The Analgesic Effects of Addition of Dexamethasone to Bupivacaine-Based Axillary Brachial Plexus Block for Upper Limb Surgeries - Abstract
Background: Axillary brachial plexus block approach provides surgical anaesthesia for below elbow procedures with the major advantage of simplicity, excellent safety profile and avoidance of the numerous risks of general anaesthesia. The ideal adjuvants and concentration of bupivacaine to prolong the duration of action with good safety profile are yet to be identified. Objective: The aim of this study was to evaluate the analgesic adjuvant effect of dexamethasone when combined with bupivacaine in axillary brachial plexus block. Methodology: Ethical clearance for this study was obtained from Health Research and Ethics Committee of Federal Medical Centre, Owerri, Imo State. A total of 50 consented ASA I and II adults aged between 18 and 60 years, were recruited for this prospective randomized double-blind study to Group BD (n = 25), to receive 2mL (8mg) of dexamethasone added to 40mL of 0.25% bupivacaine or Group BN (n = 25) to receive 2mL of normal saline added to 40mL of 0.25% bupivacaine. Axillary brachial plexus block was done with the aid of a peripheral nerve stimulator and the block onset time, duration of the block, pain scores, postoperative opioid consumption and incidence of side effects were measured and recorded. Data were entered into a data collection form and analyzed with the statistical package for social sciences version 20. A p-value of < 0.05 was considered significant. Result: A total of 50 patients were recruited for this study, however, only 48 participants completed the study. The mean onset time of sensory and motor blocks in Group BD were significantly shorter (9.62±1.14 min and 12.61±0.93 min) than Group BN (10.62±1.57 min and 13.81±1.79 min), p=0.02 and p=0.01 respectively. The mean duration of sensory and motor blocks was significantly prolonged in Group BD (673.08±110.20 min and 390.79±39.92min), compared with Group BN (266.58±66.08 min and 233.00±32.32 min), p<0.01 and p<0.01 respectively. The total analgesic (pethidine) consumption in Group BD was significantly less (189.58±22.45 mg), compared to that in Group BN (245.83±17.53 mg), p<0.01. Conclusion: The addition of dexamethasone to bupivacaine in axillary brachial plexus block produces an early onset of action and significantly prolongs both the sensory and motor block with overall reduction in postoperative opioid consumption, with no side effect.