The Effects of Dexmedetomidine Added to Spinal bupivacaine for lower limb surgery

Abstract

Background: Intrathecal α2 agonists prolong the duration of action of local anesthetics and reduce the required dose. Dexmedetomidine is a α2 receptor agonist and its α2/α1 selectivity is 8 times higher than that of clonidine. Aims: In this study, we aimed to investigate the effect of adding dexmedetomidine to intrathecal bupivacaine on the onset time and duration of motor and sensory blocks. Methods: Patients were randomly assigned into two groups. Group B(n= 30) patients received 3ml (15mg) of 0.5% bupivacaine +0.5ml normal saline and Group BD (n= 30) patients received 3ml (15 mg) of 0.5% bupivacaine + 0.5ml (5μg) dexmedetomidine. The parameters studied were - onset and total duration of sensory block, onset and total duration of motor block, the most elevated dermatome level, hemodynamic alterations, and any intraoperative and postoperative complications. Results: The two groups were matched for demographic data. Sensory and motor block onset times were similar in both groups. The regression of the sensory block to S1 dermatome and regression of complete motor block were longer in Group BD than Group B (p<0.001). No significant difference were seen between the groups relative to the maximum level of sensory block (p=0.340). Statistically there were no significant differences in hemodynamic alterations and other adverse effects between the groups. Conclusion: We conclude that intrathecal dexmedetomidine addition to bupivacaine for spinal anaesthesia prolongs sensory and motor block durations without any significant adverse effects.