CRITICAL CARE UNIT NOISE AND RAPID EYE-MOVEMENT (REM) SLEEP

Objective: To determine if Critical Care Unit (CCU) sound levels suppr ess rapid eye movement (REM) sleep. Design: Posttest-only control grou p experimental design. Setting: Sleep laboratory located in a universi ty neurologic institute. Subjects; Seventy paid ($40) women who had no hearing or sleep problems. Procedures: Subjects were randomly assigne d to a noise or quiet (control) group while attempting to sleep overni ght in the laboratory. Noise-condition subjects heard an audiotape rec ording of CCU nighttime sounds. The audiotape recording was withheld f rom the control group. Results: Subjects in the noise condition showed poorer REM sleep on seven of 10 Measures. These included REM activity and shorter REM durations throughout the night and during the first a nd second halves of the night as well as a longer interval between the first and second REM cycles. The majority of the t test results were significant at the 0.001 level or better. Conclusions: Although genera lization of the results to CCU patients is limited (because of the use of laboratory subjects), the results provided convincing support for a causal relationship between CCU sound levels and suppression of REM sleep.