Magnesium and Esophageal Pain After Peroral Endoscopic Myotomy of the Esophagus: A Randomized, Double-Blind, Placebo-Controlled Trial.

Background: Postoperative esophageal pain occurs in 67% of patients after peroral endoscopic esophageal myotomy (POEM). Magnesium can act as a smooth muscle relaxant. This study investigated whether intraoperative magnesium can reduce postoperative esophageal pain in patients undergoing POEM.

Methods: In this double-blind, placebo-controlled trial, 92 patients were randomized to receive either magnesium sulfate as a 50 mg.kg -1 (total body weight) bolus followed by an infusion at 25 mg.kg -1 .hr -1 , or 0.9% saline. Intraoperative analgesia was standardized in all patients. The primary outcome was the score from a validated, modified Esophageal Symptoms Questionnaire (ESQ) in the postanesthesia care unit (PACU). Pain scores, opioid requirements, and questionnaire scores were collected through postoperative day 1.

Results: ESQ scores were significantly lower in the magnesium group in the PACU (median [25th-75th], 24 [18-31] vs 35 [28-42]; median difference [95% confidence interval, CI], 10 [6-13]; P < .0001) and on postoperative day 1 (16 [14-23] vs 30 [24-35]; P < .0001). Less opioids were needed in the magnesium group in the PACU (mean ± standard deviation [SD] [99% CI], 4.7 ± 10 [1-9] mg vs 29 ± 21 [21-37] mg; P < .0001) and on postoperative day 1 (1 ± 3.7 [0-2.5] mg vs 13 ± 23 [4-23] mg; P = .0009). Pain scores were lower in the magnesium group in the PACU (0 [0-3] vs 5 [5-7]; P < .0001) and on postoperative day 1 (0 [0-2] vs 4 [3-5]; P < .0001).

Conclusions: Patients undergoing POEM randomized to receive intraoperative magnesium had sustained reductions in esophageal discomfort severity and opioid requirements 24 hours after surgery.