Noise is a significant issue for many hospitals. In fact, MacKenzie and Galbrun found that there are typically no less than 86 different sources, including patients, staff and visitors talking, as well as the cacophony produced by televisions, alarms, carts, doors, medical equipment and mechanical systems. 1
These sounds cause more than just irritation. A growing body of research shows that noise can actually harm patients by, for example, elevating heart rate and blood pressure. 2 Furthermore, noise prevents patients from getting the rest they need, weakening the immune system and leading to problems during the day such as agitation, delirium and decreased tolerance to pain. 3
However, patients are not the only ones affected. Though one might think that staff can become hardened to noise over time, no one is able to fully tune these disturbances out because our senses are designed to detect such changes in our environment. Noise disruptions impact caregivers’ concentration, causing stress and fatigue, and potentially affecting quality of care. 2
The financial impact of this problem can also be substantial, particularly given the connection between Hospital Consumer Assessment of Healthcare Providers and Systems (HCAHPS) scores and government funding. HCAHPS surveys are the basis for calculating Patient Satisfaction Scores under the Value-Based Purchasing (VBP) program, which penalizes poorly performing hospitals by withholding Medicare payments. To date, noise remains the lowest-rated marker of patient satisfaction across the United States.
Speech privacy is yet another acoustical concern in healthcare settings. Patients know that it if they can overhear conversations occurring in neighboring areas, others can hear them as well, making them uncomfortable and less likely to discuss private matters with their caregiver. Their right to oral privacy has also been officially recognized in the Health Insurance Portability and Accountability Act (HIPAA), which requires all healthcare entities to take ‘reasonable safeguards’ to protect in-person and telephone communications.
Hospitals will benefit from applying the prescription acoustic professionals use to address noise and speech privacy. This three-pronged approach, which involves absorbing, blocking and covering, is commonly referred to as the ‘ABC Rule.’
‘A’ stands for adding ‘absorption.’ Hospitals often feature hard finishes that cause noises to echo, overlap, linger and travel great distances. Adding absorptive materials that still meet the criteria for sterility and washability will reduce the energy and, therefore, the volume of noises reflected off their surfaces back into the space.
The ceiling is often the most significant source of absorption. In fact, a Swedish study determined that cardiac patients in rooms with absorptive ceiling tiles were less likely to be readmitted than those in traditional rooms. 4 Select a tile with a high Noise Reduction Coefficient (NRC) rating and ensure consistent coverage throughout the building.
Hanging absorptive wall panels may also be needed in some situations. They are most effective when applied to large vertical surfaces and key reflective locations, such as corridors. Soft flooring can be used to lessen footfall and other 'traffic' noise.
‘B’ is for ‘blocking’ noise using physical barriers and a well-planned layout.
The most basic barrier is a wall, such as those around private patient rooms. However, a well-planned layout can also be used to minimize direct (i.e. line of sight) noise transmission. For example, high activity areas and machines such as icemakers should be located in areas that are well-separated from patient rooms. Doors facing each other across hallways should be offset.
It is also helpful to rethink traditional aspects of the hospital landscape. For instance, nursing stations can be decentralized in order to prevent large groups from talking near patients’ rooms. 4 Some hospitals are even re-evaluating their open door policy in an attempt to block noise. Of course, caution needs to be taken when applying blocking tactics in hospitals, because caregivers need to be able to readily monitor and access patients.
HVAC components and any gaps, such as those under doors, must be properly treated to prevent them from providing paths for noise.
Most people believe that ‘silence is golden’ and try to use absorptive materials and blocking strategies to achieve the lowest possible volumes. However, noise control and speech privacy remain elusive goals.
The fact is that it is impossible to eliminate all noise from a busy, 24-hour healthcare environment. Furthermore, the more silent one makes a space, the louder any remaining noises seem to occupants. This phenomenon can be attributed to the fact that an effective acoustic environment relies in part on the provision of an appropriate noise floor or level of continuous background sound. If this level is not high enough, occupants can clearly hear conversations and noises, even if they are relatively low in volume or generated at a distance.
That is why resources such as the FGI/ASHE Guidelines for the Design and Construction of Health Care Facilities now recommend the use of sound masking systems in healthcare applications.
This technology consists of a series of loudspeakers, which are usually installed in a grid-like pattern in or above the ceiling. The loudspeakers distribute a comfortable, engineered sound that most people compare to softly blowing air. Although masking increases the background sound level, occupants perceive treated spaces as quieter because it covers up noises that are lower in volume and diminishes the impact of those that are higher by reducing the magnitude of change between baseline and peak levels. For this reason, sound masking has also been found to be a very effective method of improving sleep. 3 In fact, in a study of ICU patients, quality of sleep improved by 42.7 percent when sound masking was used. 5
Masking requires some distance to become effective, so it does not prevent patients and staff from communicating with one another. However, it is nonetheless important to look for a sound masking system that can provide local control for individual rooms or areas, allowing occupants or staff to adjust the volume as needs require. In this case, the masking will not only improve comfort, but also increase patients’ sense of control over their environment.
One tactic overlooked by the ‘ABC Rule’ is the identification and subsequent reduction or elimination of unnecessary sources of noise. Suggestions for hospitals include:
• Purchasing quiet hand towel dispensers and door hardware, as well as rubber-wheeled carts
• Limiting or eliminating the use of overhead paging
• Turning off unwatched television sets and/or requesting that patients use headphones
• Responding to alarms promptly
• Providing training on how to handle loud vocalization by patients
This strategy also involves raising caregivers’ awareness of their own actions, such as talking loudly or yelling down the hallway at each other. Some hospitals have asked staff members to form a special committee to develop and enforce policies aimed at controlling noise. Visitors should also be educated about the negative effects of noise and encouraged to follow the rules.
However, people will always create noise as they converse and perform tasks. After best efforts have been made to reduce noise at its source, all the noises that remain are there by necessity or because they are impossible to eliminate. These noises, and speech privacy concerns, must be addressed through absorption, blocking and covering up. These design strategies are very effective and do not add to the burden of caregivers, who are already stretched thin.
Niklas Moeller is vice-president of K.R. Moeller Associates Ltd., a global developer and manufacturer of sound masking system, LogiSon Acoustic Network. He also writes a weekly acoustics blog called “UnMasked – an inside look at acoustics.”
1. MacKenzie DJ and Galbrun L: Noise levels and noise sources in acute care hospital wards. Building Services Engineering Research and Technology, 2007 Vol. 28, No. 2, 117-131.
2. Joseph A and Ulrich R: Sound Control for improved outcomes in healthcare settings. The Center for Health Design, 2007.
3. Xie H, Kang J and Mills GH: Clinical Review: The impact of noise on patients’ sleep and noise reduction strategies in intensive care. Critical Care 2009, 13:208 doi: 10.1186/cc7154.
4. Bennett D: Fixing the noisy hospital: The clamour of modern medicine can actually make us worse. So how do you write a prescription for shhh? The Boston Globe, May 30, 2010.
5. Stanchina ML, Abu-Hijleh M and Chaudhry BK: The influence of white noise on sleep in subjects exposed to ICU noise. Sleep Med 2005, 6:423-428.