Regional anaesthetic technique and the incidence of tourniquet pain

Abstract

The influence of regional anaesthetic technique on the incidence of lower extremity tourniquet pain was evaluated. We studied 60 patients undergoing orthopaedic procedures of the lower extremity with the use of a pneumatic tourniquet and anticipated inflation of 60 min or longer. Three different anaesthetic techniques were selected by random and draw; spinal anaesthesia (SAB) with plain 0.5% bupivacaine (15 mg) and 0.2 mg epinephrine added, lumbar epidural anaesthesia (EA) with 2% mepivacaine and 1:200,000 epinephrine added, and epidural anaesthesia (AEA) with the same solution alkalinized with bicarbonate. Onset and level of sensory blockade were determined by loss of painful sensation to pinprick. The incidence of tourniquet pain was determined at 15-min intervals or by patient complaint, by an observer unaware of group. Time to onset of pain, amount of treatment (i.v. fentanyl), and sensory level at the time of pain were determined. The SAB was compared with EA and AEA, and EA was compared with AEA. The SAB group was older. The sensory level achieved and duration of tourniquet inflation did not differ among groups. The incidence of tourniquet pain was lower with SAB than with EA and lower with AEA than with EA. There was no difference between SAB and AEA. This study demonstrated a lower incidence of tourniquet pain with spinal anaesthesia than with epidural anaesthesia to the same sensory level. However, this advantage is eliminated if the epidural anaesthetic was performed with an alkalinized local anaesthetic.