Content area
เอกสารฉบับเต็ม
BACKGROUND Sleep deprivation may contribute to impaired immune function, ventilatory compromise, disrupted thermoregulation, and delirium. Noise levels in intensive care units may be related to disturbed sleep patterns, but noise reduction has not been tested in this setting. OBJECTIVE To measure the effect of a noise reduction intervention on the sleep of healthy subjects exposed to simulated intensive care unit noise.
METHODS After digital audiotape recording of noise and development of the noise reduction intervention, 5 nocturnal 8-hour periods of sleep were measured in 6 paid, healthy volunteers at 7day intervals in a sleep disorders center. Polysomnographic data were collected by experienced sleep disorders technicians and scored by certified raters. After the first 3 quiet nights, earplugs were randomly assigned to be worn on the fourth and fifth nights during exposure to the recorded noise. Sound pressure levels were measured during all 5 nights.
RESULTS Sleep architecture and sound measurements on quiet nights did not differ significantly. Sound levels were significantly lower on quiet nights than on noise nights. Exposure to the noise increased the number of awakenings, percentage of stage 2 sleep, and rapid eye movement latency and decreased time asleep, sleep maintenance efficiency index, and percentage of rapid eye movement sleep. Earplugs worn during exposure to the noise produced a significant decrease in rapid eye movement latency and an increase in the percentage of rapid eye movement sleep.
CONCLUSION The results provide a reasonable basis for testing the effects of earplugs on the sleep of critically ill subjects. (American Journal of Critical Care. 1999;8:210-219)
Existing evidence suggests that sleep deprivation is a serious problem in the intensive care unit (ICU).1-10 Consequences of sleep deprivation may include impaired lymphocyte and granulocyte function,11 reduced number and activity of natural killer cells and lymphokine-activated killer cells,12,13 reduced inspiratory muscle endurance,14 decreased ventilatory ability and loss of pulmonary reserve in patients with obstructive lung disease,15 decreased ventilatory response to hypercapnia,16-18 disrupted thermoregulation,19 and sensory alterations (delirium).6,16-18,20
Empirical evidence suggests that exposure to simulated ICU noise in healthy subjects is causally related to reduced sleep efficiency, longer sleep latency, more time awake, suppressed rapid eye movement (REM) sleep, and increased arousals from sleep.10,21,22 Although the presence of excessive noise in the ICU has been amply...