Protocol for a Group-Sequential Two-Stratum Multicenter Open-Label Randomized Clinical Trial of Respiratory Support in Infants With Acute Bronchiolitis: Breathing Assistance in Children With Bronchiolitis (BACHb).

OBJECTIVES: The Breathing Assistance in Children with bronchiolitis (BACHb) trial aims to evaluate the clinical and cost-effectiveness of high-flow nasal cannula (HFNC) therapy compared with humidified standard oxygen (HSO) in infants with moderate bronchiolitis, and HFNC with continuous positive airway pressure (CPAP) in severe bronchiolitis. DESIGN: Pragmatic, group-sequential, two-stratum, multicenter, open-label randomized clinical trial. SETTING: Fifty hospitals across England, Scotland, and Wales. PATIENTS: Hospitalized infants younger than 12 months old with a clinical diagnosis of bronchiolitis, assessed at least twice 15 minutes apart to fulfill criteria for either severe bronchiolitis (one or more of: respiratory rate > 70 breaths/min, grunting, marked chest recession, recurrent short apneas) or moderate bronchiolitis (lack of response to low-flow oxygen, indicated by persistent hypoxemia and/or moderate respiratory distress). INTERVENTIONS: "Moderate bronchiolitis stratum": HFNC at a flow rate of 2 L/kg/min vs. HSO through a facemask or headbox at a flow rate up to 15 L/min. "Severe bronchiolitis stratum": HFNC at a flow rate of 2 L/kg/min vs. CPAP pressure set at 6-8 cm H2O. MEASUREMENTS AND MAIN RESULTS: In each stratum, eligible infants will be randomly allocated on a 1:1 basis to the trial treatments using a web-based system by permuted block randomization, stratified by site of recruitment and age (< 6 wk and ≥ 6 wk). Due to the emergency nature of the treatments, written informed consent will be deferred. The primary outcome is time from randomization to hospital discharge within 30 days. Baseline clinical characteristics and hospital course, including details of respiratory support, and discharge and cost-effectiveness outcomes will be collected. The trial received Health Research Authority and Research Ethics Committee approval from the Yorkshire and The Humber-South Yorkshire Research Ethics Committee on August 3, 2023 (reference: 23/YH/0166). The trial registration is ISRCTN52937119. CONCLUSIONS: Trial findings will be disseminated in national and international conferences, in peer-reviewed journals and through social media.