Intravenous magnesium therapy in adult patients with an aneurysmal subarachnoid haemorrhage: a systematic review and meta-analysis

Background: The value of magnesium for the prevention of cerebral arterial vasospasm in patients with aneurysmal subarachnoid haemorrhage (SAH) is debatable. We performed a systematic review to collate the available evidence to evaluate the effects of intravenous magnesium for the prevention of cerebral arterial vasospasm.

Materials and methods: An electronic search of MEDLINE (Ovid), ProQuest, CINAHL and the Cochrane Database of Systematic Reviews was undertaken up to 1st October 2012 for randomised controlled trials (RCTs) of intravenous magnesium for the prevention of vasospasm in adult patients with aneurysmal SAH. Primary outcome measures were risk of vasospasm, functional outcomes and mortality. Results are presented as risk ratios (RR) and 95% confidence intervals (CI).

Results: Nine of 38 trials were included in this review. Not all trials could be combined for analyses due to differences in reported outcomes and outcome definitions. Of the trials that could be combined we found a statistically significant reduction on the incidence of vasospasm with magnesium (RR 0.83; 95% CI 0.71, 0.98; P=0.03). No statistical difference for the last reported favourable functional outcome (RR 1.00; 95% CI 0.96, 1.05; P=0.84); or mortality (RR 0.95; 95% CI 0.77, 1.18; P=0.67) between magnesium treated and standard care/control groups was found.

Conclusion: We identified a benefit in the role of magnesium to reduce the incidence of cerebral vasospasm in patients with an aneurysmal SAH. However no benefit was found regarding improved favourable functional outcome or a reduction of mortality.