Research shows that the sound and acoustics generated in healthcare settings have a major impact on both patients and nursing staff. Hospitals are now noisy places, and do not always provide an acoustic environment designed for healing. Sound levels are still increasing, but are we listening? Andrea Harman, Concept developer, Healthcare, Saint-Gobain Ecophon, discusses some of the main considerations in creating a quieter, more calming, recovery environment.
Poor room acoustic environments make us anxious, stressed, tired, and error-prone; thus when we imagine a space designed for rest and recovery, we think of a place that is quiet, peaceful, and calm – for both patients, and the people working there. In reality a hospital is very different to that image. Patients are often surrounded by noise from alarms, equipment, and voices, and since the 1970s sound levels have been increasing. While the World Health Organization (WHO) suggests that average hospital sound levels should not exceed 35 dB, many studies have shown levels that are consistently far higher than this.
A UK-based study on a stroke rehabilitation ward registered average daytime levels of 64 dB, and night-time levels of 56 dB, with repeated single sounds of 100 dB. Sound is expressed using a logarithmic scale, so the actual increase is far more impactful than the figures may suggest. 64 dB is the equivalent sound level to that of people laughing, while 100 dB is equivalent to someone close by using a jackhammer
Acoustic drawbacks of multi-bed wards
The design of spaces, and the materials used, will also affect sound levels, and how sound moves within the space. The open design and multi-bed wards of many hospital environments make them more accessible, and give staff a better overview, bringing them closer to patients. However, this often allows sound to travel long distances without interruption. The hard finishes designed for ease of cleaning and longevity reflect sound back into a space, so that it builds interference with communication, while also disturbing healing sleep, and increasing stress and anxiety. High noise levels from speaking and monitors and alarms close to patients are a constant problem, and our hearing is never turned off, with our brains constantly trying to process sound signals even when we are very ill or apparently unresponsive. Patients in Emergency Departments and intensive care units, and newborn babies in neonatal units, are especially sensitive to disturbing sounds.
Sleep disruption
We all know that it is often noise that prevents us going to sleep, especially when we are somewhere different, and that it is likely to be noise that wakes us up during the night. We also know how tired, sluggish, and stressed, we can then feel after a poor night’s sleep. For patients in hospital this stress has been negatively linked to delirium, pain perception, and wound healing.
Within intensive care patients can find some sound positive and reassuring, e.g. that of staff quietly checking on their wellbeing. However, hearing conversations between staff perceived to be about them or other patients, hearing other patients, but not being able to see them, and noisy monitors, can all have a negative impact. Average noise levels of up to 70 dB have been recorded inside incubators in neonatal units, with the noise of a porthole closing registered at 100 dB. High noise levels have been linked to an increased risk of premature babies developing permanent hearing damage.
There are also many examples of how the acoustic environment can positively affect patient outcomes. As noise at night stops us sleeping, it is an easy step to link a reduction in noise on a hospital ward to an improvement in sleep quality, and for this improved sleep to affect a patient’s mood, feelings, and outcomes
Swedish research study
In a research study at Huddinge University Hospital in Sweden, in an intensive coronary care unit, the room’s acoustic conditions were changed from soundreflective to sound-absorbent by installing a Class ‘A’ sound-absorbent suspended ceiling. This absorbed between 85 and 100% of the sound that reached it. Measurements and evaluations were taken both pre- and post- the ceiling change. The patients recovering with good room acoustic conditions required less pain medication, had a shorter hospital stay, and were far less likely to be readmitted to hospital within a three-month period following their initial stay. In addition, they recorded a more positive perception of their time in hospital.
Patients hopefully have a short hospital stay, but of course staff are exposed to this noise on a daily basis. Members of staff often rely on clear verbal communication in their work. A sub-optimal acoustic environment affects concentration, and increases the risk of miscommunication and errors, as well as contributing to unnecessarily high stress levels, irritation, tiredness, and fatigue. Long-term this has an impact on a person’s health and wellbeing. Furthermore, the Huddinge University Hospital research also showed that not only did patients perceive staff attitude as better during the period with good room acoustics, but the staff also felt better about their role.
Improving room acoustics in healthcare
There are many ways to improve acoustics in hospitals to help achieve a calmer, more restful, environment. Identifying the sources of noise and potential challenges is a good starting point:
Equipment noise
Equipment – ranging from food trolleys and bed mechanisms, to monitors and alarms – is one of the main sources of noise in hospitals and other healthcare facilities. Alarms are purposefully noisy – they are designed to jolt us into taking action, and are thus designed to activate areas of the brain that recognise danger. Elements to consider to help may include increasing the distance between noisy equipment and the patient, and whether procedures or timing of events could be changed to be less impactful on patients’ sleep. There are now alarms available that can be remotely monitored, or worn by medical staff, so that they alert the staff member, rather than adding stress to the patient. Some alarms can now be personalised to an individual’s baseline levels rather than an arbitrary one, and this has been shown to decrease the quantity of alarms that are activated. An option trialled in the US is for a ‘round’ that included an equipment check to decrease the number of alarms that go off due to malfunction, a need for battery replacement, or because medication has run out, thereby treating the potential cause before the alarm sounds, and helping to prevent ‘alarm fatigue’.
Voice noise
Overhearing conversations, and patients being in pain or delirious, are examples of vocal noise that can be discomfiting. This noise, alongside the sound of people snoring, is one of the less pleasant memories that many people are left with after being in hospital. Sometimes people are not aware of the sound environment or the impact of their contribution to it – especially visitors to a ward.
Signs are available that advise people that they are entering a quiet area to help encourage quieter behaviour. Visual monitors are also available with a ‘traffic light’ system that shows green when noise levels are within the desired range, amber when increasing, and red when too high. These levels are adjustable to suit the environment and needs of staff and patients. The use of suitable, movable sound-absorbent screens between patients could help limit noise travelling through a ward.
Room design and finishes
Our hearing has evolved so that it works best outdoors in the natural world. The objective of good room acoustic design in healthcare is thus to try to imitate nature’s acoustic environment inside hospitals. In the natural world we seldom find the straight, parallel, smooth, hard surfaces we find in hospitals. These reflect sound waves across a space, increasing reverberation, and producing disturbing responses. Long corridors designed only with sound-reflective surfaces will carry sound over longer distances.
From an acoustic perspective, irregular spatial design is preferable where possible. An area where this can be used is in Reception. Irregular or convex-shaped reception desks could help, as these distribute sound waves in different directions. If appropriate, soundabsorbent cleanable wall panels may be used to absorb noise around a nurses’ station, and within corridors, waiting areas, and consulting rooms, reducing the reverberation and overall noise level within the space. When printed, these also provide artwork, which can have a positive impact. However, generally it is the ceiling that is used to provide sound absorption, as it is a large, and often relatively uninterrupted, space. Many acoustically absorbent suspended ceiling systems are available that fulfill aesthetic, acoustic, and cleaning and infection control criteria, thus making them eminently suitable for use in healthcare.
A ‘cruel absence of care’
Florence Nightingale wrote in her notes on nursing in 1859 that ‘unnecessary noise is the most cruel absence of care which can be inflicted upon either the sick or well’. So today, over 160 years later, when noise is still a challenge, but solutions are available, we should be advocating good room acoustics in all healthcare spaces.
Andrea Harman
Andrea Harman is the Concept developer for Healthcare for the UK and Ireland for Saint-Gobain Ecophon. Having worked in room acoustics for over 25 years, she is active in developing the link between sound environments and wellbeing, and investigating how the acoustic feel of a space can affect performance, interaction, social inclusion, and patient recovery. Her aim is to use and share this information to help create better, less stressful, more ‘enabling’ spaces and experiences for everyone.