Effectiveness of combined versus single circadian interventions in neonatal and pediatric intensive care units: a systematic review with meta-analysis

IntroductionAdmission to neonatal or pediatric intensive care units exposes vulnerable patients to confounding environmental cues, disrupting circadian rhythms and potentially compromising physiological stability. While various circadian interventions exist, ranging from simple light cycling to complex multicomponent bundles, it remains unclear whether complex bundles offer superior clinical benefits over single-modality interventions. This systematic review evaluated the efficacy of circadian interventions on physiological parameters and sleep primarily in critically ill neonates and children, specifically comparing single versus combined strategies.MethodsA systematic review and meta-analysis were conducted following PRISMA 2020 guidelines. We searched five major electronic databases: PubMed, ScienceDirect, CINAHL, WoS, Scopus and LILACS. Additionally, the Epistemonikos and SciELO databases were screened to identify relevant studies published in languages other than English. The search covered from inception to 2025 and was conducted during October 2025. Risk of bias was assessed using the Cochrane RoB 2 tool and ROBINS-I, while the certainty of evidence was evaluated using the GRADE approach. Data were synthesized using random-effects meta-analysis for physiological outcomes and SWiM guidelines for studies with non-parametric or incompatible data.ResultsForty-one studies (N = 2,548) met the inclusion criteria. Meta-analysis of 16 studies demonstrated that circadian interventions significantly reduced heart rate (SMD -0.70; 95% CI [−1.10, −0.30]; p < 0.001) and respiratory rate (SMD −0.75; p < 0.001), while improving oxygen saturation (SMD + 1.33; p < 0.001) and increasing sleep duration (SMD + 0.92; p < 0.001). Narrative synthesis of 16 additional studies confirmed these findings, with 81.2% reporting positive outcomes. Importantly, subgroup analysis revealed no statistically significant difference between single and multicomponent interventions across any outcome (p > 0.05). The certainty of evidence was graded as low due to the inherent inability to blind environmental interventions and statistical heterogeneity.ConclusionCircadian interventions are effective strategies for modulating physiological parameters and improving sleep quality in the NICU. Single interventions, such as cycled lighting, yielded similar outcomes to complex multicomponent bundles, but due to the lack of pediatric research, our results should be interpreted with caution. Future research should prioritize primary research in pediatric settings to deepen our understanding about circadian interventions.Systematic review registrationhttps://doi.org/10.17605/OSF.IO/8SPZM, Identifier: CRD4201091137.