A prospective randomised comparative study of verapamil (2.5mg) or dexmedetomidine (0.5μg/kg) as adjuvants to lidocaine in intravenous regional anaesthesia for distal upper limb surgeries

Abstract

Background and Objectives: Intravenous regional anesthesia (IVRA) is one of the simple, cost effective anesthetic technique for the distal upper limb surgeries that provides reliable and rapid analgesia with good muscle relaxation of the extremity distal to the tourniquet. However tourniquet pain, absence of post- operative analgesia and occurrence of local anesthetic systemic toxicity in case of accidental or early tourniquet deflation are the major draw backs. Materials and Methods: In this prospective, randomized, double blinded, comparative study,60 patients aged between 20-60 years with ASA class 1 and 2, posted for distal upper limb surgeries (forearm and hand) were selected for IVRA technique. The study population were assigned in to two groups (n=30) to receive either lidocaine 0.5% 3mg/kg diluted up to 40ml with 2.5mg verapamil ( Group LV) or lidocaine 0.5% 3mg/kg diluted up to 40ml with dexmedetomidine 0.5μg/kg( Group LD). Parameters like sensory and motor block onset times, sensory and motor block recovery times, tourniquet tolerance, sedation, post -operative VAS score, time of rescue analgesia, duration of analgesia were assessed. The data was statistically analysed with appropriate tests. Results: There was no statistically significant difference with respect to onset of sensory block in both the groups (3.38±0.44 in Group LV vs 3.43±0.39 in Group LD). Onset of motor blockade was faster in Group LV (8.77±0.74min) compared to Group LD (9.44±0.77min) (p<0.001). Sensory recovery time was significantly prolonged in Group LV (17.89±1.66min) compared to Group LD (8.76±0.94min) (p<0.001). Onset of second tourniquet pain was significantly prolonged in Group LD (51.60±2.25 min) compared to Group LV 49.27±2.32min) (p<0.001). There was significantly prolonged duration of analgesia in Group LV (253.70±18.29min) when compared to Group LD (181.68±13.74min)(p<0.001). Significantly higher sedation score was noted at 1st and 2hr in Group LD when compared to Group LV (p<0.001). There was no significant differences in VAS score and hemodynamic parameters between both the group. (p>0.005). Conclusion: Verapamil 2.5mg as an adjuvant to lidocaine for IVRA for distal upper limb surgeries significantly facilitates sensory, motor onset and prolongs sensory recovery time with prolonged duration of postoperative analgesia with lesser sedations when compared 0.5μg/kg dexmeditomidine, without any significant changes in hemodynamic parameters or any adverse events.