If carers are to provide appropriate protection for those in their care, they need to adopt a proactive approach to pressure ulcer protection. Equipment provides one part of a pressure ulcer prevention strategy. Equipment needs to enable carers to utilise resources such as staff to the maximum.

Most pressure relieving equipment is designed to act on the three mechanisms of pressure ulcer development; pressure, shear and friction. Pressure at any one point on the patients’ tissues needs to be reduced to the minimum. This is achieved by spreading load over the widest area possible. Even at low level, pressure can cause occlusion of tissue microcirculation. Tissues therefore need to be off-loaded periodically. This can be achieved by manually repositioning the patient therefore moving load from one area to another. Alternatively, the position of the surface interface can be changed regularly. Alternating air mattresses provide an automated method of helping achieve this. It should be noted that an alternating air mattress such as those produced by Squirrel Medical are designed to be used as an aid to care and not as a preventative / curative in their own right. This means that some patients will need regular repositioning, high levels of hydration and nutrition and sound levels of clinical / nursing intervention.

An alternating air mattress is made up of a series of air cells, which are inflated with an air pump. Pressures within each cell are set to be low enough to prevent total capillary occlusion whilst alternate cells offset the load. In addition, cells inflate in a cyclical manner – one set of cells supporting the patient whilst the others deflate, enabling the patients’ tissues to perfuse with oxygenated blood. The cycle changes approximately every ten minutes throughout the entire surface area of the bed. This action mimics the subtle movements we all make during rest and sleep, and which protect tissues.

Some air mattresses are supplied as overlays. These are placed on top of the standard mattress, enhancing the efficacy of the mattress and so reducing the risk of pressure ulcer formation. By utilising the standard mattress it eliminates the need to store equipment and reduces the cost of supplying a separate foam base. However the efficacy of the resultant system is compromised compared to a full air replacement system.

In full replacement systems, the original mattress is replaced with a complete air mattress, which is able to support the patient load. These systems are particularly useful in caring for the patient at higher risk of pressure damage. The level of air support enables greater conformability of the mattress to the patients profile and reduces the dependence on high quality base mattresses.

Clinical judgement should be used to ensure that the mattress does not risk “bottoming out” (whereby the pressure relieving support surface no longer supports the mass of the patient and their body weight ends up resting on the bed frame) due to patient weight / body mass or misuse of or defective equipment.