PROVIDENCE, R.I.--There is no rest for weary hospital patients.
A new study shows a very strong relationship between the number of loud sounds--80 decibels or greater--and sleep arousals among elderly patients in a hospital's intermediate respiratory care unit. A loud beeper could produce an 80-decibel sound.
"During an eight-hour period, from 10 p.m. to 6 a.m., we found that loud noises markedly disrupted the sleep of patients," said Richard Millman, M.D., one of the study's authors. Millman is professor of medicine at Brown University and director of the Sleep Disorders Clinic at Rhode Island Hospital. "The patients spent a huge percentage of the time awake during the night."
The authors suggest that hospitals modify the sounds produced in the critical care setting and find ways to screen patients from noise pollution. The sounds came from various sources, such as loud voices, televisions, equipment alarms, intercoms and beepers.
For the study, medical personnel at Brown University monitored overnight the link between peak sound levels and arousals from deep sleep in six elderly patients. They found a very strong correlation between the number of sound peaks and sleep arousals. For example, not counting interruptions by nurses or doctors, the researchers found 29 peak sound levels were associated with 28 sleep arousals in one patient during a one-hour period. In another patient, 34 sound peaks were correlated with 42 arousals in one hour.
Medical personnel aren't sure how disrupted sleep affects elderly patients. Some studies show that at least one-third of sleep-deprived hospital patients have what is called "ICU psychosis," marked by symptoms of nighttime disorientation and delusion. Sleep deprivation may also adversely affect respiratory muscle function, possibly hindering weaning from mechanical ventilators, Millman said.