Authors: Kong H. et al.
Anesthesiology, October 3, 2025. DOI: 10.1097/ALN.0000000000005778
This randomized, double-blind clinical trial investigated whether preemptive magnesium sulfate infusion could improve intraoperative hemodynamic stability during pheochromocytoma and paraganglioma (PPGL) resection—a surgery characterized by extreme fluctuations in blood pressure and heart rate due to catecholamine surges. Despite magnesium’s known sympatholytic and vasodilatory properties, high-quality prospective evidence in PPGL surgery has been limited.
Ninety-two patients scheduled for PPGL resection were randomized to receive either magnesium sulfate (loading dose 50 mg/kg, followed by 15 mg/kg/hr infusion) or placebo (normal saline), starting 30 minutes before incision and discontinued after tumor removal. The primary outcome was the percentage of total anesthesia time spent outside defined hemodynamic targets: systolic arterial pressure (SAP) >160 mmHg, mean arterial pressure (MAP) <60 mmHg, or heart rate (HR) >100 bpm.
Magnesium sulfate significantly reduced intraoperative hemodynamic instability compared with placebo. The median time outside target ranges was 4.3% versus 8.3% (P = 0.003). Maximum SAP was lower in the magnesium group (185 vs. 196 mmHg, P < 0.001), as were the proportion of patients requiring phentolamine (66% vs. 89%, P = 0.011) and total phentolamine dose (3 mg vs. 9 mg, P = 0.011). Plasma magnesium concentrations peaked at safe therapeutic levels (~1.8 mmol/L), and there were no significant differences in adverse events between groups.
These findings demonstrate that magnesium sulfate—administered prophylactically before and during surgery—attenuates the severity and frequency of hypertensive and tachycardic episodes in PPGL resection, reducing the need for intraoperative vasodilators without compromising safety.
What You Should Know
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Preemptive magnesium sulfate infusion improves intraoperative blood pressure and heart rate stability during PPGL surgery.
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The magnesium group spent roughly half as much time outside target hemodynamic ranges as the placebo group.
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Fewer patients required rescue phentolamine, and doses were significantly lower.
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No safety concerns were identified, suggesting clinical feasibility for perioperative use.
Thank you to Anesthesiology for publishing this rigorous trial demonstrating that magnesium sulfate safely enhances hemodynamic control during pheochromocytoma and paraganglioma resection.