Comparative study between Magnesium and dexmedetomidine as adjuvant to lidocaine for intravenous regional anesthesia

ABSTRACT

We conducted this study to evaluate the effects of magnesium and dexmedetomidine when added to lidocaine for intravenous regional anesthesia [IVRA]. Forty-five patients undergoing elective hand surgery during IVRA were randomly assigned to three groups. IVRA was achieved with 10ml of saline plus 3mg/kg lidocaine 0.5% diluted with saline to a total of 40ml in group L, 10ml of 10% magnesium sulfate plus 3mg/kg lidocaine 0.5% diluted with saline to a total of 40m1 in group M and 0.5micro g/kg dexmedetornidine plus 3mg/kg lidocaine 0.5% diluted with saline to a total close of 40ml in group D. Injection pain, sensory and motor block onset and recovery time, tourniquet pain, and anesthesia quality were noted, Patients were instructed to receive 75mg of IM diclofenac when the visual analog scale [VAS] score was >4, and analgesic requirements were recorded. Sensory and motor block onset times were shorter and recovery times were prolonged in group M and D. VAS scores of tourniquet pain were lower in group M and D at 15, 20, 30, 40 and 50mm [p<0.001]. Anesthesia quality, as determined by the anesthesiologist and surgeon, was better in group M and D [p<0.05]. Time to the first postoperative analgesic request was 95 +/- 29, l55 +/- 38, 170 +/- 20min in groups L, M, D respectively. There was a statistically difference in VAS scores for tourniquet pain at 15. 20, 30, 40 and 50min after tourniquet inflation [p<0.001] VAS scores were lower in group M and D. Postoperative VAS scores were significantly higher for the first postoperative 6 hours in group L compared with group M [p<0.05]. In group D, postoperative VAS scores were significantly lower for the first postoperative 12 hours compared with group M and L. Diclofenac consumption was significantly less in group M [50 +/- 35mg] and group D [40 +/- 10mg] compared with group L [130 +/- 55mg] and in group D compared with group M [p<0.05]. No adverse effects were seen through the 24 hours postoperative period in the three groups. We conclude that magnesium and dexmedetomidine as an adjuncts, to lidocaine improves the quality of anesthesia and analgesia in IVRA, more in dexmedetomidine group