Sleep in Intensive Care Unit Patients

Abstract

Sleep disturbances are common among patients admitted to the intensive care unit (ICU); however, these issues tend to receive less attention because critical care is prioritized in seriously ill patients. Recent studies have reported that sleep disturbances in patients admitted to the ICU are associated with delirium, weakened immunity, long-term cognitive decline, and persistent sleep disorders. Sleep disturbances in the ICU are attributable to the disease per se and also to the ICU environment that is not conducive to good sleep. Continuous exposure to light and noise are major environmental risk factors that disrupt the circadian rhythm and interfere with deep sleep. Sleep analysis using polysomnography in patients admitted to the ICU typically reveals increase in sleep latency, sleep fragmentation, and decreased stage N3 and rapid eye movement sleep, which are associated with poor prognosis even in patients with severe neurological conditions, including traumatic brain injury and intracranial hemorrhage. Polysomnography is the gold standard for objective evaluation of sleep; however, its applicability is limited in ICU settings, and novel methods such as continuous electroencephalographic spectral analysis and actigraphy have recently been proposed in clinical practice. Efforts to reduce nighttime light and noise (which are modifiable environmental factors) can improve sleep quality. In this article, the author reviews the studies that discuss characteristics of sleep disturbances, the associated risk factors and their correlation with prognosis among patients admitted to the ICU, as well as possible strategies to improve sleep quality in this patient population.