By Sean Browne
Hospitals are inherently noisy for two primary reasons. First, there is the abundance of noise sources, from paging systems and patient monitoring equipment to staff conversations and the bustle of visitors. Second, walls, floors, and drywall ceilings tend to be hard surfaces, designed for durability and cleanliness, but this also creates excessive reverberation in a space. Consequently, they reflect rather than absorb sound, making already noisy spaces noisier. High noise levels in hospitals have implications for the health and well-being of both patients and staff.
The World Health Organization (WHO) guidelines for maximum noise levels in patient rooms are 35 dBA (decibels, A-weighted) during the day and 30 dBA at night. However, when researchers examined the hospital noise levels as reported in a myriad of studies, not a single hospital reported noise levels in compliance with the WHO guidelines. (Visit apps.who.int/iris/handle/10665/66217 to read “Guidelines for Community Noise: In Protection of the Human Environment” by B. Bergland, T. Lindvall, D.H. Schwelaand, and T.K. Goh, published by World Health Organization in 1999.)
Studies validate noise problem
A series of research studies at Johns Hopkins Hospital in Baltimore validates the problem of noise in hospitals. The first investigated noise levels in the facility’s emergency department (ED) where there is a constant flow of patients, doctors, nurses, and moving equipment. (For more information, read “Noise in the Adult Emergency Department of Johns Hopkins Hospital” by D. Orellana, I.J. Busch-Vishniac, and J.E. West, in the April 2007 edition of The Journal of the Acoustical Society of America.)
Researchers found high sound levels day and night, particularly in the speech frequency band, caused by the need to communicate constantly for performing necessary functions. Compared to patient rooms, the ED tends to exhibit sound levels nearly twice as loud. WHO recommends noise levels must be kept as low as possible in intensive care units and operating areas.
Researchers also noted it is likely staff members raise their voices above the background noise level in order to be understood. Medical staff fatigue then becomes a potential issue since speaking in a raised voice is tiring.
A universal problem
Another Johns Hopkins study, much broader in nature in that it looked at noise levels throughout the hospital, observed sound levels significantly exceeded WHO guidelines. (Visit asa.scitation.org/doi/10.1121/1.2118327 to access “Noise Levels in Johns Hopkins Hospital” by I. Busch-Vishniac, J. West, C. Barnhill, T. Hunter, D. Orellana, and R. Chivukula and published in December 2005 issue of The Journal of the Acoustical Society of America.) Moreover, all the measured average sound levels exceeded the typical speech level for communication between two people, once again suggesting staff routinely need to raise their voice to be heard.
According to researchers, the study results not only demonstrate a noise problem in Johns Hopkins Hospital, but also suggest the problem of hospital noise is universal, and noise control techniques would be valuable if applied broadly.
In its conclusion, the study states:
It is important to not only characterize the existing environment, but to understand why it is so noisy. To this end, we note hospitals are notoriously lacking in the materials one normally associates with acoustical absorption. This is largely the result of concerns about infection control, wear, and cost. However, there are materials available that meet hospital standards in these areas as well as in related areas such as flammability and smoke production.