HOSPITAL NOISE

Noise is annoying.

Not only does it have a cardiovascular and physiological effect, it also effects mental health.

The World Health Organisation has a recommended sound level for hospital patient rooms as 35 dBA. 

An example of that measure is a very quiet room fan at a low speed at a distance up to a metre.

The noise of normal living or talking is 45 dBA.

 A noise level of 40 dBA may cause interruption in activities that need concentration.

Hospitals are noisy.

And intensive care units (ICU) are the noisiest part of a hospital.

During the day, the noise levels in ICU regularly reach just under 60 dBA with peaks of above 100 dBA.  

You will have experienced a 60 dBA level in a busy restaurant.  

A two stroke chainsaw at 10 metres records a reading of 85 dBA.  

This is the peak sounds that occur nightly in ICU’s up to 16 times an hour.  

The sickest patients in a hospital are subjected to regular noise levels that people would find intolerable.  

In a list of top ten disruptive noises on a ward form an inpatient survey, the number one disruptive noise was patient buzzers.  

Followed by patient infusion alarms, staff talking and laughing, ward phones ringing and wheels from trolleys or commodes.  

Other patients snoring came in a number six, lights being kept on late or all night (not noise but disturbing) at seven, staff banging doors, drawers or bin lids at eight, confused or agitated patients at nine and the footsteps or footwear of staff at ten.  

All of these disruptions are, to some extent, preventable or can be ameliorated by staff.  

They require an awareness of staff that the environment that they are creating is not peaceful.  

As hospital stays are shorter, patients should be able to recuperate the best they can before they are discharged.  

If the level of noise is like being in a noisy cafe all the time, patients will not recover as quickly as they should.

Alarms are is used in the absence of adequate staffing.     

Before the ubiquity of infusion machines, regular rounds were undertaken to check that the infusions were running properly and on time.    

The price that is paid for machines that alarm is a chronic state of alertness by staff and patient.    75% of alarms are false alerts or require no immediate action or are simply ignored.

Alarms share the same characteristics as a human scream and activate within a human brain recognition of danger with resultant increase in staff stress.    

In a noisy environment, there is a cognitive cost in dealing with the subconscious processing of noises that distract.    

It reduces the ability to process auditory and visual information.    

And the desensitisation to back ground noise reduces alertness.    

The difficulty with alarms are that they all sound the same whether the problem is serious or minor.    

For ICU patients alarms can be so distracting that the median duration of unbroken sleep is three minutes or less.    

That is correct – three minutes or less of unbroken sleep.    

It is no surprise then that up to 75% of ICU patients experience a delirious episode at least once.    Lowering environmental noise levels may help patient’s sleep and improve staff concentration.    Building design and materials can reduce noise.    

Any increase in patients and staff will invariably lead to increasing noise.     

Designing units within ICU that mimic less crowded spaces is a design for the future.    

Yet that is only one part of the solution – staff education is just as important.   

 Quiet periods were previously practiced in hospitals to allow patients to recuperate before open visiting hours were introduced.    

Alarm thresholds and volumes could be individualised.    

Visual alerting when noise levels become too high could be implemented.    

Also haptic or vibration feedback from a smart phone may be another way to draw attention to a high level of noise.    

The fact that patients have accepted that hospitals are noisy places and they have no expectations of silence and rest does not mean that it is OK.    

It is a quality of care issue and needs to be addressed.  

To learn more about hospital noise,

Sasso, L., Bagnasco, A., Aleo, G., Catania, G., Dell’Agnello, D., Currie, K. and Timmins, F. (2016), Editorial: Noise on hospital wards – what have we learned?. J Clin Nurs, 25: 891–893.