A Comparative Evaluation of Intravenous Dexmedetomidine and Clonidine as Premedic Ation for Prolongation of Bupiva Caine Subarachnoid Block for Lower Limb Orthopaedic Surgery

Abstract

BACKGROUND: Addition of α2 adrenergic agonists with local anaesthetics in bupivacaine spinal anaesthesia prolongs the duration of sensory and motor blockade and postoperative analgesia with minimal haemodynamic alterations. AIM AND OBJECTIVES: To compare and evaluate the efficacy of intravenous dexmedetomidine and clonidine as premedication on subarachnoid blockade duration, postoperative analgesia, and sedation score in patients undergoing lower limb orthopaedic surgeries in bupivacaine (0.5%) heavy intrathecal block. MATERIALS AND METHODS:We carried out a prospective, randomized, double blind study in which 60 patients of ASA status I or II, scheduled for orthopaedic lower limb surgery under spinal anaesthesia, were randomly allocated into two groups of 30 each group A and group B. Group A received dexmedetomidine 0.5µg/kg IV and group B received clonidine 1µg/kg in 10 ml of normal saline intravenously as premedication over 10 min., before subarachnoid blockade with 3.0 ml. of 0.5% hyperbaric bupivacaine. Onset time and regression times of both sensory and motor blockade, haemodynamic parameters were recorded. Duration of postoperative analgesia and sedation score with adverse effects were also recorded. RESULTS: The sensory block level was higher (T5-T7) and earlier in onset (1.81±1.75min.) in dexmedetomidine group than clonidine with level (T6-T8) and onset (2.56±1.62min.). Dexmedetomidine also increased the onset (3.54±3.07min.) and duration (265.45±41.50min.) of motor block achieved as compared to clonidine. The Ramsay sedation score was also greater in dexmedetomidine group than clonidine group (P<0.0001).CONCLUSION: Single dose of premedication with intravenous dexmedetomidine is better than intravenous clonidine during bupivacaine spinal anaesthesia in orthopaedic lower limb surgeries for prolongation of sensory and motor blockade.

A comparative study of intravenous dexmedetomidine and clonidine as pre-emptive analgesia to intrathecal bupivacaine in subarachnoid block - A randomized double blind study

“…Hemodynamic parameters were found to be stable in both groups. In a study conducted by Chavi Sethi et al, 7 authors stated similar results when dexmedetomidine was given intravenously at 0.5mcg/kg before subarachnoid block with hyperbaric bupivacaine.…”