Sleep deprivation in the critically ill

The sleep patterns of 9 critically ill subjects were studied in surgical and coronary intensive care units. Subjects had variable diagnoses and were studied for one night each, using EEG recordings. Visual, tactile, aural, emotional, somatic and cognitive stimuli perceivable by each subject were recorded. The mean sleep time for all subjects was 28.06 minutes (± 28.24 minutes). Two subjects achieved no sleep and 1 subject achieved 1 minute of sleep. The longest amount of sleep achieved was 73 nonconsecutive minutes. Stage I sleep was achieved for a mean of 22.78 minutes (± 26.09), and was the most commonly occurring stage of sleep. No REM sleep occurred. Fifty-eight different types of stimuli were recorded with a stimulus occurring an average of once every minute. The most frequently occurring group of stimuli was external to the subject's room, consisting primarily of nurse's voices and nonvoice noises at the nursing desk.