the surgery or ischaemia. In the general anaesthesia group, there was a rise in either systolic or diastolic arterial pressure of over 30% of the control value in 8/15 patients. In the spinal anaesthesia patients, there was a transient rise above 30% in only one patient out of 15 and no rise in the 15 epidural group patients. On the other hand, 11/15 of the epidural patients needed additional analgesics and/or sedation for pain or restlessness. The mean rise in the haemodynamic parameters including CVP was small on inflation of the tourniquet cuff; on deflation there was a mean decrease in CVP of 1-3 cmH2 (0.1-0.3 kPa), the maximum decrease being 8 cmH2O (0.8 kPa). The mean decrease in systolic arterial blood pressure ranged from 2 to 14 mmHg (0.27 to 1.87 kPa) when the cuff was deflated.