Non-invasive positive pressure ventilation for acute asthma in children

Asthma is one of the most common reasons for hospital admission among children, with significant economic burden and impact on quality of life. Non-invasive positive pressure ventilation (NPPV) is increasingly used in the care of children with acute asthma, although the evidence supporting it is weak, and clinical guidelines do not offer any recommendations on its routine use. However, NPPV might be an effective way to improve outcomes for some children with asthma. A previous review did not demonstrate a clear benefit, but was limited by few studies with small sample sizes. This is an update of the previous review.

To assess the benefits and harms of NPPV as an add-on therapy to usual care (e.g. bronchodilators and corticosteroids) in children (< 18 years) with acute asthma.

We searched the Cochrane Airways Group Specialised Register, CENTRAL, MEDLINE, and Embase. We also conducted a search of ClinicalTrials.gov and the WHO ICTRP. We searched all databases from their inception to March 2023, with no restrictions on language of publication.

We included randomised clinical trials (RCTs) assessing NPPV as add-on therapy to usual care versus usual care for children hospitalised for acute asthma exacerbations.

We used standard Cochrane methods.

We included three RCTs randomising 60 children with acute asthma to NPPV and 60 children to control. All included trials assessed the effects of bilevel positive airway pressure (BiPAP) for acute asthma in a paediatric intensive care unit (PICU) setting. None of the trials used continuous positive airway pressure (CPAP). The controls received standard care. The median age of children ranged from three to six years, and asthma severity ranged from moderate to severe. Our primary outcome measures were all-cause mortality, serious adverse events, and asthma symptom score. Secondary outcomes were non-serious adverse events, health-related quality of life, arterial blood gases and pH, pneumonia, cost, and PICU length of stay. None of the trials reported any deaths or serious adverse events (except one trial that reported intubation rate). Two trials reported asthma symptom score, each demonstrating reductions in asthma symptoms in the BiPAP group. In one trial, the asthma symptom score was (mean difference (MD) -2.50, 95% confidence interval (CI) -4.70 to -0.30, P = 0.03; 19 children) lower in the BiPAP group. In the other trial, a cross-over trial, BiPAP was associated with a lower mean asthma symptom score (MD -3.7; 16 children; very low certainty evidence) before cross-over, but investigators did not report a standard deviation, and it could not be estimated from the first phase of the trial before cross-over. The reduction in both trials was above our predefined minimal important difference. Overall, NPPV with standard care may reduce asthma symptom score compared to standard care alone, but the evidence is very uncertain. The only reported serious adverse event was intubation rate in one trial. The trial had an intubation rate of 40% and showed that BiPAP may result in a large reduction in intubation rate (risk ratio 0.47, 95% CI 0.23 to 0.95; 78 children), but the evidence is very uncertain. Post hoc analysis showed that BiPAP may result in a slight decrease in length of PICU stay (MD -0.87 day, 95% CI -1.52 to -0.22; 100 children), but the evidence is very uncertain. Meta-analysis or Trial Sequential Analysis was not possible because of insufficient reporting and different scoring systems. All three trials had high risk of bias with serious imprecision of results, leading to very low certainty of evidence.

The currently available evidence for NNPV is uncertain. NPPV may lead to an improvement in asthma symptom score, decreased intubation rate, and slightly shorter PICU stay; however, the evidence is of very low certainty. Larger RCTs with low risk of bias are warranted.