Sleep, circadian rhythms and outcomes in intensive care unit.
Level 5 - mechanism / opinion, no new human data
Narrative review without systematic search or meta-analysis
PubMed 42293078 · doi:10.3389/fneur.2026.1790266
What was done
This narrative review summarizes literature on sleep architecture and circadian rhythm disruptions in adult intensive care unit (ICU) patients. It reviews assessment tools—including polysomnography, electroencephalography (EEG), actigraphy, cardiopulmonary coupling, hormonal profiling (melatonin, cortisol), core temperature rhythms, and clock gene expression—and synthesizes their associations with acute ICU outcomes and post-discharge recovery.
What was found
The abstract reports qualitative narrative associations and provides no quantitative data or effect estimates. Sleep architecture disruptions (decreased total sleep time, loss of REM sleep, atypical EEG patterns) were associated with prolonged mechanical ventilation, weaning failure, noninvasive ventilation failure, and delirium. Circadian disruptions (blunted or phase-shifted hormonal rhythms, altered clock gene expression) correlated with systemic inflammation, disease severity, and mortality. Persistent disturbances post-discharge were associated with cognitive impairment, psychological distress, fatigue, and lower quality of life.
Why it matters
This paper consolidates evidence positioning sleep and circadian rhythms as clinically meaningful biomarkers of ICU severity and acute brain dysfunction, identifying them as potential targets for interventional trials.
Limits
As a narrative review, it lacks systematic search criteria, quality appraisal, and meta-analytic pooling. The abstract reports no numerical findings. The underlying literature is predominantly observational and subject to heavy confounding by sedation, critical illness severity, and ICU environmental factors, precluding causal conclusions.
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- context ICU psychosis is a clinical phenomenon in intensive care units driven by severe circadian rhythm disruption and fragmented sleep, which typically resolves once the patient goes home.