Hospital Noise Fractures Sleep, Slows Healing

Study showed that when sleep was disrupted, even for a few seconds, heart rates increased.

Nighttime noise in hospitals adds up to poor sleep, which may hurt healing when patients need it most, researchers found.

In a laboratory sleep study, recorded hospital sounds of overhead paging, IV alarms, squeaky carts, and the like disrupted sleep and raised heart rates, Orfeu M. Buxton, PhD, of Harvard and Brigham and Women’s Hospital in Boston, and colleagues reported.

Electronic alert sounds like ringing phones and IV alarms were the most “potent” in arousing sleepers, disrupting normal sleep brain wave patterns more than half of the time, even when set at their quietest settings.

Likewise, staff talking and voice paging at a level of 50 dB — quieter than normal conversation — disrupted sleep half of the time in the study, which appeared in the June 19 issue of the Annals of Internal Medicine.

“Preservation of patients’ sleep should be a priority for contributing to improved clinical outcomes for patients who are hospitalized,” Buxton’s group wrote.

Those benefits might include lower sedation requirements and shorter hospital stays, and even lower incidence of delirium in the intensive care unit, they suggested.

Many centers contacted by ABC News in collaboration with MedPage Today have started implementing various strategies to limit night noise, which is consistently a top complaint from inpatients.

That’s important to tackle not only for the sake of patients but also for the hospital’s reputation, Vineet Arora, MD, of the University of Chicago, commented in an email.

“Noise is a publicly reported quality measure for U.S. hospitals in CMS Hospital Compare [part of the HCAPS survey] and only half of patients report their rooms are kept quiet at night,” Arora wrote.

Common strategies cited were putting posters or stoplight-style monitors in hallways to remind staff and visitors to keep voices down, a switch to visual paging systems, and setting up “quiet time” hours.

The study included 12 healthy adults who slept in a sound-dampened sleep lab for polysomnography over three nights.

After a run-in night, participants were exposed to 14 common sounds — such as voices, IV alarm, phone, ice machine, toilet flush, laundry cart, outside traffic, and helicopter noise — played at levels increasing from 40 to 70 dB during specific sleep stages to test the impact.

Sleep was easier to disrupt in the phase after the transition into sleep, called N2, that adults spend most of their time asleep in, compared with the next deeper, slow-wave sleep phase called N3 or the rapid eye movement phase.

Overall, as expected, louder sounds were more likely to disturb brain wave patterns during sleep.

Arousal occurred at lower sound levels on the third night than on the second night, suggesting some sensitization to nighttime noise in the hospital.

Heart rate jumped about 10 bpm when a sound fully roused a sleeper.

These results likely underestimated the impact of noise on sleep among inpatients due to the young population studied, whereas the typical hospitalized patient is older with medical and psychiatric conditions, as well as pain and medication use, all of which contribute to a harder time reaching the deep N3 stage of sleep, Buxton’s group cautioned.

Another limitation in that regard was that noise exposure was sequential, kept to 10 seconds or less, and halted if a participant started to wake up, which is not the case in a real hospital setting, the investigators added.

By Crystal Phend