Detecting early signs of skin damage using non-invasive biophysical parameters

Abstract

Pressure ulcers (PUs) and incontinence-associated dermatitis (IAD) are types of skin damage that result from prolonged exposure to external insults including pressure, shear, friction, and moisture. The clinical symptoms, which often lead to chronic wounds, can involve erythema, skin swelling, oedema and skin breakdown. It is imperative to detect early signs of these conditions prior to chronic damage. However, subjective visual and tactile skin assessments typically used by clinicians lack predictive capability. Objective biophysical approaches have been suggested to provide the means of monitoring the early signs of damage, although further evidence is required to establish their performance in a range of clinically relevant situations. The goal of the doctoral research is to utilise an array of non-invasive biophysical sensors to understand the pathophysiological changes in the skin following different insults associated with PUs and IAD.
This thesis presents the results from a series of complimentary retrospective and prospective studies. These involved the analysis of established data from the host lab, a survey of skin damage resulting from the application of personal protective equipment (PPE), and two prospective lab-based studies. The former involved the recruitment of able-bodied volunteers and healthcare workers who were exposed to moisture and mechanical loads through incontinence pads and lying postures, and respirator protective equipment (RPE), respectively. These findings were used to inform a cohort study of hospitalised patients with stage I pressure ulcers.
Results revealed that prolonged exposure of the skin to mechanical loads and moisture can disrupt its barrier function, as evidenced by enhanced values of trans-epidermal water loss and stratum corneum hydration. Furthermore, among the biophysical skin parameters evaluated, TEWL and hydration were able to distinguish between compromised and healthy adjacent skin sites, but not between different insults. During a COVID-19 study of adverse reactions to PPE, cohorts of healthcare workers revealed that they had indentation marks, pressure damage, itchiness, rashes, and spots. The subsequent study of biophysical changes in skin health identified distinct changes in skin barrier function and hydration over vulnerable bony landmarks on the face (bridge of the nose) associated with RPE application. Findings from this study showed that the outputs of these parameters were influenced by the subject extrinsic and intrinsic factors, namely body mass index and daily working hours. The final clinical study revealed highly localised changes (<5mm) in skin barrier function over the pressure ulcer site. In contrast to the lab-based studies, skin hydration did not differentiate between healthy and damaged skin. Complementary analyses also revealed the important role of inflammatory cytokines in the early detection of skin compromise, as well as the potential of epidermal corneocytes as novel biomarkers reflective of changes in skin health.
The use of biophysical tools to monitor local changes in skin health could represent an important adjunct to clinical practice, which currently relies on subjective skin assessment. However, to support its wider translation in different care settings, future research is required to analyse time-dependent changes in these parameters, in both acute and long-term care facilities, to assess the prognostic value when determining skin status (healing or progressing to wounds). In addition, engagement with healthcare workers to analyse the barriers and facilitators to adoption along with the cost-effectiveness of introducing these tools is needed prior to wider adoption in practice.

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Identifiers

ORCID for Peter Worsley: orcid.org/0000-0003-0145-5042

ORCID for Davide Filingeri: orcid.org/0000-0001-5652-395X

ORCID for Daniel L Bader: orcid.org/0000-0002-1208-3507

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