Clinical Comparison of Adding Sulfate Magnesium and Dexmedetomidine in Axillary Plexus Block for Prolonging the Duration of Sensory and Motor Block: Study Protocol for a Double-blind Randomized Clinical Trial.

Background: The purpose of this study was to compare the effect of magnesium sulfate adjunct to dexmedetomidine on increasing the duration of sensory and motor block in axillary block.

Materials And Methods: This study is a double-blind clinical trial. Ninety-nine patients were included in the study. They were undergoing forearm and hand surgery and were referred to Vali-e-Asr Hospital in Arak. The patients were divided into three groups. The first group received lidocaine (1.5%) and dexmedetomidine (0.5 μg/kg). The second group patients were given lidocaine (1.5%) plus magnesium. In the control group, lidocaine (1.5%) was adjusted to 35 cc with normal saline. The final volume was 35 cc in the three groups. Sensory and motor block and pain were measured and data were analyzed using SPSS v. 20. The final volume was 35 cc in the three groups.

Results: The sensory and motor block onset time and the stabilization time of the sensory and motor block in the magnesium sulfate group were lower (p<0/001). Pain in recovery, 2, 4, 6, 12, and 24 hours after surgery was lower in the magnesium sulfate group when compared with the dexmedetomidine group (p<0.001). The lowest dose of opioid was used in the dexmedetomidine group 24 hours after surgery (p<0.001).

Conclusion: The results showed that dexmedetomidine decreases pain. Magnesium sulfate increased the sensory and motor block onset time, and the sensory and motor block stabilization time, but dexmedetomidine increases the motor block duration.