We performed a double-blind, randomised controlled trial to assess the effectiveness of a continuous-infusion
brachial plexus block with
levobupivacaine compared with that of a standard single injection for the management of
post-operative pain after surgery on the shoulder. Eight patients were randomised to receive a pre-operative
brachial plexus block using 30 ml of
levobupivacaine 0.5% with
adrenaline 1:200 000 followed by insertion of a 20-gauge
polyamide catheter. This was connected to a disposable elastometric pump, set immediately after surgery to administer a continuous flow of
levobupivacaine 0.25% at a rate of 5 ml per hour. The other eight patients were randomised to receive only the initial injection of 30 ml. The study was double-blinded with the aid of
sham catheters and clamped pumps. All patients were given regular
paracetamol and were prescribed
morphine through a
patient-controlled analgesia pump. Motor and sensory block assessments, visual analogue scale
pain scores and consumption of
morphine were recorded after the operation and then at 6, 12 and 24 hours after administration of the block. Satisfactory motor and sensory block was achieved in all patients. The mean visual analogue scale
pain score at 12 hours and consumption of
morphine at 24 hours after injection were significantly lower (p < 0.05) in the continuous-infusion group. This group also took longer to request their first additional
analgesia and reported a significantly higher overall level of satisfaction. Our study has shown that continuous interscalene infusion of
levobupivacaine is an effective method of post-operative
analgesia after major surgery of the shoulder.