Despite some promising findings, there was insufficient evidence to confidently recommend the use of any of these measures as predictors of wound healing. pH measurement appeared as the most practical method for use in clinical practice to indicate wound healing outcomes. Further research is required to increase the strength of evidence and develop a greater understanding of wound healing dynamics.

Current detection of pressure ulcers relies on visual and tactile changes at the skin surface, but physiological changes below the skin precede surface changes and have a significant impact on tissue health. Inflammatory and apoptotic/necrotic changes in the epidermal and dermal layers of the skin, such as changes in interstitial fluid (also known as subepidermal moisture (SEM)), may precede surface changes by 3-10 days. Those same epidermal and subepidermal changes result in changes in the electrical properties (bioimpedance) of the tissue, thereby presenting an objective, non-invasive method for assessing tissue damage. Clinical studies of bioimpedance for the detection of pressure ulcers have demonstrated that changes in bioimpedance correlate with increasing severity of pressure ulcer stages. Studies have also demonstrated that at anatomical locations with pressure ulcers, bioimpedance varies with distance from the centre of the pressure ulcers. The SEM Scanner, a handheld medical device, offers an objective and reliable method for the assessment of local bioimpedance, and therefore, assessment of tissue damage before signs become visible to the unaided eye. This literature review summarises pressure ulcer pathophysiology, principles of bioimpedance and clinical research using bioimpedance technology to assess pressure ulcers.

Aim: To identify how activity and mobility lead to pressure ulcer development, using two objective assessments, one for mobility and one for early pressure ulcer detection.Methods: 150 older persons from long-term settings were followed up for 20 days, using an observational, quantitative, prospective study design. The study was conducted in accordance with the Strengthening the Reporting of Observational Studies in Epidemiology statement. Visual skin assessment and sub-epidermal moisture assessments were undertaken daily. Activity was measured using the Braden subscale.Further, a mobility profile of the participants was identified using a piezoelectric motion sensor which provided a "movement score" (mean number of movements/hour).Movement scores from 22 healthy participants were also measured to better understand the mobility profile in a healthy population.Results: Pressure ulcer incidence using visual skin assessment was 12.7% (low movers = 6.7%; high movers = 6%) and 78.7% using sub-epidermal moisture assessment (low movers = 40.0%; high movers = 38.7%). Sub-epidermal moisture assessment detected pressure ulcers on average 8.2 days before they appeared visually on the skin's surface. Pressure ulcer detection was 25 times greater using sub-epidermal moisture compared to visual skin assessment. Considering the results of the "movement level" assessment using the motion sensor technology, of all those who were determined to be immobile by Braden, 18.8% were assessed as high movers.Discussion & Conclusion: Pressure ulcers occurred both in low and high movers, which was unexpected as a similar finding has not been previously reported in the literature.