סמינר המחלקה להנדסה ביו-רפואית

Summary

The Science of Prevention of Device-Related Pressure Ulcers

Lea Peko

Pressure ulcers (PUs) are localized damage to skin and/or underlying tissues resulting from sustained pressure, including the shear. Approximately one-third of all hospital-acquired PUs are associated with the use of medical devices (such as oxygen masks), including also non-medical objects. The risk of developing such device-related PUs (DRPUs) may be reduced by using protective means, e.g. prophylactic dressings applied as tissue protectors at the body-device contact sites. However, the scientific knowledge of the mechanisms through which protective means may provide tissue protection against DRPUs is still poor. A revolutionary approach for DRPU prevention could be to develop a methodology for evaluating tissue health status during interaction with different devices associated with a risk for DRPUs using non-invasive technologies that can accurately detect biomechanical markers associated with DRPU, such as excessive force, thermal and subepidermal moisture (SEM) changes. These technologies provide important physiologically and clinically-relevant information that can be utilized as an adjunct to the current clinical care for prevention. Accordingly, the primary objective of this doctoral research work is to explore the evaluation of technology-based strategies in the context of DRPU prevention, using an integrated mechanobiological, thermodynamic and physiological approach. For these purposes, we employed a methodology which included (i) interface force measurements at the skin-mask contact sites, (ii) computational head model simulating the tissue exposure to loads applied by the mask with vs. without the dressing cuts, and (iii) infrared thermography (IRT) to detect skin thermal changes under the mask. We found that application of the dressings is biomechanically effective in protecting the tissues from mechanical loads while using medical devices. Further, IRT is demonstrated to be suitable for the quantitative evaluation of microclimate conditions at the skin-device contact sites. Next, we experimentally evaluated the feasibility of an non-invasive technology in detecting physiological changes, e.g. variations in SEM contents within the tissues mimicking DRPU due to sustained loading by the mask, which confirms its clinically evident efficacy in early-detection of DRPU. In order to address the considerable rise of DRPUs during the current coronavirus disease 2019 pandemic, we computationally provided solid biomechanical evidence to support the clinical practice in applying prophylactic dressings to protect the patients. Lastly, we report here a novel experimental evaluation composed of force, temperature and SEM data collection to investigate differences between these biomechanical factors, known to be associated with skin irritation, for the commonly used KN95 and surgical masks during the current pandemic. We found that a surgical mask is less irritating to facial skin than the KN95 respirator, as it applies lower forces and facilitates faster return of facial temperatures to their basal levels. Further, we demonstrated that the use of dressings under PPE considerably reduced localized forces and did not worsen the thermal and SEM conditions at the skin-device contact sites. This study, being more relevant than ever, is a major contribution to improvement of PPE design, as it details the physiological measurement methodologies needed for a quantitative comparison of the effects of different PPE types on facial skin status.