Prone Positioning in Infants With Acute Bronchiolitis: The PROPOSITIS Randomized Clinical Trial

Prone positioning has been shown to improve respiratory mechanics and oxygenation, but its clinical benefit in infants with acute viral bronchiolitis receiving high-flow nasal cannula (HFNC) support remains unknown.

To investigate whether prone positioning in infants with moderate to severe acute bronchiolitis and HFNC support reduces escalation to noninvasive or invasive ventilation.

Multicenter, randomized, open-label trial conducted in 15 pediatric intermediate or intensive care units in France. Infants aged 6 months or younger admitted for 24 hours or less with a diagnosis of acute bronchiolitis with moderate to severe respiratory distress requiring HFNC support were enrolled between January 2021 and November 2023 and followed up until hospital discharge (last patient discharged on December 11, 2023).

Participants were randomly assigned to the prone position (n = 221) or supine position (n = 230). Infants in the prone position group received prone positioning for 24 hours or longer during the first 48 hours. All participants received standardized HFNC support at 2 L/kg/min.

The primary outcome was the need for escalation of care to noninvasive or invasive ventilation within the first 72 hours, according to prespecified criteria. Secondary outcomes included treatment failure, determined by an independent clinical adjudication committee; tolerance of prone positioning; length of hospital stay; duration of respiratory support; infant comfort; and adverse events.

Among 451 infants randomized, 446 were included in the primary analysis (median age, 41 [IQR, 19-72] days; 54% male). Escalation of care occurred in 80 infants (17.9%), with no significant difference between the prone position (33/220 [15.0%]) and supine position (47/226 [20.8%]) groups (adjusted odds ratio, 0.66 [95% CI, 0.40-1.07]; P = .09). Secondary outcomes did not differ significantly between the 2 groups. In the safety analysis, serious adverse events occurred in 2 of 180 infants (1.1%) in the prone position group and 2 of 264 (0.8%) in the supine position group.

Prone positioning in infants with moderate to severe bronchiolitis receiving HFNC support did not significantly reduce escalation of care. However, the wide 95% confidence interval around the observed odds ratio suggests that this study was not definitive and further research is warranted.

ClinicalTrials.gov Identifier: NCT03976895.