Intravenous magnesium sulfate for treating children with acute asthma in the emergency department

Benedict Griffiths, Kayleigh M Kew

Acute asthma in children can be life-threatening and must be treated promptly in the emergency setting. Intravenous magnesium sulfate is recommended by various guidelines for cases of acute asthma that have not responded to first-line treatment with bronchodilators and steroids. The treatment has recently been shown to reduce the need for hospital admission for adults compared with placebo, but it is unclear whether it is equally effective for children. To assess the safety and efficacy of intravenous magnesium sulfate (IV MgSO4) in children treated for acute asthma in the emergency department (ED). We identified studies by searching the Cochrane Airways Review Group Specialised Register up to 23 February 2016. We also searched ClinicalTrials.gov and reference lists of other reviews, and we contacted study authors to ask for additional information. We included randomised controlled trials of children treated in the ED for exacerbations of asthma if they compared any dose of IV MgSO4 with placebo. Two review authors screened the results of the search and independently extracted data from studies meeting the inclusion criteria. We resolved disagreements through discussion and contacted study authors in cases of missing data and other uncertainties relating to the studies.We analysed dichotomous data as odds ratios and continuous data as mean differences, both using fixed-effect models. We assessed each study for risk of bias and rated the quality of evidence for each outcome with GRADE and presented the results in a 'Summary of findings' table. There was insufficient evidence to conduct the planned subgroup analyses. Five studies (182 children) met the inclusion criteria, and four contributed data to at least one meta-analysis. The included studies were overall at low risk of bias, but our confidence in the evidence was generally low, mainly due to the small sample sizes. Treatment with IV MgSO4 reduced the odds of admission to hospital by 68% (odds ratio (OR) 0.32, 95% confidence interval (CI) 0.14 to 0.74; children = 115; studies = 3; I(2) = 63%). This result was based on data from just three studies including 115 children. Meta-analysis for the secondary outcomes was extremely limited by paucity of data. We performed meta-analysis for the outcome 'return to the emergency department within 48 hours', which showed a very imprecise effect estimate that was not statistically significant (OR 0.40, 95% CI 0.02 to 10.30; children = 85; studies = 2; I(2) = 0%). Side effects and adverse events were not consistently reported and meta-analysis was not possible, however few side effects or adverse events were reported. IV MgSO4 may reduce the need for hospital admission in children presenting to the ED with moderate to severe exacerbations of asthma, but the evidence is extremely limited by the number and size of studies. Few side effects of the treatment were reported, but the data were extremely limited.