Efficacy of Clonidine versus Dexmedetomidine as Adjuvants to 0.5% Ropivacaine in Nerve Stimulator Guided Supraclavicular Brachial Plexus Block- A Randomised Clinical Study

Abstract

Introduction: Supraclavicular brachial plexus block is used for providing pain relief in upper limb surgeries and has many advantages over general anaesthesia. Alpha-2-adrenergic agonists are chosen with local anaesthetics for their sedative, analgesic and antihypertensive properties. Aim: To compare the efficacy of clonidine and dexmedetomidine when added to 0.5% ropivacaine in nerve stimulator guided supraclavicular block when performed for upper limb surgeries. Materials and Methods: This randomised clinical study was conducted in the Department of Anaesthesia Mata Chanan Devi Hospital, New Delhi, India (tertiary care center), from September 2015 to September 2016. Total 90 patients were randomly allocated into three groups. Group A {Inj. ropivacaine 0.5% (29 mL)+ normal saline 1 mL to make 30 mL}, group B {Inj. ropivacaine 0.5% (29 mL)+ clonidine 1 μg kg-1 to make 30 mL) and group C {Inj. ropivacaine 0.5% (29 mL)+ dexmedetomidine 1 μg kg-1 to make 30 mL}. Parameters observed included onset of sensory and motor block, total motor duration, postoperative analgesia as primary outcome; and intraoperative haemodynamic parameters and side effects as secondary outcome. Results: All the three groups were found to be similar with demographic profile. Patients in dexmedetomidine group showed faster onset and longer duration of sensory and motor blocks (p-value<0.01). The mean onset of sensory block in minutes was 12.03±2.20, 8.20±1.40, 6.80±1.35 in groups A, B and C, respectively (p-value<0.001). The mean onset of motor block in minutes was 18.47±2.78, 13.37±2.86 and 11.30±2.04 in group A, group B and C, respectively (p-value<0.001). The mean duration of analgesia in group A, B and C was 555.17±65.36, 710.00±73.58 and 902.67±116.65 minutes, respectively (p-value<0.001). The mean duration of motor block in group A, group B and group C were 330.00±51.78, 418.17±38.29 and 516.83±50.33 minutes, respectively (p<0.0001). The duration of postoperative analgesia and total motor duration were significantly prolonged in dexmedetomidine group than group A and B. Conclusion: It can be concluded that both clonidine and dexmedetomidine increases the total motor duration and postoperative analgesia when added to ropivacaine, but dexmedetomidine is a better choice when used in supraclavicular block, without any significant side-effects.