Key messages
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It is unclear if magnesium sulphate, either alone or combined with other treatments, improves patient outcomes in children under two years old with bronchiolitis.
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Future large, well‐designed studies are needed looking at the benefits and harms of magnesium sulphate in acute bronchiolitis.
What is acute bronchiolitis?
Acute bronchiolitis is a common lung infection in children under two years of age. Small airways in the lungs become blocked, causing coughing, wheezing, and difficulty breathing. Bronchiolitis is caused by a virus. Usual treatment involves supportive care, which includes adequate fluids and humidified oxygen. Children with bronchiolitis may need intensive care treatment.
What did we want to find out?
We wanted to find out if magnesium sulphate, either alone or combined with other treatments, is more effective and safer compared to other treatment options for acute bronchiolitis.
What did we do?
We searched for and included studies that compared magnesium sulphate (alone or in combination with other treatments) with other treatment options. We combined the results of these studies and rated our confidence in the evidence based on study methods and sizes.
What did we find?
We included seven studies (816 children) conducted in Qatar, Turkey, Iran, China, and India. Four studies included children with moderate to severe bronchiolitis. Studies compared magnesium sulphate, given via a tube into a vein (intravenous) or as a fine inhaled spray (nebulised), with a dummy treatment (placebo), medicines to open the airways (salbutamol or epinephrine), a salt water solution (hypertonic saline), usual treatment (oxygen and adequate fluids), or no treatment.
It is unclear if magnesium sulphate alone or combined with other treatments improves outcomes such as reduced deaths, unexpected medical problems during treatment, time spent in hospital, or illness severity (based on doctors' clinical assessment scores). Time taken to recover was not measured.
What are the limitations of the evidence?
Overall, we have very low confidence in the evidence, mainly because the included studies involved few children, and there were problems with the study methods. Further research is likely to change the results of this review.
How up-to-date is the evidence?
The evidence is current to November 2024.
Read the full abstract
Acute bronchiolitis is a significant burden on children, their families and healthcare facilities. It mostly affects children younger than two years of age. Treatment involves adequate hydration, humidified oxygen supplementation, and nebulisation of medications, such as salbutamol, epinephrine, and hypertonic saline. The effectiveness of magnesium sulphate for acute bronchiolitis is unclear.
Objectives
To assess the effects of magnesium sulphate in acute bronchiolitis in children under two years of age.
Search strategy
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.
Selection criteria
Randomised controlled trials (RCTs) and quasi-RCTs, comparing magnesium sulphate, alone or with another treatment, with placebo or another treatment, in children up to two years old with acute bronchiolitis. Primary outcomes were time to recovery, mortality, and adverse events. Secondary outcomes were duration of hospital stay, clinical severity score at 0 to 24 hours and 25 to 48 hours after treatment, pulmonary function test, hospital readmission within 30 days, duration of mechanical ventilation, and duration of intensive care unit stay.
Data collection and analysis
We used standard methodological procedures expected by Cochrane. We used GRADE methods to assess the certainty of the evidence.
Main results
We included four RCTs (564 children). One study received funding from a hospital and one from a university; two studies did not report funding sources. Comparator interventions differed among all four trials. Studies were conducted in Qatar, Turkey, Iran, and India. We assessed two studies to be at an overall low risk of bias, and two to be at unclear risk of bias, overall. The certainty of the evidence for all outcomes and comparisons was very low except for one: hospital re-admission rate within 30 days of discharge for magnesium sulphate versus placebo. None of the studies measured time to recovery, duration of mechanical ventilation, duration of intensive care unit stay, or pulmonary function.
There were no events of mortality or adverse effects for magnesium sulphate compared with placebo (1 RCT, 160 children). The effects of magnesium sulphate on clinical severity are uncertain (at 0 to 24 hours: mean difference (MD) on the Wang score 0.13, 95% confidence interval (CI) -0.28 to 0.54; and at 25 to 48 hours: MD on the Wang score -0.42, 95% CI -0.84 to -0.00). Magnesium sulphate may increase hospital re-admission rate within 30 days of discharge (risk ratio (RR) 3.16, 95% CI 1.20 to 8.27; 158 children; low-certainty evidence).
None of our primary outcomes were measured for magnesium sulphate compared with hypertonic saline (1 RCT, 220 children). Effects were uncertain on the duration of hospital stay in days (MD 0.00, 95% CI -0.28 to 0.28), and on 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).
There were no events of mortality or adverse effects for magnesium sulphate, with or without salbutamol, compared with salbutamol (1 RCT, 57 children). Effects on the duration of hospital stay were uncertain (magnesium sulphate: 24 hours (95% CI 25.8 to 47.4), magnesium sulphate + salbutamol: 20 hours (95% CI 15.3 to 39.0), and salbutamol: 24 hours (95% CI 23.4 to 76.9)).
None of our primary outcomes were measured for magnesium sulphate + epinephrine compared with no treatment or normal saline + epinephrine (1 RCT,120 children). Effects were uncertain for the duration of hospital stay in hours (MD -0.40, 95% CI -3.94 to 3.14), and for RDAI scores (0 to 24 hours: MD -0.20, 95% CI -1.06 to 0.66; and 25 to 48 hours: MD -0.90, 95% CI -1.75 to -0.05).
Authors' conclusions
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.
Funding
No funding was received for this review.
Registration
Protocol (2018): doi.org/10.1002/14651858.CD012965
Original review (2020): doi.org/10.1002/14651858.CD012965.pub2
