ASA Lay Language Papers
161st Acoustical Society of America Meeting

Effects of noise on emergency department staff

Arun Mahapatra –
Erica Ryherd –
Woodruff School of Mechanical Engineering
Georgia Institute of Technology
Atlanta, GA 30332

Selen Okcu –
Craig Zimring –
College of Architecture
Georgia Institute of Technology
Atlanta, GA 30332

Jeremy Ackerman –
Dept. of Emergency Medicine
Emory University School of Medicine
Atlanta, GA 30322

Popular version of paper 5aAA5
Presented Friday morning, May 27, 2011
161st ASA Meeting, Seattle, Wash.

Working in an emergency department (ED) is often chaotic and stressful, with medical alarms, equipment sounds, and numerous conversations part of the typical soundscape.  These sources, combined with hard surfaces, combine to form a complex acoustic environment that may decrease the quality of speech communication and increase mental fatigue in hospital staff.  While some research has been done to document the overall loudness levels of noise in EDs, little data exists about other important acoustic qualities (such as fluctuations in noise over time and measures reflecting effects on speech) that fully describe the sound environment of an ED and how they are related to the hospital staff.

Researchers from the Healthcare Acoustics Research Team (HART) investigated the EDs of two hospitals for overall noise levels, the Speech Intelligibility Index (also known as the SII, the ability of a listener to understand speech), and other measures in order to more accurately describe the acoustic environment and to assess its impact on staff.  Measurements were taken over a twenty-four hour period in the main work areas for physicians and nurses, as well as patient rooms.  In each hospital, there are two major areas in each ED - the main urgent care area (Main ED) and the Critical Decision Unit (CDU) – resulting in a total of eight measurement locations.  The Main ED handles a majority of patients while the CDU is a smaller area designed for twenty-four hour testing, monitoring and treatment.

The overall loudness of the background noise in both hospitals was found to be very similar.  The main work areas exhibited a background noise level between 59 – 63 dBA (A-weighted decibels).  The levels found in patient rooms were more varied, ranging between 50 – 63 dBA.  To put this in context, the World Health Organization (WHO) suggests that background noise levels in patient rooms stay below 30 dBA and that exceeding this level can cause significant sleep disturbance. 
In part because of these elevated noise levels, the speech intelligibility indices (SII) of the various ED spaces were measured to be very low.  In six of the eight locations studied, the SII value was less than 0.45 – a level that corresponds to “poor” speech intelligibility in the American National Standards Institute (ANSI) system.  The remaining two locations maintained a higher SII level, but not high enough to be considered spaces with “good” intelligibility according to ANSI.  This finding is particularly significant due to the dependence of healthcare delivery on oral communication.

The question remains: how do these troubling findings affect the hospital staff? The staff working in the two EDs measured in this study were surveyed to measure their perception of different elements of their work environment.  The surveys assessed such elements as overall stress levels, how satisfied staff members are with their jobs, and their commitment to their organization as a whole. The research team is still analyzing these results. This initial data will allow future experiments to more clearly determine the effects of the soundscape on staff members.

To summarize, this study further extends our knowledge of the acoustic environment of the soundscape in a complex clinical environment. The poor SII found throughout these two emergency departments is concerning as it may affect communication between clinical staff members and between staff and patients. The team has begun exploring how the soundscape effects staff members as they are delivering medical care. Ultimately, the results from this study will allow for a greater understanding of the inner workings of an emergency department – specifically, how the acoustic environment affects hospital staff as they operate in chaotic situations.  As more knowledge is gained on this matter, it will allow the opportunity to maximize the quality of healthcare in the future.

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World Health Organization. "Guidelines for Community Noise." Geneva, 1999.

ANSI. "Methods for Calculation of the Speech Intelligibility Index." American National Standards Institute, 1997: S3.5.

Leather, Phil, Diane Beale, and Lucy Sullivan. "Noise, psychosocial stress and their interaction in the workplace." Environmental Psychology, 2003: 213-222.