Understanding Shear Forces and Friction

Did you know, it’s not just pressure that leads to pressure ulcers?

 

Pressure ulcers typically develop in vulnerable individuals who are bedridden or otherwise immobile for extended periods of time. While sustained pressure is an obvious cause, there are two other adverse factors which also contribute to the formation of a pressure ulcer. These are called shear forces and friction, and understanding how these forces work can help in both controlling the ulcers, and preventing them.

 

Shear forces are present in many day to day movements, and occur when layers of skin move in opposite directions, causing tissue deformation. This happens in situations where the skin is forced to remain stationary, which deeper tissues and bones move, for example when a person slides down in a bed or a chair. In this movement, the skeleton moves downward due to gravity, but the skin on the surface remains held in place due to contact with the furniture. This movement creates stress within the layers of tissue, particularly in areas with bony prominences like the sacrum or heels. 

 

The main impact of shear is the occurrence of stretching and tearing of tiny blood vessels, which then reduces blood flow to the affected area. With inadequate circulation, tissues receive less oxygen and nutrients, leading to cell death. Over time, this cell death results in the development of pressure ulcers. This leads to the formation of pressure ulcers in areas that don’t receive direct pressure, but are subject to shear forces.

 

Friction occurs when two surfaces rub against one another. This happens in situations where the skin drags across things like bed sheets or clothing. Repeated instances of friction can cause weakening in the epidermis, the skin’s outer layer. This leads to damage on the surface of the skin, compromising the protective barrier, making it more susceptible to the damaging impact of shear and pressure. Overall, this makes it more vulnerable to pressure ulcers.

 

Areas of the body that are more at risk of damage form friction include elbows, heels and back, where skin comes into contact with bed linens and seating more often. Decreasing friction is essential in minimising the risk of skin breakdown, and the subsequent development of pressure ulcers.

 

Thankfully, minimising the impact of sheer and friction are very similar to the way in which pressure is reduced. To reduce the impact of shear and friction, it’s important to use proper repositioning techniques, supportive cushions and specialised bed linens. Keeping the skin clean, dry and appropriately moisturised is also critical in maintaining skin integrity.

 

Alongside this, using appropriate equipment that supports the patient is paramount. At Wellell, we offer a full catalogue of appropriate pressure injury prevention solutions, crafted with materials that have been optimised to reduce the impact of shear forces and friction. Click the link below to discover our range: 

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