Nearly 1 million patients develop respiratory failure annually in the United States; yet, the sleep of patients undergoing mechanical ventilation has received little attention. This project is designed to characterize sleep and circadian rhythmicity in critically ill patients and to explore the efficacy of a non-pharmacological intervention to improve sleep and normalize circadian phase. The study will examine the effect of a protocol employing noise reduction and enforcement of a robust light-dark cycle on sleep quality and circadian rhythmicity. A secondary analysis will examine the relationship between delirium and sleep disruption and loss of circadian rhythmicity. Circadian rhythmicity will be characterized through the measurement of urinary 6-sulfatoxymelatonin levels at frequent intervals, while sleep will be assessed using continuous polysomnography.
