Architecture and evolution of sleep during adult intensive care unit stay: A scoping review

Sleep is essential for maintaining health, yet patients hospitalized in intensive care units (ICUs) face an environment highly unconducive to quality sleep due to multiple disruptive factors. Understanding sleep architecture in the ICU is essential for comprehensive patient care.

This scoping review aims to synthesize current knowledge on sleep architecture in adult ICU settings while identifying knowledge gaps and proposing areas for future research.

A systematic search was conducted across PubMed/MEDLINE and Cochrane Library databases from 1987 to 2024 using specific keywords to identify publications on sleep in adult ICU patients that included electroencephalographic (EEG) data. The search was supplemented by reviewing bibliographies of included articles and conducting a complementary Google Scholar search. Data extraction followed PRISMA-ScR guidelines.

Of 961 studies identified from databases and 709 from other sources, 150 publications were included comprising 69 reviews, 55 observational studies, and 24 randomized trials. The majority were single-center studies (87.6%) with small sample sizes (58% with n < 25). Measurement methodologies were highly heterogeneous regarding recording duration (2-57 h), timing during ICU stay, patient populations (ventilated vs. non-ventilated, medical vs. surgical), and scoring methods. Only 3 studies (3%) examined sleep longitudinally. Among 74 observational studies and trials from the 2000s onwards, only 21 (26%) considered atypical sleep in their scoring methodology.

Current knowledge of ICU sleep is based predominantly on single time-point assessments with significant methodological heterogeneity. The critical gap is understanding sleep evolution over time. Simplified, validated monitoring tools are needed to enable prolonged sleep assessment in critically ill patients and inform evidence-based interventions.