“Unnecessary noise is the most cruel absence of care which can be inflicted either on sick or well.” – Florence Nightingale, 1859
The hospital soundscape easily becomes a cacophony: screeching curtain rails, the ward phone wailing like an infant, the endless hum of conversations we choose to tune into intermingled with those we wish we could ignore. The ideal sense of quietness on a hospital ward is the absence of annoying noise rather than the absence of sound itself.
Healthcare workers constantly find themselves struggling to sift through a haphazard auditory environment hoping to identify vital clinical information. Excessive and non-intuitive sounds have a critical effect on sleep disturbance for patients and communication interference for staff. Sound can act as an ‘ambient stressor’, leading to subjective and physiological stress, alarm fatigue, and wears down the locus of control healthcare staff have over their environment [1]. Doctors often prefer to work in a quieter, off-ward office space for this reason. The reduced presence of doctors on-ward can cause friction with other healthcare workers and create risks with emergency alarms being missed or misattributed.
Statistics around hospital soundscapes are particularly alarming (pardon the pun here): hospital wards tend to average 60 to 70 dB, somewhere halfway between a vacuum cleaner and a disposal lorry, with peaks of 90 dB, equivalent to a busy motorway [2]. ICU psychosis is often characterised by traumatic memories of the auditory environment, and delirium affects up to 80% of ICU inpatients, many of whom require extensive psychological support [3]. The FDA Manufacturer and User Facility Device Experience (MAUDE) database has recorded over 600 adverse events including deaths linked to alarm mismanagement [4].
The consequences of sleep deprivation on healing times and llength of hospital stay is well established [5]. Uninterrupted sleep also allows for the processing of stressful memories, peaking at the 7 – 8 hour mark during intense REM cycles [6]. White noise trialled in ICU environments approximately halved the number of sleep arousals by closing the gap between environment sound peaks and baseline noise levels [7]. Alarm systems themselves can also be modified to compute a frequency which allows the alarm noise to be audibly different to surrounding hospital noise [8]. Recent standards for manufacturers aim to unify the design of auditory tones and eliminate alarm ambiguity and reduce hospital noise in the process [9]. However unification of alarm sounds by modern standards has resulted in ‘alarm masking’ whereby multiple alarm sounds become indistinguishable from one another [10]. There still also remains the issue of the sound of alarms having no association with their underlying meaning [11].
Simple interventions in hospital design can have significant impact on patient outcomes. For instance, patients with views of trees have consistently shorter hospital stays, lower analgesic requirement and a more positive subjective hospital experience compared to those with views of brick walls [12]. Playing music to patients was the only successful environmental intervention to reduce pre-procedural, procedural and post-operative anxiety in a Cochrane review, in part through the reduction of unpleasant ambient noise [13]. The addition of natural sounds such as birdsong and water alongside written information for patients to understand and become more comfortable with sounds on a hospital ward resulted in improved emotional-cognitive scoring in relation to relaxation, interest and understanding [14]. Another simple soundscape intervention is the Canary Box, a technology employed in surgical theatres which adjusts the volume of music being played in accordance to anaesthetic observations, avoiding the possibility of loud music interfering with communication and focus during an intraoperative deterioration [15]. An exciting technology targeted at non-verbal patients and those whose communicative methods fall outside normal social expectations is biomusic, which translates meaningful changes in autonomic features (heart rate, skin temperature, sweating by electrodermal activity) into melodic sound. Through physiological signs, clinicians and carers may be better able to distinguish affective states such as anxiety within healthcare settings [16].
These soundscape innovations are hopefully just the start. Clinicians deserve a future in which alarms are intuitive and evoke trends in patient observations. Alarm signals should not be so strong that they cause fatigue or habituation amongst medical staff and interrupt workflow. Imagine if the hospital soundscape was less like a cacophony and more like an orchestra: full of meaningful, intentional information which give patients peace of mind and allow clinicians to make better decisions.
References
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[2] Mackrill J, Jennings P, Cain R. Exploring positive hospital ward soundscape interventions. Applied ergonomics. 2014 Nov 1;45(6):1454-60.
[3] Ouimet S, Kavanagh BP, Gottfried SB, Skrobik Y. Incidence, risk factors and consequences of ICU delirium. Intensive care medicine. 2007 Jan;33:66-73.
[4] Food and Drug Administration. Manufacturer and User Device Experience (MAUDE) Database: Alarm Related Death Events
[5] Pilkington S. Causes and consequences of sleep deprivation in hospitalised patients. Nursing Standard. 2013 Aug 7;27(49).
[6] Boyce R, Williams S, Adamantidis A. REM sleep and memory. Current Opinion in Neurobiology. 2017 Jun 1;44:167-77.
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[8] Hasanain B, Boyd AD, Edworthy J, Bolton ML. A formal approach to discovering simultaneous additive masking between auditory medical alarms. Applied ergonomics. 2017 Jan 1;58:500-14.
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[10] Bolton ML, Zheng X, Li M, Edworthy JR, Boyd AD. An experimental validation of masking in IEC 60601-1-8: 2006-compliant alarm sounds. Human factors. 2020 Sep;62(6):954-72.
[11] Edworthy J, Reid S, McDougall S, Edworthy J, Hall S, Bennett D, Khan J, Pye E. The recognizability and localizability of auditory alarms: Setting global medical device standards. Human factors. 2017 Nov;59(7):1108-27.
[12] Ulrich RS. View through a window may influence recovery from surgery. science. 1984 Apr 27;224(4647):420-1.
[13] Drahota A, Ward D, Mackenzie H, Stores R, Higgins B, Gal D, Dean TP. Sensory environment on health‐related outcomes of hospital patients. Cochrane Database of Systematic Reviews. 2012(3).
[14] Mackrill J, Jennings P, Cain R. Exploring positive hospital ward soundscape interventions. Applied ergonomics. 2014 Nov 1;45(6):1454-60.
[15] Hocevar R. Overriding the ‘Culture of Music’in the OR. ASA Monitor. 2024 Mar 1;88(3):34-.
[16] Blain-Moraes S, Chesser S, Kingsnorth S, McKeever P, Biddiss E. Biomusic: A novel technology for revealing the personhood of people with profound multiple disabilities. Augmentative and Alternative Communication. 2013 Jun 1;29(2):159-73.
