Dynamic Mattresses

Pressure ulcer remain a major issue for patients in and out of hospitals around the country with over 1,300 new pressure ulcers every month in the UK (NHS Improvement, 2019). Pressure ulcers make up 7% of the wounds treated by the NHS and cost the NHS up to £1.4 million each year (JCN, 2018).

I’m not going into every right and wrong of pressure ulcer prevention in this post, maybe I’ll save that one for the future, but I am going to focus on the pressure relieving mattress called a dynamic or air flow mattress (AFM).

What are they?

This piece of equipment is the big sister of those lovely butt-dented foam mattresses that normally populate hospital beds. These are made up of a number of separate ‘cells’ under the main cover that inflate and deflate independently using a motor in an attempt to offload different areas of the patient’s body at any time. This allows the skin and underlying tissues some relief from the constant pressure of the body vs gravity.

When are they used?

Current consensus is that these mattresses should be reserved for those patients either at high risk of skin damage or already have pressure damage. A normal foam mattress should be suitable for more patients either with intact skin or low to medium risk (NPUAP, 2014).

Do they work?

The little evidence that is available about AFM use  is slim pickings, and the stuff that does exist is generally of poor quality. Cochrane have done robust systematic reviews about their use and found that they do a good job at preventing pressure ulcers (McInnes et al., 2015)

Tips and Tricks

During my short career in nursing I’ve noticed a few pitfalls when using AFMs, so we’ll address that here:

Tucking the sheets

I know, hospital corners. But unfortunately tucking sheets in really tight around an AFM can reduce its effectiveness by firstly forming a snug hammock above the cells, but also not allowing the mattress to inflate fully. Allowing the sheets to be a bit looser ensures that the patient is in contact with the cells, and avoid using tight fitted sheets, excess bedding or a ton of incontinence pads (although don’t do this one anyway…).

Changing the weight

Contrary to popular belief, the weight buttons on the pump are not a decorative feature. The mattress will work much more efficiently if it’s calibrated to the persons weight, and not just stuck on the highest setting.


If at any time you’re moving a patient, and this could be rolling them on the bed, moving them to another bed or moving the bed itself, stick the mattress on static (there should be a separate button next to the weights). Not only will this make the whole experience easier as the patient’s body won’t sink into different parts of the mattress you don’t want them in. It should also make it a tad more comfortable for them.

Check under the covers

I know that everyone totally checks inside every mattress when they clean it between patients/after accidents, but seriously, check them! I’ve seen some nasty things (normally bodily fluids) hidden under the cover, which is always disconcerting when I know the last patient wasn’t incontinent etc. This also allows you to check for any damage to the cells and get them fixed so they don’t put the next patient at risk. If someone is going to be on it long-term, there’s no harm giving the inside a glance once a week just to make sure everything’s still in place.


Each brand will have their CPR valve located in a different area of the mattress. Find out where they are and how to open them for emergencies, some have little dials to turn and others a pull-out tab. Also worth making sure this valve is closed before inflating it in the first place too.

So what?

AFMs can be a really great piece of equipment when used correctly, but that’s the key point, you have to use them properly and following the manufacturers guidance. And like every tool in the nursing arsenal, there’s nothing better than using your clinical judgement; just because your patient is safety stored away on their fancy new dynamic mattress, does not mean that they will never develop a pressure sore. Also don’t forget about your patient: if they’re not comfortable on the mattress, no matter how high they’re risk, if they’re not getting any sleep this could put them at even more risk.


JCN (2018) ‘Realities of Woundcare 2017’, Journal of Community Nursing, 32(1). doi: 10.1111/iwj.12814.

McInnes, E. et al. (2015) ‘Support surfaces for pressure ulcer prevention’, Cochrane Database of Systematic Reviews, (9). doi: 10.1002/14651858.CD001735.pub5.

NHS Improvement (2019) Stop the Pressure. Available at: http://nhs.stopthepressure.co.uk/ (Accessed: 14 April 2019).

Nightingale, F. (1859) Notes on Nursing: What it is and What it is Not. London: Harrison.

NPUAP (2014) ‘Prevention and Treatment of Pressure Ulcers’. Available at: http://www.npuap.org/wp-content/uploads/2014/08/Quick-Reference-Guide-DIGITAL-NPUAP-EPUAP-PPPIA-Jan2016.pdf (Accessed: 16 June 2017).


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