Perioperative magnesium sulfate : an adjuvant to patients undergoing video-assisted thoracoscopic surgery

Background This randomized, prospective, double-blind, placebo-controlled study was designed to assess perioperative magnesium sulfate, an N-methyl-d-aspartate receptor blocker, as an anesthetic adjuvant reducing intraoperative anesthetic requirement, with a decrease in postoperative analgesic requirement and less adverse events. Patients and methods A total of 24 patients undergoing video-assisted thoracoscopic surgery were included in two parallel groups − the magnesium group (group M, n=12) received magnesium sulfate 40 mg/kg intravenously before induction of anesthesia followed by 15 mg/kg/h continuous intravenous infusion during the operation. The same volume of isotonic solution was administered to the control group (group C, n=12). Primary outcome measures were postoperative analgesic requirement (doses of morphine and ketorolac). Secondary outcomes included intraoperative anesthetic requirements (fentanyl, sevoflurane, and vecuronium), postoperative visual analog score, Ramsay sedation score, and postoperative adverse events. Results In the magnesium group, there was a reduction in intraoperative fentanyl (P=0.01), sevoflurane (P=0.02), and vecuronium (P=0.008), with a significant reduction in the postoperative dose of morphine (P=0.02), the need for rescue ketorolac (P=0.02), and a significant reduction in visual analog score and Ramsay sedation score compared with group C at 2, 3, 4, 6, and 8 h. There was a significant reduction in the number of patients who suffered an episode of tachyarrhythmia (P=0.03) with a decrease in nausea (P=0.06), vomiting (P=0.06), and pruritus (P=0.3), but did not reach statistical significance in group M compared with group C. Conclusion Magnesium sulfate as an anesthetic adjuvant decreased postoperative analgesic requirement with a decrease in intraoperative anesthetic doses, with less adverse events.