Pressure ulcers

Pressure ulcers can negatively impact on the patient’s quality of life by causing pain, infection, and prolonged stays in hospital (White, 2014). Additionally, there is a huge cost to the healthcare system, mean annual costs to the NHS are estimated to be more than £8,700 per pressure ulcer (Guest et al, 2018). To prevent pressure ulcers occurring, it is important that all healthcare professionals have a good understanding of what a pressure ulcer is and the underlying factors that can cause them. It is essential to understand that some people are more susceptible to pressure and shear forces than others, therefore correct management should be implemented.

A pressure ulcer can be defined as ‘localised damage to the skin and/or underlying tissue, usually over a bony prominence (or related to a medical or other device), resulting from sustained pressure (including pressure associated with shear). The damage can be present as intact skin or an open ulcer and may be painful’ (NHS Improvement, 2018a). Pressure damage may not be immediately visible on the surface of the skin; as tissue ischaemia and cell death from sustained pressure and shear forces occurs in the deeper tissues first (Gefen et al, 2022).

Pressure ulcers occur as a result of two forces acting at the same time – pressure and shear.

Pressure

Refers to the sustained direct force between a bone and the surface that the patient is in contact with. The tissues between these hard structures become compressed resulting in occlusion of the blood vessels. This starves the tissue of oxygen and nutrients; ultimately resulting in cell death and tissue ischaemia (Gefen et al, 2022). This can occur in as little as 2 hours.

Shear

Forces occur when pressure distorts the surrounding tissue causing the capillaries and cells to stretch and tear. As the cells rupture, cell fluid leaks into the surrounding tissues causing oedema and bleeding from small arterioles and capillaries (Gefen et al, 2022). This is increased if there is also an external shearing force, such as a person sliding down a bed or chair.

Before any visible signs of pressure ulcers are present, many patients experience pain or altered sensations over the affected area (Todd, 2021; Wilson et al, 2021). There may be a difference in the local temperature of the skin (either warmer or cooler to touch; Morrow, 2021) and the tissue may also feel hard or boggy as a result of oedema and inflammation. In the early stages, there may be alterations in localised skin colour; either redness in pale skin tones or mauve/ grey hues in dark skin tones (Black et al, 2016; Dhoonmoon et al, 2021).

Pressure ulcers are categorised depending on the depth of tissue that has been damaged. Recognising the different categories allows clinicians to accurately diagnose, document and plan care for their patients.