Comparison of the Efficacy of Oral versus Intravascular Magnesium in the Prevention of Hypomagnesemia and Arrhythmia after CABG

Abstract Objective: Cardiac arrhythmias are a common challenge following open-heart surgeries. Hypomagnesemia is believed to be correlated with this condition. Prophylactic intravenous magnesium supplementation has been practiced for a long time in patients undergoing CABG. This study was designed in an attempt to compare the efficacy of oral versus intravenous routes in the prevention of hypomagnesemia and arrhythmia. Methods: In this interventional clinical study, 82 patients were randomly assigned to 2 groups. All patients were evaluated for baseline serum magnesium level and arrhythmias. One group received 1,600 mg of oral magnesium hydroxide through nasogastric (NG) tube prior to surgery, while the other group received 2 g of magnesium sulfate during the induction of anesthesia. The serum magnesium level was monitored for 48 hours after the operation. The difference in preoperative hypomagnesemia was non-significant (Sig: 0.576). Results: During the operation, the serum magnesium level peaked around 4 mg/dL, and no hypomagnesemia was detected in any patient. Although the curve of oral group declined parallel and below that of intravenous (IV) group, no significant differences were detected during postoperative monitoring. In addition, a prevalence of arrhythmia of 13.9% and 6.5% was noticed in IV and oral groups, respectively (OR: 0.428). Conclusion: Providing 1,600 mg of oral magnesium supplement to patients is as effective as 2,000 mg of magnesium sulfate IV in preventing hypomagnesemia and arrhythmia after CABG. Thus, the authors introduce this treatment regimen as a promising and cost-effective method.

摘要
目的：心脏直视术后心律失常是一类常见临床难题，低镁血症被认为与该病症密切相关。长期以来，临床常对接受冠状动脉旁路移植术（CABG）的患者实施预防性静脉补镁干预。本研究旨在对比口服与静脉给药途径在预防术后低镁血症及心律失常中的疗效差异。

方法：本研究为一项干预性临床研究，纳入82例患者并随机分为两组。所有患者均完成基线血清镁水平检测与心律失常筛查。术前，一组患者经鼻胃（nasogastric, NG）管给予1600mg口服氢氧化镁，另一组于麻醉诱导期间给予2g硫酸镁。术后对患者血清镁水平进行连续48小时监测。两组术前低镁血症发生率差异无统计学意义（Sig: 0.576）。

结果：术中患者血清镁水平峰值约为4mg/dL，所有受试者均未出现低镁血症。尽管口服组血清镁水平曲线呈下降趋势且始终低于静脉给药组，但术后监测期间两组差异无统计学意义。此外，静脉给药组与口服组的心律失常发生率分别为13.9%与6.5%（OR: 0.428）。

结论：针对接受CABG的患者，1600mg口服补镁方案在预防术后低镁血症及心律失常方面的疗效，与2000mg静脉硫酸镁给药方案相当。据此，本研究提出该治疗方案为一种颇具前景且具备成本效益的临床干预手段。