Effects of intrathecal dexmedetomidine vs intrathecal magnesium sulfate as adjuvants in spinal anesthesia

Abstract

Aim Intrathecal adjuvants are used for prolongation of duration of subarachnoid block and provide adequate analgesia. This study was designed to evaluate the onset, duration, and regression of sensory and motor block of intrathecal dexmedetomidine vs magnesium sulfate as an adjuvant to 0.5% hyperbaric bupivacaine for spinal anesthesia. Materials and methods Sixty patients aged 21–50 years, with American Society of Anesthesiologists status I, II scheduled for elective lower abdominal and lower limb surgeries, were divided into three equal groups in a randomized-controlled manner: the control group (S: n=20) received 15 mg hyperbaric bupivacaine (3 ml) and 1 ml saline, the dexmedetomidine group (DXM: n=20) received15 mg hyperbaric bupivacaine (3 ml) and 10 µg of dexmedetomidine, and the magnesium sulfate group (Mg: n=20) received 15 mg hyperbaric bupivacaine (3 ml) and 50 mg of magnesium sulfate. Hemodynamic variables such as heart rate, systolic and diastolic blood pressure, onset of sensory and motor block, regression time, time to first analgesic request, and adverse effects were recorded for each patient. Results The onset time of sensory and motor block was rapid in the DXM group in comparison with the Mg and control groups. The onset time of sensory and motor blockade were delayed in the Mg group in comparison with the S group. The regression time of sensory and motor blockade was prolonged in the DXM group and in the Mg group compared with the S group. Demand for analgesia was significantly late in the DXM group compared with the Mg and control groups, but early in the control group. Conclusion Dexmedetomidine had faster onset of sensory and motor blocks, and provided prolonged postoperative analgesia compared with the magnesium sulfate and control groups