Magnesium sulphate for treating acute bronchiolitis in children under two years of age

The effectiveness of magnesium sulphate for acute bronchiolitis in children under two years is unclear. There is a paucity of robust data favouring or opposing the use of magnesium sulphate in acute bronchiolitis. This is an update of a review first published in 2020.

To assess the effects of magnesium sulphate in acute bronchiolitis in children under two years of age.

We searched CENTRAL, MEDLINE, Embase, LILACS, CINAHL, and two trial registries until 23 November 2024. We contacted trial authors and searched conference proceedings and reference lists of retrieved articles to identify additional studies. Both unpublished and published studies were eligible for inclusion.

Randomised controlled trials (RCTs) and non-randomised studies of magnesium sulphate (alone or with another treatment) compared with placebo or another treatment, in children under two years with acute bronchiolitis.

Our critical outcomes were time to recovery; all-cause, in-hospital mortality; and adverse events. Important outcomes included duration of hospital stay, clinical severity score at 0 to 24 hours and at 25 to 48 hours after treatment, and hospital readmission rate within 30 days of discharge.

We assessed risk of bias using Cochrane's RoB 1 tool.

We planned a priori to use a random-effects model for meta-analysis, but used a fixed-effect model when only a single study was available. We used standard methodological procedures expected by Cochrane. We used GRADE to assess the certainty of the evidence.

We identified three new trials for a total of seven trials (816 children) in this update. One study each received funding from a hospital, university, and funding agency; one study did not receive any funding; and three studies did not report funding sources. Comparator interventions were placebo, nebulised hypertonic saline, epinephrine, salbutamol, and standard care (humidified oxygen and hydration). The included studies were conducted in Qatar, Turkey, Iran, China, and India. We identified one study as an erratum that was unlikely to have affected the validity of the results.

None of the studies measured time to recovery. The certainty of evidence was very low for most outcomes due to risk of bias and very serious imprecision. Magnesium sulphate compared with placebo (1 RCT, 160 children) The effects of magnesium sulphate on mortality or adverse events (no events in either intervention; risk ratio (RR) not estimable), duration of hospital stay (mean difference (MD) not estimable), or clinical severity (Wang score) (at 0 to 24 hours: MD 0.13, 95% confidence interval (CI) -0.28 to 0.54; at 25 to 48 hours: MD -0.42, 95% CI -0.84 to -0.00) are very uncertain. Magnesium sulphate may increase hospital readmission rates within 30 days of discharge (RR 3.16, 95% CI 1.20 to 8.27; 158 children; low-certainty evidence). Other outcomes were not measured. Magnesium sulphate compared with hypertonic saline (1 RCT, 220 children) Mortality and adverse events were not measured. The effects of magnesium sulphate on duration of hospital stay (days) (MD 0.00, 95% CI -0.28 to 0.28) or clinical severity on the Respiratory Distress Assessment Instrument (RDAI) score at 25 to 48 hours (MD 0.10, 95% CI -0.39 to 0.59) are very uncertain. Other outcomes were not measured. No studies compared magnesium sulphate with epinephrine. Magnesium sulphate compared with conventional bronchodilator (salbutamol) (1 RCT, 37 children) The effects of magnesium sulphate on mortality or adverse events (no events in either intervention; RR not estimable) or duration of hospital stay (magnesium sulphate: 24 hours (95% CI 25.8 to 47.4); salbutamol: 24 hours (95% CI 23.4 to 76.9)) are very uncertain. Other outcomes were not measured. Magnesium sulphate + bronchodilator compared with no treatment or normal saline + the same bronchodilator (1 RCT, 37 children) The bronchodilator used was salbutamol. The effects of magnesium sulphate on mortality or adverse events (no events in either intervention; RR not estimable) or duration of hospital stay (magnesium sulphate + salbutamol: 20 hours (95% CI 15.3 to 39.0); salbutamol: 24 hours (95% CI 23.4 to 76.9)) are very uncertain. Other outcomes were not measured. No studies compared magnesium sulphate + hypertonic saline with no treatment or normal saline + hypertonic saline. Magnesium sulphate + epinephrine compared with no treatment or normal saline + epinephrine (1 RCT, 120 children) Mortality and adverse events were not measured. The effects of magnesium sulphate on duration of hospital stay (hours) (MD -0.40, 95% CI -3.94 to 3.14) or clinical severity (RDAI scores) (0 to 24 hours: MD -0.20, 95% CI -1.06 to 0.66; 25 to 48 hours: MD -0.90, 95% CI -1.75 to -0.05) are very uncertain. Other outcomes were not measured. Magnesium sulphate + standard care compared with standard care (2 RCTs, 164 children) Mortality was not measured. The effects of magnesium sulphate on adverse events (no events in either intervention; RR not estimable; 2 RCTs, 164 children), duration of hospital stay (days) (MD -0.07, 95% CI -1.12 to 0.98; 1 RCT, 60 children), clinical severity (Wang and RDAI scores) (at 0 to 24 hours: MD -0.65, 95% CI -1.71 to 0.42; 2 RCTs, 164 children), or hospital readmission rates within 30 days of discharge (RR 3.41, 95% CI 0.14 to 80.59; 1 RCT, 60 children) are very uncertain. Other outcomes were not measured.

The available evidence is insufficient to establish the benefits and harms of magnesium sulphate for treating children under two years of age with acute bronchiolitis. There was no information on time to recovery and little information on mortality and adverse events. Well-designed RCTs studying the effects of magnesium sulphate in acute bronchiolitis are needed. Outcomes such as time to recovery, adverse events, and duration of hospital stay should be measured.

No funding was received for this review.

Protocol (2018): doi.org/10.1002/14651858.CD012965 Original review (2020): doi.org/10.1002/14651858.CD012965.pub2.