Effect of perioperative magnesium sulfate on neurological outcome in neurosurgical patients: a randomized double-blind controlled trial.

Background: Supplemental magnesium sulfate has a potential neuroprotective role in acute brain injury. It is safe, widely available, and inexpensive. This study evaluated the effect of perioperative intravenous administration of magnesium sulfate on brain damage caused by neurosurgery.

Methods: Prospective randomized double-blind controlled study. Fifty adult patients undergoing supratentorial neurosurgery (25 were assigned to magnesium sulfate group and 26 to the control group). On arrival to the operating room, the intervention group received intravenous magnesium sulfate, 4 g bolus in 100 mL of 0.9% saline solution lasting 20 min followed by 20 g in 1000 mL saline lasting 24 h. The control group received the same volume of saline. Serum S100B-protein levels 2 h after surgery was the primary outcome. Secondary outcomes were neuron-specific enolase, magnetic resonance imaging (MRI) parameters, neuropsychological testing, Glasgow Outcome Scale, and mortality, during hospital stay and at six and 12 months after surgery.

Results: Statistically significant differences in the primary outcome were not found. At six months, MRI showed a mean surgical cavity volume of 10.0 cm³ (95% confidence interval [CI] 4.4-15.6) in the magnesium group vs. 26.9 cm³ (95% CI 13.8-39.9) in controls (P=0.02), gliosis/edema in 55% vs. 90.5% (P=0.014), and contrast enhancement around the cavity in 33.3% vs. 80% (P=0.041), respectively. Patients in the magnesium group showed better scores in some neuropsychological tests. There were no relevant adverse effects in magnesium group.

Conclusions: Neurosurgical patients treated with supplemental magnesium sulfate showed macroscopic improvement in some MRI parameters related to blood-brain barrier permeability and better performance in some focal cognitive domain.