From the Departments of Anesthesiology (J.P.M., W.D.W., M.V.P., M.B., M.S.-S., M.F.N.), Neurology (D.T.L.), Psychiatry (J.A.B.), and Surgery (C.A.M.), Duke University Medical Center, Durham, NC; and Department of Anesthesiology, Sentara Cardiovascular Research Institute, Norfolk, VA (D.B.S.).
Stroke. 2013 Dec;44(12):3407-13. doi: 10.1161/STROKEAHA.113.002703. Epub 2013 Oct 8.
Neurocognitive decline occurs frequently after cardiac surgery and persists in a significant number of patients. Magnesium is thought to provide neuroprotection by preservation of cellular energy metabolism, blockade of the N-methyl-D-aspartate receptor, diminution of the inflammatory response, and inhibition of platelet activation. We therefore hypothesized that intraoperative magnesium administration would decrease postoperative cognitive impairment.
After approval by the Duke University Health System Institutional Review Board, 389 patients undergoing cardiac surgery were enrolled in this prospective, randomized, double-blind, placebo-controlled clinical trial. Subjects were randomized to receive magnesium as a 50 mg/kg bolus followed by another 50 mg/kg infusion for 3 hours or placebo bolus and infusion. Cognitive function was assessed preoperatively and again at 6 weeks postoperatively using a standardized test battery. Mean CD11b fluorescence and percentage of platelets expressing CD62P, which are markers of leukocyte and platelet activation, respectively, were assessed by flow cytometry as a secondary outcome. The effect of magnesium on postoperative cognition was tested using multivariable regression modeling, adjusting for age, years of education, baseline cognition, sex, race, and weight.
Among the 389 allocated subjects (magnesium: n=198; placebo: n=191), the incidence of cognitive deficit in the magnesium group was 44.4% compared with 44.9% in the placebo group (P=0.93). The cognitive change score and platelet and leukocyte activation were also not different between the groups. Multivariable analysis revealed a marginal interaction between treatment group and weight such that heavier subjects receiving magnesium were less likely to have cognitive deficit (P=0.06).
Magnesium administered intravenously during cardiac surgery does not reduce postoperative cognitive dysfunction.
http://www.clinicaltrials.gov. Unique identifier: NCT00041392.
心脏手术后常发生神经认知功能减退，且相当一部分患者持续存在。镁被认为可通过维持细胞能量代谢、阻断 N-甲基-D-天冬氨酸受体、减少炎症反应和抑制血小板激活来提供神经保护。因此，我们假设术中给予镁可减少术后认知障碍。
在获得杜克大学健康系统机构审查委员会批准后，对 389 例行心脏手术的患者进行了这项前瞻性、随机、双盲、安慰剂对照的临床试验。患者被随机分配接受镁，方法为 50mg/kg 推注，然后再用 50mg/kg 输注 3 小时，或接受安慰剂推注和输注。采用标准化测试组合在术前和术后 6 周评估认知功能。采用流式细胞术评估白细胞和血小板活化的标志物 CD11b 荧光强度和血小板表达 CD62P 的百分比，作为次要终点。使用多变量回归模型，根据年龄、受教育年限、基线认知、性别、种族和体重，调整术后认知的镁作用。
在 389 名分配的受试者中（镁组：n=198；安慰剂组：n=191），镁组的认知缺陷发生率为 44.4%，安慰剂组为 44.9%（P=0.93）。镁组和安慰剂组的认知变化评分以及血小板和白细胞活化也无差异。多变量分析显示，治疗组和体重之间存在边缘交互作用，即接受镁的较重患者发生认知缺陷的可能性较小（P=0.06）。
心脏手术期间静脉内给予镁不能减少术后认知功能障碍。
