Contextual factors influencing bubble continuous positive airway pressure implementation for paediatric respiratory distress in low-income and middle-income countries: a realist review

Background: Bubble continuous positive airway pressure (bCPAP) is a low-cost, non-invasive respiratory support therapy for children with respiratory distress, but its effectiveness is dependent on the context. We aimed to understand contextual factors influencing bCPAP implementation for children aged 1–59 months in low-income and middle-income countries (LMICs) and to develop a theory explaining how these factors influence implementation outcomes. Methods: In this realist review, we generated an initial programme theory comprising candidate context–mechanism–outcome configurations (CMOCs) via review of key references and team discussion. On July 25, 2023, we conducted a search for peer-reviewed and grey literature, without date restrictions, describing bCPAP use for paediatric respiratory distress in LMICs. We included references describing related contexts, mechanisms, or outcomes. We coded statements from the literature supporting each CMOC, iteratively revising and adding CMOCs using inductive and deductive logic. We assembled an international, interdisciplinary panel of 22 bCPAP stakeholders to refine CMOCs using iterative surveys, focus groups, and interviews until we reached thematic saturation. This realist review is registered with PROSPERO (CRD42023403584). Findings: Of 1640 peer-reviewed references and eight grey literature references retrieved, 38 peer-reviewed articles and two grey literature documents were deemed eligible for inclusion after removal of duplicates and screening. After four rounds of expert surveys and three focus groups, we identified 18 CMOCs. CMOCs were synthesised into a final programme theory operating at five levels to influence implementation feasibility, fidelity, and sustainability: (1) the bCPAP device, (2) local partnerships and infrastructure, (3) clinical and technical teams, (4) caregivers and the community, and (5) institutional practices. Interpretation: Using realist methods with a diverse, international stakeholder panel, we generated a theory that could explain how bCPAP therapy works in different contexts. This theory could be leveraged to enhance the rigour of future bCPAP implementation trials. Funding: Yale National Clinician Scholars Program, US National Center for Advancing Translational Science (TL1TR001864), and National Heart, Lung, and Blood Institute (T32HL155000).