Use of a temporary forearm tourniquet for intravenous regional anaesthesia: a randomised controlled trial

To investigate the effect of a temporary, additional mid-forearm tourniquet on the quality of intravenous regional anaesthesia.

Fifty patients undergoing hand and wrist surgery under intravenous regional anaesthesia (Bier's block) were randomised to receive a temporary mid-forearm tourniquet for 8 min during and after administration of local anaesthetic or to a control group (no tourniquet). The dose of prilocaine was standardised. Onset of block was assessed by response to pinprick in ulnar, radial and median nerve distributions of the hand. Quality of intraoperative anaesthesia was assessed using response to forceps pinch, visual analogue score (VAS) for pain and requirement for supplemental infiltration anaesthesia. Post-operative pain was assessed using VAS.

There was no difference between the groups with respect to intraoperative pain VAS (P = 0.19) or post-operative pain VAS (P = 0.69). More patients in the temporary tourniquet group were numb to pinprick testing in the three nerve distributions of the hand at 4 and 8 min after injection of local anaesthetic (P = 0.038). There was no difference in the requirement for supplemental infiltration of local anaesthetic between the groups.

Our results suggest that a temporary mid-forearm tourniquet might speed the onset of intravenous regional anaesthesia. Although the advantage is lost by the time surgery starts, the technique might permit the use of a smaller dose of local anaesthetic and may have safety advantages by more rapid movement of anaesthetic out of the venous bed. The technique merits further investigation.