Lateral pressure equalisation as a principle for designing support surfaces to prevent deep tissue pressure ulcers

Autoři: Colin J. Boyle aff001;  Diagarajen Carpanen aff001;  Thanyani Pandelani aff001;  Claire A. Higgins aff001;  Marc A. Masen aff002;  Spyros D. Masouros aff001
Působiště autorů: Department of Bioengineering, Imperial College London, London, United Kingdom aff001;  Department of Mechanical Engineering, Imperial College London, London, United Kingdom aff002
Vyšlo v časopise: PLoS ONE 15(1)
Kategorie: Research Article


When immobile or neuropathic patients are supported by beds or chairs, their soft tissues undergo deformations that can cause pressure ulcers. Current support surfaces that redistribute under-body pressures at vulnerable body sites have not succeeded in reducing pressure ulcer prevalence. Here we show that adding a supporting lateral pressure can counter-act the deformations induced by under-body pressure, and that this ‘pressure equalisation’ approach is a more effective way to reduce ulcer-inducing deformations than current approaches based on redistributing under-body pressure. A finite element model of the seated pelvis predicts that applying a lateral pressure to the soft tissue reduces peak von Mises stress in the deep tissue by a factor of 2.4 relative to a standard cushion (from 113 kPa to 47 kPa)—a greater effect than that achieved by using a more conformable cushion, which reduced von Mises stress to 75 kPa. Combining both a conformable cushion and lateral pressure reduced peak von Mises stresses to 25 kPa. The ratio of peak lateral pressure to peak under-body pressure was shown to regulate deep tissue stress better than under-body pressure alone. By optimising the magnitude and position of lateral pressure, tissue deformations can be reduced to that induced when suspended in a fluid. Our results explain the lack of efficacy in current support surfaces and suggest a new approach to designing and evaluating support surfaces: ensuring sufficient lateral pressure is applied to counter-act under-body pressure.

Klíčová slova:

Deformation – Fats – Finite element analysis – Pelvis – Stiffness – Ulcers – Muscle tissue – Soft tissues


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