Non-pharmacological ICU nursing interventions and melatonin concentrations: a systematic review and meta-analysis of randomized controlled trials
Abstract
Background: Sleep disruption and circadian dysregulation are common in patients admitted to the intensive care unit (ICU) and are associated with adverse recovery outcomes. Non-pharmacological nursing strategies such as environmental control and clustered care are widely implemented to reduce nocturnal disturbance, yet their physiological effects remain uncertain. Melatonin may serve as a potential marker of circadian processes; however, its interpretation depends on temporal dynamics that are not consistently captured across studies.
Methods: This systematic review and meta-analysis of randomized controlled trials evaluated the effects of non-pharmacological ICU nursing interventions on melatonin concentrations, with secondary analyses of cortisol levels and sleep quality. PubMed, Embase, Web of Science, Scopus, and the Cochrane Library were searched from inception to February 7, 2026. Random-effects meta-analysis using Hedges' g was performed. Risk of bias was assessed using the Cochrane RoB 2.0 tool and certainty of evidence using GRADE. The review was prospectively registered in PROSPERO (CRD420261303901) in February 2026.
Results: Five randomized trials were included. Non-pharmacological nursing interventions were associated with higher measured melatonin concentrations compared with usual care (Hedges' g = 0.28, 95% CI 0.08-0.49, p = 0.01; I² = 5.4%). However, in the absence of temporal profiling, this finding cannot be interpreted as evidence of circadian alignment.…
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