The aetiology of medical device-related pressure ulcers and how to prevent them

This article provides an introduction to the aetiology of medical device-related pressure ulcers (MDRPUs), describes the vicious cycle that leads to these injuries and highlights bioengineering methodologies and findings that connect the aetiology to the clinical practice of preventing MDRPUs. Specifically, the vicious cycle of MDRPUs is triggered by the sustained tissue deformations induced by a skin-contacting device. The primary, deformation-inflicted cell damage leads to a secondary inflammatory-oedema-related damage and then to tertiary ischaemic damage. Each of these three factors contributes to cumulative cell death and tissue damage under and near the applied device. The damage therefore develops in an escalated manner, as a result of the added contributions of the above three factors. This phenomenon is exemplified through two common clinical scenarios. First, through the use of continuous positive airway pressure (CPAP) masks, which are being applied extensively in the current COVID-19 pandemic, and, second, through the use of doughnut-shaped head positioners, which are applied to surgical patients and sometimes to bedridden individuals who receive intensive care in a supine position. These two medical devices cause intense, localised mechanical loads in the facial skin and underlying tissues (CPAP mask) and at the occipital scalp (doughnut-shaped positioner), where the soft tissues cannot swell in response to the inflammatory oedema as, in both cases, the tissues are sandwiched between the device and the skull. Accordingly, the two device types result in characteristic MDRPUs that are avoidable through appropriate prophylactic interventions, that is, preventive dressings under the CPAP mask and replacement of the doughnut device by a soft, shape-conforming support aid to alleviate and disperse the localised soft tissue deformations. Hence, understanding the aetiology of MDRPUs targets and focuses effective clinical interventions.