Sleep in the ICU

Sleep is a complex process related to biologic and environmental factors essential to maintaining physiological and emotional well-being. Sleep disturbances and deprivation, and abnormal sleep architecture (prolonged sleep latency, sleep fragmentation, continuous arousals, a preponderance of inefficient sleep stages), frequently occur in critically ill patients, leading to adverse outcomes. Survivors of critical illness frequently refer to sleep deprivation as a major stressor associated with their admission. The following environmental (clinical and nonclinical) factors contribute to sleep disturbances in these patients: mechanical ventilation, drainage positioning and maintenance, bronchial aspiration, hygiene, nursing care, pain, light, and noise. Sleep duration in critically ill patients is shortened and fragmented, and sleep is essential for restoring energy and equilibrating the mind. Sleep deprivation hence alters cognition, leading to apathy, confusion, and delirium, all of which may increase morbidity and mortality. Sedatives are commonly given to critically ill patients to promote sleep, although physiological sleep and sedation may be significantly different. While patients may achieve an acceptable amount of sleep over a 24-h period, this sleep is both discontinuous and abnormally structured. Clinical guidelines strongly support and recommend the application of a multimodal approach aimed at promoting sleep that includes both environmental regulations and clinical assistance.