Abstract: We included three studies with a total of 122 children (62/60 in intervention/control arms) aged up to 12 months that investigated nasal CPAP compared with supportive (or "standard") therapy. We included one new trial (72 children) that contributed data to the assessment of respiratory rate and need for mechanical ventilation for this update. The included studies were single-centre trials conducted in France, the UK, and India. Two studies were parallel-group RCTs and one was a cross-over RCT. The evidence provided by the included studies was low quality; we assessed high risk of bias for blinding, incomplete outcome data, and selective reporting, and confidence intervals were wide. The effect of CPAP on the need for mechanical ventilation in children with acute bronchiolitis was uncertain due to imprecision around the effect estimate (3 RCTs, 122 children; risk ratio (RR) 0.69, 95% confidence interval (CI) 0.14 to 3.36; low-quality evidence). None of the trials measured time to recovery. Limited, low-quality evidence indicated that CPAP decreased respiratory rate (2 RCTs, 91 children; mean difference (MD) -3.81, 95% CI -5.78 to -1.84). Only one trial measured change in arterial oxygen saturation, and the results were imprecise (19 children; MD -1.70%, 95% CI -3.76 to 0.36). The effect of CPAP on change in arterial partial carbon dioxide pressure (pCO₂) was imprecise (2 RCTs, 50 children; MD -2.62 mmHg, 95% CI -5.29 to 0.05; low-quality evidence). Duration of hospital stay was similar in both CPAP and supportive care groups (2 RCTs, 50 children; MD 0.07 days, 95% CI -0.36 to 0.50; low-quality evidence). Two studies did not report about pneumothorax, but pneumothorax did not occur in one study. No studies reported occurrences of deaths. Several outcomes (change in partial oxygen pressure, hospital admission rate (from emergency department to hospital), duration of emergency department stay, and need for intensive care unit admission) were not reported in the included studies. Limited, low-quality evidence suggests that breathing improved (a decreased respiratory rate) in children with bronchiolitis who received CPAP; this finding is unchanged from the 2015 review. Further evidence for this outcome was provided by the inclusion of a low-quality study for the 2018 update. Due to the limited available evidence, the effect of CPAP in children with acute bronchiolitis is uncertain for other outcomes. Larger, adequately powered trials are needed to evaluate the effect of CPAP for children with acute bronchiolitis.

Plain-language summary: We included three small randomised controlled trials (studies in which participants are assigned to one of two or more treatment groups using a random method) involving a total of 122 children aged up to 12 months who were diagnosed with bronchiolitis. We included one new low-quality trial with 72 children in this update. The three studies were conducted at single centres in France, the UK, and India. All studies compared CPAP with standard therapy. One study was funded by a university hospital; one reported that no funding was received; and one did not mention the funding source. Insufficient evidence was available to permit conclusions about the effect of CPAP on the need for mechanical ventilation in children with bronchiolitis. Limited, low-quality evidence indicated that breathing improved (respiratory rate decreased) in children who received CPAP. The length of time children spent in hospital was similar between the CPAP and the standard therapy groups. No children in the studies were reported to have died. The studies did not report on time to recovery, change in partial oxygen pressure, how often children were admitted to hospital from the emergency department, how long children were in the emergency department, and the need for intensive care admission. There were no local nasal effects, or shock as reported by one study. No children were reported to have had air in the cavity between the lungs and the chest wall, causing lung collapse (pneumothorax) as reported by one study. Two studies did not report about local nasal effects, shock, or pneumothorax. The study added for this update contributed data to the assessment of respiratory rate and need for mechanical ventilation. We found limited, low-quality evidence related to CPAP for children with bronchiolitis. Evidence quality was reduced due to high risk of bias, losses to follow-up, selective reporting, and the wide range of values reported by the included studies.