Sleep is a potent aid to healing. But hospital patients often have trouble falling and staying asleep. In a study conducted in a simulated intensive care unit, wearing eye masks and ear plugs helped subjects sleep better, suggesting that they'd do the same for actual hospital patients.

Particularly important was that nearly all subjects reported that the eye masks and ear plugs were easy to use.

Intensive care units are busy, noisy environments. Several studies in the last decade have shown that sleep disruption is common in ICU patients. Some studies have shown nighttime noise peaks of over 80 decibels in ICUs. And nighttime light interferes with the body's normal sleep cues. Ear plugs and eye masks are simple, inexpensive ways to reduce light and noise. This study tested their effectiveness and ease of use in a simulated ICU environment.

Subjects who wore the eye masks and earplugs had more REM (rapid eye movement) sleep, got to sleep quicker and had fewer sleep disruptions than the subjects who didn't wear the sleeping aids. Subjects who wore the sleep aids also reported better sleep quality in a sleep questionnaire. Particularly important was that nearly all subjects reported that the eye masks and ear plugs were easy to use.

Overall, the subjects preferred the eye masks to the ear plugs. Ten of the 14 subjects found the eye masks comfortable, while only six found the ear plugs comfortable. And while most patients found both aids effective and easy to use, more found this to be true of the eye masks.

Fourteen subjects spent four nights in a sleep center. The first night was to get them accustomed to sleeping in the center. The second night was the baseline night: quiet and dark. On the third and fourth nights, noise and light levels were changed to resemble typical ICU conditions. Half of the subjects wore eye masks and earplugs on night three; the other subjects wore them on night four.

Sound recordings were made of a typical ICU night shift and were played back in the sleep center to simulate the ICU noise level. Light level in the sleep center was kept at the average level recorded in the ICU (100 lux). Subject sleep was monitored for nine hours a night, from 10 pm to 7 am.

Sleep was monitored by attached electrodes, which recorded both the subjects' electroencephalograms and eye movements. Subjects also evaluated their sleep quality in a questionnaire.

One limitation of the study comes from its use of healthy subjects. Actual intensive care patients are severely ill and are experiencing many physical and psychological stresses that affect their quality and quantity of sleep. Nevertheless, the study does suggest that using earplugs and eye masks could be a simple and inexpensive way to improve the sleep of ICU and other hospital patients. The researchers hope that future studies will demonstrate whether their use will also lead to increased healing and improved hospital patient outcomes.

A provisional version of an article detailing the study results was published online April 15, 2010 by the journal Critical Care. This article is freely available.