Tramèr Martin R, Glynn Chris J
Division of Anaesthesiology, Geneva University Hospitals, CH-1211 Geneva 14, Switzerland.
Pain. 2002 Sep;99(1-2):235-41. doi: 10.1016/s0304-3959(02)00105-7.
Magnesium is a physiological antagonist of both calcium and the NMDA receptor. Patients with chronic pain of a limb (>1 month's duration) were treated with two Bier's blocks (250 mmHg, 10 m) in a randomised, double-blind, cross-over design. They received once 20% magnesium sulphate (500 mg) + lignocaine 1% (75 mg), and once physiological saline + lignocaine 1% (75 mg). The volume of both treatments was 10 ml. Efficacy data from 49 treatments (25 magnesium, 24 placebo) could be analysed. With magnesium-lignocaine, the duration of pain relief as reported by the patients was on average 23 days (95% CI 8-38) compared with 6 days (95% CI 2-10) with lignocaine alone (P = 0.043). With magnesium-lignocaine, 54.2% of patients had more than 50% pain relief compared with 25% with lignocaine alone (number-needed-to-treat 3.5, P = 0.075). With magnesium-lignocaine, 20% of patients had a treatment failure (i.e. pain relief <24 h) compared with 50% with lignocaine alone (number needed-to-treat 3.3, 95% CI 1.8-29, P = 0.038). The magnesium-lignocaine treatment was painful in 52% of patients compared with 8% with lignocaine alone (number-needed-to-harm 2.3, 95% CI 1.5-4.5, P =0.0008). For patients with chronic limb pain, the addition of magnesium to a Bier's block with lignocaine improves and prolongs pain relief and reduces the number of treatment failures. The optimal dose of lignocaine to prevent magnesium-induced aching of the treated limb needs to be established. Bier's block with magnesium-lignocaine may provide a possible treatment alternative in these patients.
镁是钙和N-甲基-D-天冬氨酸（NMDA）受体的生理拮抗剂。采用随机、双盲、交叉设计，对患有肢体慢性疼痛（病程>1个月）的患者进行了两次比尔氏阻滞（250 mmHg，10分钟）治疗。他们分别接受一次20%硫酸镁（500 mg）+1%利多卡因（75 mg），以及一次生理盐水+1%利多卡因（75 mg）。两种治疗的体积均为10 ml。可以分析49次治疗（25次使用镁，24次使用安慰剂）的疗效数据。使用镁-利多卡因时，患者报告的疼痛缓解持续时间平均为23天（95%可信区间8 - 38），而单独使用利多卡因时为6天（95%可信区间2 - 10）（P = 0.043）。使用镁-利多卡因时，54.2%的患者疼痛缓解超过50%，而单独使用利多卡因时为25%（需治疗人数为3.5，P = 0.075）。使用镁-利多卡因时，20%的患者治疗失败（即疼痛缓解<24小时），而单独使用利多卡因时为50%（需治疗人数为3.3，95%可信区间1.8 - 29，P = 0.038）。52%使用镁-利多卡因治疗的患者感到疼痛，而单独使用利多卡因时为8%（伤害需治疗人数为2.3，95%可信区间1.5 - 4.5，P = 0.0008）。对于患有肢体慢性疼痛的患者，在比尔氏阻滞中加入镁与利多卡因可改善并延长疼痛缓解时间，减少治疗失败的次数。需要确定预防镁引起治疗肢体疼痛的利多卡因最佳剂量。镁-利多卡因比尔氏阻滞可能为这些患者提供一种可行的治疗选择。
