Measuring subepidermal moisture to detect early pressure ulcer development: a systematic review

Pressure ulcer risk assessment in the ICU. Is it time for a more objective measure?

BACKGROUND

The Braden scale, one of the most widely used risk assessment tools is often criticized when used in the Intensive Care Unit. Most patients in the Intensive Care Unit are at risk of pressure ulcer development meaning that the Braden score will usually indicate high risk for these patients. This study set out to determine the correlation between Sub-Epidermal Moisture measurements and Braden scores among Intensive Care Unit patients.

METHODS

This study employed an observational research design. Braden score was assessed on all study days (1-5), in addition to visual skin assessment and Sub-Epidermal Moisture measurements at the sacrum and heels. Sub-Epidermal Moisture measurements were categorised as low (<0.5), borderline abnormal (≥0.5), and high (≥0.8). Correlation was assessed between Sub-Epidermal Moisture levels and Braden scores.

RESULTS

A total of 53 participants were recruited. The median (interquartile range) baseline Braden score was 9 (9-10) and 81 % (n = 43) of participants were at very high/high risk of pressure ulcer development. Braden scores remained relatively constant over time with little fluctuation in scores. 19 % (n = 10) of patients had normal (<0.5) Sub-Epidermal Moisture delta measurements on enrolment, and all developed abnormal measurements by day 2. There were no significant correlations between Braden scores and Sub-Epidermal Moisture measurements.

CONCLUSION

Although this was not its original intention, a missing link with the Braden scale is that it does not provide information on how patients are responding to the adverse effects of pressure and shear forces. Furthermore, in patients who are critically unwell, most patients are classified as being "at risk" of pressure ulcer development. Therefore, an objective measure of how patients are responding to pressure and shear forces at different anatomical areas is needed.

IMPLICATIONS TO CLINICAL PRACTICE

Sub-Epidermal Moisture measurements can offer more information, not only on identifying those who are at risk, but also how those patients are tolerating this risk at different anatomical sites.

Shedding new light for nurses: Enhancing pressure injury prevention across skin tones with sub-epidermal moisture assessment technology

AIM(S)

To assess the effectiveness of sub-epidermal moisture (SEM) assessment technology in the detection of early-stage pressure damage in a critical care unit (CCU) and dark skin tone patients and its impact on hospital-acquired pressure injury (HAPI) incidence.

DESIGN

Quality improvement study employing Kurt Lewin's change model emphasizing planning, implementation, evaluation and sustainable change.

METHODS

The study evaluated 140 adult patients admitted to the CCU over a 24-week period, from July to December 2022. Retrospective analysis of standard PI care pathways was performed in 90 patients admitted during a 12-week pre-implementation period. Fifty patients were admitted through the subsequent 12-week implementation period. SEM assessments were performed daily at the sacrum and heels and interventions were applied based on SEM assessments; SEM delta ≥0.6 indicating localized oedema or persistent focal oedema. Statistical analyses were performed on anonymized data.

RESULTS

Pre-implementation HAPI incidence was 8.9% (N = 8/90). All eight patients were African American with varying skin tones. A 100% reduction in HAPI incidence was achieved in the implementation period which included 35 African American patients. The relative risk of HAPI incidence was 1.6 times higher in the pre-implementation group.

CONCLUSION

Implementing SEM assessment technology enabled equitable PI care for all population types and resulted in a 100% reduction of PIs in our CCU. Objective SEM assessments detected early-stage PIs, regardless of skin tone and enabled providing interventions to specific anatomies developing tissue damage as opposed to universal preventive interventions.

IMPLICATIONS

PI care pathways relying on visual and tactile skin assessments are inherently biased in providing equitable care for dark skin tone patients. Implementing SEM assessments empowers healthcare practitioners in driving objective clinical interventions, eliminates bias and enables positive PI health outcomes.

IMPACT

Implementing SEM assessment technology had three main effects: it detected early tissue damage regardless of skin tone (detection effect), enabled anatomy-specific interventions (treatment effect) and prevented PIs across all population types (prevention effect). The authors have adhered to the Standards for Quality Improvement Reporting Excellence (SQUIRE) 2.0 guidelines.

PATIENT OR PUBLIC CONTRIBUTION

No patient or public contribution. What does this paper contribute to the wider global clinical community? Addressing health inequities in pressure injury prevention; Demonstrated effectiveness across patient populations; Resource optimization and enhanced patient safety.

A systematic review on the impact of sub-epidermal moisture assessments on pressure ulcer/injury care delivery pathways

To assess all published studies which describe what happens to the delivery of pressure ulcer/injury (PI/PU) care pathways as a result of detecting raised sub-epidermal moisture (SEM) delta (∆ ≥ 0.6). We undertook a systematic review of the literature, and included original research studies using either a prospective or retrospective study design that report the impact that assessment using SEM assessments have on healthcare practitioners' delivery of PI/PU care pathways in adults at risk of developing PI/PUs. The review protocol was registered on PROSPERO (CRD42023416975). A literature search was conducted in May 2023, using PubMed, CINAHL, Scopus, Cochrane, EMBASE, Web of Science and Science Direct databases. Data were extracted using a data extraction tool including elements such as country, setting, sample size, intervention, control and quality appraisal was undertaken using the Evidence-based Librarianship. We identified nine papers published between 2017 and 2022. The majority of these studies were conducted in England (n = 6; 67%). The systematic review included studies conducted across multiple care settings including acute care, medical-surgical units, and palliative care, highlighting the importance of PI/PU prevention and management across diverse patient populations. The PI/PU care pathways implemented in the studies varied, but commonly included elements such as the application or increased use of pressure-redistributing mattresses/cushions, implementation of repositioning plans, management of incontinence and moisture, regular skin inspection, and assessment of patient mobility. Out of the nine studies identified, seven reported PI/PU incidence. A meta-analysis of seven studies (N = 18 451) demonstrated a statistically significant reduction in visual PI/PU development in favour of SEM-guided care pathways compared to usual care (the odds ratio = 0.36 [95% confidence interval: 0.24-0.53, p < 0.00001]). This systematic review provides evidence that implementing SEM assessments in patients at risk of developing PI/PUs prompts anatomy-specific clinical actions. The subsequent implementation of enhanced and targeted skin care interventions leads to consistent and sustained reductions in hospital-acquired PU incidence. The findings emphasise the importance of incorporating SEM assessments as part of comprehensive PI/PU prevention strategies in all care settings and patient populations. This systematic review is limited by the predominance of observational studies and variable study quality. Future research should focus on randomised trials in different care settings that monitor the efficacy of preventive interventions and their impact in reducing PI/PU incidence when implemented based on SEM assessments.

Enhanced Skin Assessment Methodology to Detect Early Tissue Damage and Prevent Pressure Injuries

PURPOSE

The purpose of this study was to evaluate a skin assessment technique, subepidermal moisture (SEM) assessment, to assess, identify, and prevent pressure injuries (PIs) in critically ill adults.

DESIGN

This was a retrospective, descriptive, comparative research study.

SUBJECTS AND SETTING

The sample comprised 69 critically ill adults; their mean age was 58.8 years (SD 18.1 years). The majority were male (n = 40, 58%), 29 (42%) were African American (AA), and 36 (52%) were White. The study setting was a surgical trauma intensive care unit (STICU) in a southern US Gulf Coast academic level I trauma hospital. Data were collected from September to November 2021.

METHODS

We conducted a retrospective medical record review of subjects who had undergone SEM assessment. We also collected demographic and pertinent clinical information, including Braden Scale cumulative scores and subscale scores, documented PI prevention interventions, and PI occurrence and characteristics if developed within 7 days of SEM measurement. We also evaluated whether PI prevention interventions were appropriate. To examine nurse perception of the SEM device, we conducted a web-based survey of nurses providing care in our facility's STICU. Comparison of responses was done using Fisher's test or Chi-square test, and the mean responses from groups were compared using t test.

RESULTS

Thirty-five (57%) subjects had a sacral SEM delta ≥0.6; 14 (40%) were AA; 20 (57%) were White; and 11 (31%) had a hospital-acquired PI (HAPI) or present-on-admission (POA) PI. Among the 14 HAPI and POA PI subjects with sacral SEM delta, 11 (79%) had sacral SEM delta ≥0.6. Among 26 AA subjects with sacral SEM delta, 5 had a HAPI or POA PI, and of those, 4 (80%) had sacral SEM delta ≥0.6. A significant and negative correlation was observed between cumulative Braden Scale scores on day 2 and sacral SEM delta (r = -0.28, P = .03) and R heel delta (r = -0.29, P = .03) scores, indicating higher PI risk. Of the 35 patients with a sacral SEM delta ≥0.6, 24 (69%) subjects did not have appropriate PI prevention interventions. Nurses (n = 13) indicated that the SEM device was easy to use and helped them perform an accurate skin assessment on patients with darker skin tones.

CONCLUSIONS

This study demonstrates that SEM technology is beneficial to address racial disparities in skin assessment, enhance skin assessment accuracy beyond existing PI care, improve the accuracy of risk assessment, and promote appropriate location-specific PI prevention interventions.

The correlation between sub-epidermal moisture measurement and other early indicators of pressure ulcer development-A prospective cohort observational study. Part 1. The correlation between sub-epidermal moisture measurement and ultrasound

The correlation between sub-epidermal moisture (SEM) and other early indicators of pressure ulcer (PU) development is yet to be determined. This three-part series aims to bridge this knowledge gap, through investigating SEM and its correlation with evidence-based technologies and assessments. This article focuses on the correlation between SEM and ultrasound. A prospective cohort observational study was undertaken between February and November 2021. Patients undergoing three surgery types were consecutively enrolled to the study following informed consent. Assessments were performed prior to and following surgery for 3 days at the sacrum, both heels and a control site, using a SEM scanner and high-frequency ultrasound scanner (5-15 MHz). Spearman's rank (rs ) explored the correlation between SEM and ultrasound. A total of 60 participants were included; 50% were male with a mean age of 58 years (±13.46). A statistically significant low to moderately positive correlation was observed between SEM and ultrasound across all anatomical sites (rs range = 0.39-0.54, p < 0.05). The only exception was a correlation between SEM and ultrasound on day 0 at the right heel (rs  = 0.23, p = 0.09). These results indicate that SEM and ultrasound agreed in the presence of injury; however, SEM was able to identify abnormalities before ultrasound.

The effect of prolonged 60° head of bed elevation on sacral subepidermal oedema in healthy adults: A quantitative prospective exploratory study

Head of bed elevation is used to manage some medical and surgical conditions however this may increase a patient's risk of sacral pressure injuries. Novel point-of-care technologies that measure subepidermal moisture can identify changes in localised subepidermal oedema and potential pressure injury risk. This prospective exploratory study investigated variations in sacral subepidermal oedema in healthy adults during 120-min of 60° head of bed elevation. Sacral subepidermal oedema was measured at 20-min intervals using the Provisio® subepidermal moisture scanner. Descriptive analysis, one-way repeated measures analysis of variance and an independent t-test were conducted. Slightly more male volunteers (n = 11; 55%) were recruited and the sample mean age was 39.3 years (SD 14.7) with an average body mass index of 25.8 (SD 4.3). Little variation in the mean sacral subepidermal moisture of healthy adults was observed. There was a statistically significant difference in the mean sacral subepidermal moisture measurements between males and females (Mean difference 0.18; 95% confidence intervals: 0.02 to 0.35; P = .03). Healthy adults can tolerate prolonged 60° head of bed elevation without developing increased subepidermal sacral oedema. This warrants further investigation in other populations, in various positions and over different time periods.

Validation of a sub-epidermal moisture scanner for early detection of pressure ulcers in an ex vivo porcine model of localized oedema

Pressure ulcers (PUs) remain a chronic health problem with severe impacts on healthcare systems. Early detection is crucial to providing effective interventions. However, detecting PUs currently relies on subjective tissue evaluations, such as visual skin assessment, precluding interventions prior to the development of visible tissue damage. There is an unmet need for solutions that can detect early tissue damage before visual and tactile signs occur. Assessments based on sub-epidermal moisture (SEM) measurements represent an opportunity for robust and objective early detection of PUs, preventing broken skin PUs in more high-risk patients at high-risk anatomical locations. While SEM assessment technology has been validated in computational, bench and tissue phantom models, validation in soft tissue was absent. In this study, we successfully validated the ability of a commercially available SEM assessment device to measure and detect sub-epidermal moisture changes in a novel ex vivo porcine soft tissue model of localised oedema. When controlled and incremental fluid volumes (Phosphate Buffer Solution) were injected into porcine soft tissues, statistically significant differences were found in SEM values between fluid-injected sites, representing an inflammatory oedematous condition, and healthy tissue control sites, as measured by the SEM device. The device provided reproducible readings by detecting localised oedema changes in soft tissues, reflecting the build-up of fluid as small as 1 ml into the underlying tissue. Spatial characterization experiments described the ability of the device technology to differentiate between healthy and oedematous tissue. Our findings validate the use of SEM assessment technology to measure and quantify localized oedema.

Modelling the cost-effectiveness of subepidermal moisture measurement as part of a process of assessment and intervention to prevent hospital-acquired pressure ulcers

Skin tissue assessment is traditionally used to identify early signs of pressure damage from changes observed at the skin surface. However, the early onset of tissue damage induced by pressure and shear forces is likely to be on soft tissues beneath the surface of the skin. Subepidermal moisture (SEM) is a biophysical marker for the detection of early and deep pressure-induced tissue damage. Measurement of SEM can detect early pressure ulcers up to 5 days before visible skin changes occur. The aim of this study was to evaluate the cost-effectiveness of SEM measurement compared with visual skin assessment (VSA). A decision-tree model was developed. Outcomes are the incidence of hospital-acquired pressure ulcers, quality-adjusted life-years (QALYs) and costs to the UK National Health Service. Costs are at 2020/21 prices. The effects of parameter uncertainty are tested in univariate and probabilistic sensitivity analysis. In a representative NHS acute hospital, the incremental cost of SEM assessment as an adjunct to VSA is -£8.99 per admission, and SEM assessment is expected to reduce the incidence of hospital-acquired pressure ulcers by 21.1%, reduce NHS costs and lead to a gain of 3.634 QALYs. The probability of cost-effectiveness at a threshold of £30 000 per quality-adjusted life year is 61.84%. Pathways that include SEM assessment make it possible to implement early and anatomy-specific interventions which have the potential to improve the effectiveness of pressure ulcer prevention and reduce healthcare costs.

Current Perspectives on Pressure Injuries in Persons with Dark Skin Tones from the National Pressure Injury Advisory Panel

BACKGROUND

Pressure injury (PI) development is multifactorial. In patients with dark skin tones, identifying impending PIs by visual skin assessment can be especially challenging. The need for improved skin assessment techniques, especially for persons with dark skin tones, continues to increase. Similarly, greater awareness of the need for inclusivity with regard to representation of diverse skin colors/tones in education materials is apparent.

OBJECTIVE

To provide current perspectives from the literature surrounding skin assessment and PI development in patients with dark skin tones.

METHODS

The following elements will be discussed through the lens of skin tone: (1) historical perspectives of PI staging from the National Pressure Injury Advisory Panel, (2) epidemiology of PI, (3) anatomy and physiology of the skin, (3) skin tone assessment and measurement, (4) augmented visual assessment modalities, (5) PI prevention, (6) PI healing, (7) social determinants of health, and (8) gaps in clinician education.

CONCLUSIONS

This article highlights the gap in our clinical knowledge regarding PIs in patients with dark skin tones. Racial disparities with regard to PI development and healing are especially clear among patients with dark skin tones. Skin tone color assessment must be standardized and quantifiable in clinical education, practice, and research. This work is urgently needed, and support from private and governmental agencies is essential.

Feasibility of Skin Water Content Imaging Using CMOS Sensors

Pressure injuries (PI) result from pressure-induced damage to the skin and underlying tissues. Currently, Stage I PI are detected using visual skin assessments. However, this visual method is unable to detect skin color changes in persons with darkly pigmented skin, which results in a higher Stage II-IV PI incidence and PI-associated mortality in persons with a darker complexion. Thus, a more objective method of early-stage PI detection is of great importance. Optical spectroscopy is a promising modality for the noncontact diagnosis and monitoring of skin water content, capable of detecting edema and Stage I PI. The scope of the current study is to assess the feasibility of imaging the water content of the skin using Si-based sensors. We have considered two primary cases: the elevated bulk water content (edema) and localized water pool (e.g., blood vessels). These two cases were analyzed using analytical models. We found that detecting the watercontent contrast associated with edema in tissues is within the reach of Si-based sensors. However, although the effect is expected to be detectable even with consumer-grade cameras, with the current state of technologies, their use in real-world conditions faces numerous technical challenges, mainly due to the narrow dynamic range.