Feasibility study of unattended polysomnography in medical intensive care unit patients

Abstract

Objectives: To evaluate the feasibility of using unattended, portable polysomnography (PSG) to measure sleep among patients in the medical intensive care unit (MICU).

Background: Accurate measurement of sleep is critical to studies of MICU sleep deprivation. Although PSG is the gold standard, there is limited data regarding the feasibility of utilizing unattended, portable PSG modalities in the MICU.

Methods: MICU based observational pilot study. We conducted unattended, 24-h PSG studies in 29 patients. Indicators of feasibility included attainment of electroencephalography data sufficient to determine sleep stage, sleep efficiency, and arousal indices.

Results: Electroencephalography data were not affected by electrical interference and were of interpretable quality in 27/29 (93%) of patients. Overnight sleep efficiency was 48% reflecting a mean overnight sleep duration of 3.7 h.

Conclusions: Unattended, portable PSG produces high quality sleep data in the MICU and can facilitate investigation of sleep deprivation among critically ill patients. Patient sleep was short and highly fragmented.

Keywords: Critical care; Feasibility study; Polysomnography; Sleep deprivation; Sleep fragmentation.

Figure 1

Patient enrollment, screening, and eligibility flow diagram. “×” with number indicates patients excluded from PSG sleep architecture analysis. HR indicates length of study in hours; PT indicates patient; PSG indicate polysomnogram.

Figure 2

Electroencephalography tracing from an atypical sleep patient. LOC and ROC indicate left and right electrooculogram respectively. C3, C4, F3, F4, O1, O2 indicate EEG lead locations. EMG indicates electromyogram and ECG indicates electrocardiogram.

Figure 3

Representative hypnograms between 10:00PM and 6:00AM reflecting patient sleep fragmentation in 5 typical sleep patients. R (bar above horizontal line) indicates REM sleep. W (gray line without bars above or below horizontal line) indicates wake state. 1, 2, and 3 (with bars of increasing depth below horizontal line) indicate stage N1, N2 and N3 sleep respectively.