Page 16 - Fall2019

Hospital Soundscapes
and Zhao (2012). Their aim was to determine which health- care facility design factors are most significant for clinical workers. They formed a list of 16 design factors that had been shown previously to be important to healthcare workers and administered a questionnaire to the medical staff. Analyzing their results using principal component analysis, they found three significant dimensions of importance in hospital designs: spatial, environmental, and maintenance. They found that cleanliness was the top concern of the staff, followed by air quality, then noise, and then thermal comfort.
More recently, an impressive body of work on hospital sound- scapes has been reported by Mackrill et al. (2013a,b, 2014), who studied a cardiothoracic ward. The aim of this study was to identify the positive and negative aspects of the hospital soundscape and to craft interventions based on the results.
The first part of the study used semistructured interviews with patients and staff to associate positive and negative words to sound sources. The next part of the study used recordings of the important noise sources in a laboratory lis- tening study. Subjects were asked to listen to each sound and describe how it made them feel. Semantic analysis was used to group results into positive, negative, or neutral emotions. Bipolar semantic scales were created from the expressions of subjects and then principal component analysis was used to determine significant dimensions. For instance, one scale went from calm to agitated and another from relaxed to stressed. This study found two significant perceptual dimen- sions: relaxation, which described 57% of the variance, and interest and understanding, which accounted for 13% of the variance. From this, the investigators concluded that patients and staff seek a relaxing soundscape and are more forgiving of noise if its purpose is understood.
The last part of the study by Mackrill and colleagues (2014) considered the potential to improve the soundscape by intro- ducing masking sounds. They found that added nature sounds improved the ratings of the soundscape by subjects along the relaxation dimension and that the improvement was greater than for traditional masking sounds. This result parallels Ulrich’s (1984) seminal work on the impact of views of nature on hospital patients and is aligned with a study by Annerstedt et al. (2013) that found that sounds of nature reduced cardio stress markers and cortisol levels after a stressing event.
Azzahra et al. (2017) asked nurses to rate the soundscape in an intensive care unit on a variety of preestablished bipolar scales such as pleasant to unpleasant. This work found three
significant dimensions: information, which accounted for 31% of the variance; calmness, which described 31% of the vari- ance; and dynamics (e.g., loudness), which accounted for 23% of the variance.
There is much work still to be done using soundscape analytical tools. For instance, noise interventions based on results have not yet been fully tested to confirm the techniques.
Interventions
Hospital soundscape interventions parallel typical noise con- trol approaches, which are normally classified as at the source, along the path, or at the receiver. Noise interventions are also conventionally described as physical, meaning there is a change in structure causing sound to be reduced, or adminis- trative, meaning that behaviors or processes change. In what follows, we highlight a few of the more unusual and interesting noise interventions in hospitals.
At the source, noise interventions are hard to find in hospi- tals. Medical equipment manufacturers are not focused on producing quieter machines, oral communication reigns supreme in medical facilities, and alarms continue to sound constantly. One administrative approach has, however, man- aged to improve the soundscape at least periodically, namely, the implementation of quiet times.
Quiet times are designated blocks of time (often two consecu- tive hours each day) during which hospital unit operations are intentionally minimized. Typically, lights are dimmed, doors are closed, and fewer procedures are scheduled. Both staff and patients appreciate these times of rest. Weber and Ryherd (2016) showed, for instance, that over 90% of nurses surveyed felt quiet times were useful to them, their patients, and the families of their patients. Similarly, Adatia et al. (2014) showed that quiet times were useful to new mothers.
Along the path, noise interventions usually consider the addi- tion of sound absorption or insertion of some sort of sound barrier. These are both problematic approaches in hospitals, where the ability to clean all materials regularly is important and where unit staff want to be able to see patients clearly to ensure safety and promote an efficient workflow. There are now a few lines of acoustical materials appropriate for use in hospi- tals, but the problem of direct sound paths remains.
An interesting approach to along the path noise interventions in hospitals was presented by Okcu et al. (2013), who studied
16 | Acoustics Today | Fall 2019