154th ASA Meeting, New Orleans, LA

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Toward a less chaotic sound environment for nurses:

A study investigating the relationship between layout design, aural connectivity and user activities

Selen Okcu
GaTech College of Architecture, Atlanta, GA, 30332

Craig Zimring
GaTech College of Architecture, Atlanta, GA, 30332

3aNS7. Soundscape Developments: Case Studies and Best Practices

Session: Thursday Morning, Nov 29

154th Meeting of the Acoustical Society of America, New Orleans, Louisiana. 

Most hospitals routinely exceed the World Health Organization guidelines (35 Db at night and 45 Db during the day), and the Mayo Clinic sleep team recently recoded peak noise at the head of patient beds of 113 Db—louder than a jackhammer. These harsh and cacophonous settings fall far from supporting the mission of hospitals: to allow patients to heal and staff to do precise work that has life-and-death implications. Noise interrupts sleep, causes stress, and contributes to medical errors. Intensive care units—the focus of this study—are particularly noisy, with hundreds of alarms, noisy ventilators and other sources of noise.

While the measures to limit excessive noise are becoming understood—reducing  noise sources from alarms and paging, enclosing generators of noise and creating much better physical designs that reduce sound reflection and transmission, etc.—it is much less clear what sound environment clinicians need to do their jobs. Healing and work requires a complex choreography of sound isolation and transmission that is only beginning to be understood. On one hand a patient should be able to sleep peacefully while the patient next door is undergoing care, yet a patient or family member should be able to summon help rapidly when needed, and a clinician should be able to monitor subtle breath sounds or other clinical indicators. While some of this can be provided electronically, it is becoming clear that the lessons of the concert hall or workplace also apply to the hospital: appropriate physical design, augmented by electronics, is needed to support the tasks and needs of the people using it. 

These questions are taking on special urgency as the US enters one of the largest building booms in its history. The construction tracking firm FMI predicts that healthcare construction will exceed $60B a year by the end of the decade, and will continue to grow for the foreseeable future. At the same time, hospital designers and clients are becoming aware that physical design can impact healthcare safety, quality and efficiency. Many hospitals are adopting “evidence-based design” where designers and clients explicitly use research to make design decisions. For example, the US Assistant Secretary of Defense recently directed that evidence-based design be used in all 70 military hospital and 800 clinics world-wide, including the $6B replacement of Washington’s Walter Reed Hospital. Hospital designers are looking for valid, usable research to implement.

This study explores what key sounds nurses need to hear and understand to do their job effectively. It particularly focuses on sounds impacted by the design of the physical environment. While alarms and electronic monitoring play a key role, nurses rely on ambient sounds to do their jobs as they move through the intensive care unit. Non-alarm sounds allow nurses to monitor the real-time sound events in the unit, such as changing tone of the patients` breathing, varying patterns of coughing, a fall, or a cry for help. Audibility level of these key non-alarm sounds is critical in the intensive care settings because ability to listen to these sounds can provide further audio clues to caregivers about the patients` health condition that cannot be always captured by preset medical equipment.

This study explores the sound environment in an innovative neuro intensive care unit that was designed with explicit goals of reducing noise. It describes the existing sound environment and identifies the range of tasks that ICU nurses do and how sounds help and hinder them doing those tasks. The study begins to develop a method called aural connectivity that will allow acousticians, architects and others to map where clinicians should be able to hear key sounds and provides the basis of field studies to compare actual with predicted performance. It will allow designers to help tune the layout, materials and design of an intensive care unit to help actually achieve its intention: healing and error-free work.

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