Comparison of spinal block after intrathecal clonidine–bupivacaine, buprenorphine–bupivacaine and bupivacaine alone in lower limb surgeries

CONTEXT: Various adjuvants are being used with local anesthetics for prolongation of intraoperative and postoperative analgesia. The α2-adrenergic agonist clonidine and potent opioid buprenorphine have the ability to potentiate the effects of local anesthetics. AIMS: The purpose of this prospective, double-blind study was to compare onset, duration of sensory and motor block, effect on hemodynamics, level of sedation, duration of postoperative analgesia, and any adverse effects of clonidine and buprenorphine. SETTINGS AND DESIGN: Seventy-five American Society of Anesthesiologists Class I and II patients undergoing lower limb surgery under spinal anesthesia were randomly allocated into three Groups A, B, and C. SUBJECTS AND METHODS: Control Group A received injection bupivacaine 0.5% (heavy) 2.5 ml + saline 0.5 ml whereas Group B received injection bupivacaine 0.5% (heavy) 2.5 ml + injection buprenorphine 50 μg and Group C received injection bupivacaine 0.5% (heavy) 2.5 ml + preservative free injection clonidine 50 μg intrathecally. STATISTICAL ANALYSIS USED: Unpaired Student's t-test and Z-test were used for comparing data. RESULTS: Statistically highly significant differences in mean time of sensory regression to L1, mean time to attain the Bromage Score of 1, and mean time of first rescue analgesic request were observed between the three groups. The patients did not suffer any serious side effects. CONCLUSION: Administration of buprenorphine and clonidine intrathecally does potentiate the duration of analgesia, sensory and motor block, with buprenorphine having a long-lasting effect.