Addition of dexmedetomidine to bupivacaine in the lumbar plexus block potentiates postoperative analgesia among hip arthroplasty patients: a prospective randomized controlled trial

Background Dexmedetomidine is an α2-adrenergic agonist, which prolongs analgesia when administered in neuroaxial and peripheral nerve blocks. The aim of this study was to evaluate the effect of adding dexmedetomidine to bupivacaine in the lumbar plexus block (LPB) as regards analgesic characteristics and opioid consumption. Materials and methods Fifty patients scheduled for total hip arthroplasty were divided into two groups: group B patients (N = 25) received LPB with 30 ml of 0.25% bupivacaine and 2 ml of normal saline, while group BD patients (N = 25) received LPB with 30 ml of 0.25% bupivacaine and dexmedetomidine 1 μg/kg diluted in 2 ml of normal saline. Time for first analgesic administration, totally used doses of morphine, pain scores, hemodynamic data, and side effects were recorded. Results Demographic and operative characteristics were comparable between the two groups. The time for first analgesic request was longer in group BD than group B [502 vs. 243 min (P 0.001) and the total morphine consumption in 24 h was less among group BD patients compared with those in group B (19 vs. 32 mg, P 0.001)]. The visual analogue score was significantly lower in group BD in the first 8 h postoperatively compared with group B (P 0.001). In group BD a lower heart rate was noticed 120 min postinduction that continued for the first 4 h postoperatively (P 0.001). Conclusion The addition of dexmedetomidine to bupivacaine in LPB prolongs the time for first analgesic requirement and reduces the total postoperative opioid consumption without major side effects.