OBJECTIVES: The aim of this study was to describe the sleep patterns of intensive care unit (ICU) patients using portable polysomnography (PSG) and the Richards-Campbell Sleep Questionnaire (RCSQ), evaluate the correlation between these objective and subjective measures, and explore factors influencing sleep patterns in the ICU.
METHODS: This exploratory observational study was conducted as a substudy within the prospective SYNC (Sleep and circadian rhYthm in iNtensive Care unit) cohort study in a 42-bed surgical ICU of a university hospital. Patients with an anticipated ICU stay exceeding 12 h and requiring at least one overnight sleep were included. PSG was recorded during the first 3 ICU nights, and the RCSQ was administered on the following mornings.
RESULTS: We collected and analysed 110 valid PSG recordings from 56 patients, along with 145 valid RCSQ responses from 69 patients. Total sleep time (TST) ranged from 3.98 to 4.52 h per night. Patients had frequent nocturnal awakenings, ranging from an average of 12.84-15.48 times per night. Non-rapid eye movement stage 3 sleep was significantly reduced (1.50%-6.20%). Rapid eye movement (REM) sleep was nearly absent (0-0.9%). The TST and wake after sleep onset showed moderate correlations with RCSQ score (ρ = 0.599, p < 0.01, ρ = -0.586, p < 0.01). In time-adjusted univariable generalised estimating equation analyses, a longer TST was associated with younger age, higher Acute Physiology and Chronic Health Evaluation II scores, mechanical ventilation, receipt of sedatives/analgesics, physical restraints, and more frequent night-time nursing interruptions (all p < 0.05). REM sleep occurrence was more likely in younger and female patients and those with fewer comorbidities and less likely in patients with higher Acute Physiology and Chronic Health Evaluation II scores, mechanical ventilation, sedatives/analgesics use, physical restraints, and more frequent night-time nursing interruptions (all p < 0.05).
CONCLUSION: ICU patients had poor sleep quality during the initial ICU days, with insufficient TST, frequent awakenings, markedly reduced nonrapid eye movement stage 3 and near-absent REM sleep. Sleep disturbance was associated with both patient illness and medical treatments. Nurses should pay attention to patients' sleep time and quality and target modifiable factors, such as minimising nonurgent nighttime care during ICU stay.
REGISTRATION: The study protocol was registered on ClinicalTrials.gov (NCT06346613).
