Effects of critical care unit noise on the subjective quality of sleep

Nurse researchers have provided evidence that hospital critical care unit (CCU) noise may put patients at risk for sleep problems. Technological advances in this setting have been described as contributing to this problem. Although data on the negative effects of CCU noise on physiological sleep are available, less attention has been given to self-reports of the subjective quality of sleep following exposure to this stressor. This study hypothesized that subjects exposed to CCU sound levels would report poorer subjective sleep than subjects in a quieter environment. Sixty female subjects, attempting to sleep overnight in a laboratory, were randomly assigned to an experimental group, where they heard an audiotape recording of CCU sounds throughout the night, or to a quiet group where the audiotape recording of CCU sounds was withheld. A self-rating questionnaire was used to assess subjective sleep. The noise condition subjects reported taking longer to fall asleep, less time sleeping, more awakenings, poorer quality of sleep compared to home, as well as fewer positive and more negative adjectives descriptive of sleep. Self-reports of the time spent sleeping and the number of negative adjectives descriptive of sleep yielded the greatest number of significant correlations with scores for the other measures of sleep, indicating that these measures may be more accurate. Data on the quality of dreams yielded no difference between groups. The results provide support for the hypothesis that CCU sound levels impact negatively on subjective sleep. It was recommended, now that CCU sound levels were isolated in the laboratory as a potential stressor, that future research should attempt to replicate this study in a hospital CCU.