Effectiveness of Combined versus Single Circadian Interventions in Pediatric Intensive Care Units: a Systematic Review Protocol Protocol for a Systematic Review of Circadian Interventions in PICUs

BackgroundCircadian rhythms regulate fundamental biological processes such as sleep- wake cycles, hormonal secretion, immune function, and cellular repair. In pediatric intensive care units (PICUs), these rhythms are highly vulnerable to disruption from constant artificial lighting, frequent procedures, environmental noise, and irregular feeding schedules. Critically ill children are particularly at risk due to their still-developing circadian systems, and disruption has been linked to poorer sleep quality, and delayed recovery. Although interventions such as light therapy, noise reduction, and structured sleep protocols have been explored, the comparative benefits of combining multiple circadian interventions versus applying them in isolation remain unclear. ObjectiveThis protocol outlines the methodology for a systematic review to evaluate the effectiveness of combined versus single-component circadian interventions in improving clinical outcomes, circadian alignment, sleep quality, and overall well-being in patients admitted to PICUs. MethodsFollowing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines, we will search PubMed, Web of Science, Scopus, Embase, CINAHL, and the Cochrane Library from January 2020 to September 2025. Eligible studies will include randomized controlled trials, quasi-experimental studies, and observational designs evaluating circadian interventions among patients aged 0-18 years in PICUs. Two independent reviewers will screen records, extract data, and assess risk of bias using RoB 2 for RCTs and ROBINS-I for non-randomized studies. Narrative synthesis will be the primary analysis method; if data permit, meta-analysis will be conducted using random-effects models. Primary outcomes will include circadian measures, sleep parameters, and clinical outcomes such as length of stay and delirium incidence. Subgroup, sensitivity, and, if feasible, meta-regression analyses will be performed. DiscussionFindings will inform clinical strategies to protect circadian function in critically ill children and may guide PICU environmental and care protocols. RegistrationThis protocol is registered with the Open Science Framework (DOI: 10.17605/OSF.IO/8SPZM) and PROSPERO (CRD4201091137).