Shah Prerana N, Dhengle Yamini
Department of Anaesthesiology, Seth GSMC & KEM Hospital, Maharashtra, India.
Acta Anaesthesiol Taiwan. 2016 Jun;54(2):62-4. doi: 10.1016/j.aat.2016.06.003. Epub 2016 Jul 16.
Magnesium has been proven to have antinociceptive effects in animal and human models of pain. Its effect is primarily based on the regulation of calcium influx into the cell, which is natural physiological calcium antagonism and N-methyl-d-aspartate (NMDA) receptor antagonism.
One hundred and eight patients undergoing surgery with spinal anesthesia received either 250 mg of intravenous magnesium sulfate followed by an infusion of 500 mg magnesium sulfate (25 mg/mL) at the rate of 20 mL/hour; or the same volume of normal saline (control group) as bolus and infusion. The primary end-points in the study were to evaluate the analgesic effect and duration of sensory and motor blockade. The secondary end-points included assessment of hemodynamic effects of intravenous magnesium sulfate and rescue analgesia requirement.
Sensory and motor blockade, respectively, were 25 minutes and 34 minutes shorter in the control group. Less patients in the magnesium group (33% vs. 53.7%) than in control group required rescue analgesia in the postoperative period. The control group required rescue analgesia nearly 3 hours earlier than the magnesium group. Only one patient in the control group experienced bradycardia. There was no event of intraoperative hypotension in either of the groups.
Intravenous magnesium sulfate when given as a bolus, followed by an infusion, delayed and decreased the need of rescue analgesics after spinal anesthesia.
镁已被证实在动物和人类疼痛模型中具有抗伤害感受作用。其作用主要基于对钙离子流入细胞的调节，这是一种天然的生理钙拮抗作用和N-甲基-D-天冬氨酸（NMDA）受体拮抗作用。
108例接受脊髓麻醉手术的患者，一组静脉注射250mg硫酸镁，随后以20mL/小时的速度输注500mg硫酸镁（25mg/mL）；另一组静脉注射和输注相同体积的生理盐水（对照组）。该研究的主要终点是评估镇痛效果以及感觉和运动阻滞的持续时间。次要终点包括评估静脉注射硫酸镁的血流动力学效应和补救性镇痛的需求。
对照组的感觉和运动阻滞时间分别短25分钟和34分钟。镁组术后需要补救性镇痛的患者（33%对53.7%）少于对照组。对照组比镁组早近3小时需要补救性镇痛。对照组仅1例患者出现心动过缓。两组均未发生术中低血压事件。
静脉注射硫酸镁，先推注后输注，可延迟并减少脊髓麻醉后补救性镇痛的需求。
