Effects of Magnesium Sulfate on Intraoperative Blood Loss and Anesthetic Requirement in Meningioma Patients Undergoing Craniotomy with Tumor Removal: A Prospective Randomized Study

Abstract Background  Meningioma brain tumor is associated with significant blood loss. Magnesium (Mg), a calcium blocker, can facilitate blood pressure control during surgery. This study aimed to evaluate effects of magnesium on blood loss, anesthetic requirement, and its neuroprotective effect in meningioma patients undergoing craniotomy. Methods  Eighty patients aged between 18 and 70, American Society of Anesthesiologists physical status I and II, diagnosed with meningioma and scheduled for craniotomy tumor removal were randomized into two groups. Group M (Mg) received intravenous magnesium sulfate 40 mg/kg over 30 minutes initiated at skin incision and followed by continuous infusion of 10 mg/kg/h until dura closure. Group N (NSS) received 0.9% NaCl as placebo. Anesthesiologists in charge, surgeons, and patients were all blinded. The assessed outcomes were perioperative blood loss, anesthetic requirement, and pre- and postoperative neurocognitive functions assessed by Montreal Cognitive Assessment (MoCA). Results  Thirty-eight patients in each group were analyzed. In group M, the intraoperative blood losses were 500 (70, 2300) mL, and 510 (100, 1600) mL in group N ( p  = 0.315). Patients who received blood within 24 hours were 39.5% in group M and 47.4% in group N ( p  = 0.644). No differences were observed in anesthetic requirement, intraoperative mean arterial pressure, hypotensive episodes, and vasopressor usages. There were no significant differences in postoperative MoCA score. Magnesium levels did not exceed acceptable levels. Conclusions  Magnesium administration in meningioma patients had no significant effects on blood loss, anesthetic requirement, and postoperative cognitive function.