Abstract
Adenosine analogues have been used by subarachnoid injection for the treatment of inflammatory and neuropathic pain. There are no data on the use of adenosine in peripheral nerve blocks. The aim of the present study was to determine the analgesic efficacy of adenosine in combination with a local anaesthetic solution for brachial plexus (BP) block.
With local ethics committee approval, 50 consenting adult patients undergoing upper limb surgery were enrolled in this double-blind, prospective, randomized study. Patients with a history of bronchospastic disease were excluded. Patients were instructed not to take theophylline-containing drugs and beverages for at least one day before surgery or on the first postoperative day. A supraclavicular BP block was performed by injecting a mixture totalling 35 ml made up of prilocaine 1% 10 ml and lignocaine 2% 20 ml with adrenaline 1:200 000, and adenosine 10 mg in 5 ml saline (Group 1) or 5 ml saline (Group 2) as a placebo control group. Postoperative analgesia was assessed by time to first rescue analgesia, analgesic consumption in the first 24 hours, and VAS at rest at 4, 8, 12, 16, 20 and 24 hours. Side-effects were also noted.
Vital signs were stable in both groups throughout the operation. There were no significant differences between the groups in onset of motor and sensory block. Time to first pain sensation from block was not significantly longer in the adenosine group (379±336 min) compared with controls (304±249 min, mean±SD, P=0.14). Time to first analgesic requirements and analgesic consumption in the first 24 hours were also similar in both study groups.
In the present study, the addition of adenosine to local anaesthetic in brachial plexus block did not significantly extend the duration of analgesia.