Pharmacokinetic-guided magnesium prophylaxis in cardiac surgery: A randomized trial demonstrating guideline-level reductions in atrial fibrillation, accelerated recovery, and systemic cost savings

Abstract Objective To evaluate the efficacy, safety, and cost-effectiveness of a perioperative magnesium (Mg) sulfate protocol in reducing postoperative atrial fibrillation (AF) incidence and ICU resource strain following cardiac surgery. Methods Design: Double-blind, single-center randomized controlled trial (RCT). Setting: Tertiary-care academic hospital. Participants: 130 adults undergoing elective cardiac surgery, randomized to Mg sulfate (n=65) or placebo (n=65). Interventions: The Mg group received a pharmacokinetic-guided regimen: 2 g intravenous bolus post-cardiopulmonary bypass, followed by 1 g/h infusion for 5 hours, then 200 mg/h for 19 hours, and oral supplementation (I g every 8 hours) for one week post-discharge. The placebo group received equivalent saline infusions and oral placebo. Results Primary outcome: AF incidence was 18. 5% in the Mg group vs. 41. 5% in placebo (unadjusted RR=0. 45, 95% CI: 0. 25–0. 81; p=0. 007). Secondary outcomes: Mg shortened ICU stay by 1. 4 days (p<0. 001), reduced mechanical ventilation duration by 3. 2 hours (p<0. 001), and demonstrated comparable safety profiles for hypotension and renal impairment. Subgroup analysis: CABG patients showed 65% risk reduction (OR=0. 35, p=0. 01). Cost-effectiveness: ICU stay reduction projected 3, 500 savings per patient. Conclusions Perioperative Mg sulfate significantly reduces AF incidence, accelerates recovery, and lowers healthcare costs, supporting its integration into standardized postoperative protocols. This trial provides Level I evidence for Mg as a guideline-recommended intervention. These findings are promising and support the integration of Mg into standardized postoperative protocols; however, they require confirmation in larger, multicenter studies.