Beneficial effect of intravenous magnesium during endoscopic submucosal dissection for gastric neoplasm

Background: Endoscopic submucosal dissection (ESD) has been revealed as an effective treatment of early gastric neoplasm and should be performed under sedation with adequate pain control. Magnesium sulfate has analgesic, sedative, and sympatholytic properties. This study examined the effects of intravenous magnesium 50 mg/kg administered before ESD for gastric neoplasm on analgesic and sedative consumptions during ESD and pain after ESD. Methods: In this randomized, double-blind, and prospective study, patients undergoing ESD randomly received either intravenous magnesium sulfate 50 mg/kg (magnesium group n = 30) or the same volume of normal saline (control group n = 30) over 10 min before the start of sedation. Fentanyl consumption during ESD was the primary end point. Hemodynamics was recorded during the procedure, and abdominal pain was evaluated at 30 min, 6 h, and 24 h after ESD. Results: During ESD, fentanyl consumption was 24 % less in the magnesium group than in the control group (96 ± 27 vs. 126 ± 41 μg, mean ± SD; p = 0.002), although there was no significant difference in propofol consumption (p = 0.317). In addition, magnesium attenuated the elevation of mean blood pressure at the time of epinephrine submucosal injection (p = 0.038) and 5 min after submucosal dissection (p = 0.004). Less patients of the magnesium group compared to the control group requested for additional analgesics in the recovery room (14 vs. 38 %, p = 0.043), and the intensity of abdominal pain was lower at 30 min after ESD in the magnesium group (p = 0.034). Conclusions: A single-dose intravenous administration of magnesium 50 mg/kg before sedation reduced analgesic requirements both during and after ESD for gastric neoplasm without adverse effects. In addition, magnesium contributed to stable hemodynamics throughout the procedure.