The relationship of subepidermal moisture and early stage pressure injury by visual skin assessment

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.

PRESSURE INJURIES IN ADULTS AND THE ELDERLY: A SCOPING REVIEW

ABSTRACT Objective: to map the evidence available in the literature on the development and characteristics of pressure injuries in adults and the elderly in primary and tertiary care settings. Method: retrospective analytical scoping review, carried out in 2023, in the Virtual Health Library, PUBMED, EMBASE, Web of Science, and SCOPUS databases. Registration (DOI 10.17605/OSF.IO/C63YM). Results: 29 studies were selected. The lesions were predominantly stage 2, located in the sacral, gluteal, and calcaneal regions, which developed during hospitalization, and some had recurrent lesions. Granulation tissue, liquefaction necrosis, and/or coagulation were found in the wound bed, with epithelialized, macerated, or a flaky edge. The presence of exudate was rarely reported. Conclusion: Based on these results, care can be improved by understanding the characteristics of pressure injuries, investing in therapies that optimize the healing process, improving patients’ quality of life, and reducing the cost of wound care.

Fluctuations in Detection Indicators and Their Significance for the Diagnosis of Early Pressure Injury in Rat Models

PURPOSE

The aim of this study was to identify the most meaningful diagnostic indicator for distinguishing blanchable erythema (BE) and stage 1 pressure injury (early PI) in an in vivo (rat) model.

DESIGN

A prospective case-control design was used to complete a horizontal and vertical comparison of detection indicators during the process of fading of BE or the deterioration of early PI into ulcer in rat models.

MATERIALS AND SETTING

The sample comprised 5 hairless rats with 20 injuries, of which 10 were BE and the other 10 were early PI. Data were collected at Nagano College of Nursing in 2020 in Nagano, Japan.

METHODS

The BE and PI rat models were established by subjecting the dorsal skin of a hairless rat to compression between 2 neodymium magnets for 45 minutes and 3.45 hours, respectively. The affected skin was observed based on the following: (1) photography, (2) hardness, (3) temperature, (4) moisture, and (5) spectrophotometric (a* value and ultraviolet [UV] reflectance) measurements. All measurements of BE were performed at the beginning to 60 minutes after decompression, and those for early PI were performed until 48 hours after decompression.

RESULTS

Multiple BE factors, such as the degree of erythema (macroscopy and a* value), hardness, temperature, and moisture, were found to have unstable fluctuations. Only UV reflectance gradually decreased from 6 hours and decreased significantly at 48 hours after decompression (P = .001 vs 1 hour). In contrast to early PI, erythema in BE obviously faded within 10 minutes.

CONCLUSIONS

Study findings indicate that a continuous decrease in UV reflectance can reflect the worsening of hemorrhage in early (stage 1) PI. In contrast, other indicators including photography, skin hardness, temperature, and moisture fluctuated and did not prove predictive for PI progression. The obvious fading of erythema in BE a short time after decompression can be used for clinical observations.

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.

Use of point-of-care subepidermal moisture devices to detect localised oedema and evaluate pressure injury risk: A scoping review

AIMS AND OBJECTIVES

To map current literature on bedside clinicians' use of point-of-care subepidermal moisture devices to identify increased pressure injury risk.

BACKGROUND

Pressure injuries are a substantial healthcare burden. Localised oedema occurs before visible or palpable changes, and therefore is a biomarker of increased pressure injury risk. Novel bedside technologies that detect localised oedema may aid early pressure injury preventative practices.

DESIGN

A scoping review.

METHODS

Arksey and O'Malley's six-step framework and the PRISMA-ScR guidelines guided this scoping review. CINAHL Complete, Embase, SCOPUS, Cochrane (wounds) and PubMed databases were searched for primary research and quality improvement projects published in English between 2008-2022. Included studies focused on clinicians' bedside use of subepidermal moisture devices to quantify localised oedema and pressure injury risk. The PAGER framework supported narrative synthesis of the extracted data.

RESULTS

Nine studies were selected from 1676 sources. Two point-of-care subepidermal moisture devices were identified in clinical use, largely by nurses. Inconsistent use and interpretations revealed significant knowledge gaps in clinical practice. Additionally, no included studies engaged patients or the public in their design.

CONCLUSIONS

Nurses recognise the value of objective measures in determining the risk of pressure injury and are the primary end-users of point-of-care subepidermal moisture devices. However, standardising procedural instructions and interpretive criteria to guide preventative measures requires further research.

RELEVANCE TO CLINICAL PRACTICE

International pressure injury clinical practice guidelines advocate for subepidermal moisture devices as an adjunct to routine clinical skin assessment, although little is known about bedside use. This scoping review reveals low adoption of such devices and the need to develop standardised procedures in their use and interpretation.

REGISTRATION

Open Science DOI https://doi.org/10.17605/OSF.IO/AB6Y5-7th of March 2022.

Sub epidermal moisture measurement and targeted SSKIN bundle interventions, a winning combination for the treatment of early pressure ulcer development

This study aimed to investigate the impact of sub epidermal moisture (SEM) measurement and targeted pressure ulcer (PU) prevention, versus visual skin assessment and usual care, on mean SEM delta scores and early pressure ulcer development in acute hospital patients. A quantitative quasi-experimental observational approach was used. A total of 149 at risk acute hospital patients took part, 78 treatment, and 71 control. SEM deltas were recorded daily for a maximum of 5 days using the SEM Scanner (Bruin Biometrics LLC, Los Angeles, California), on three sites: the sacrum, the right heel, and the left heel, with enhanced and targeted PU prevention interventions occurring in those with an elevated SEM delta scores in the treatment group. Intention to treat analysis was used to guide the final composition of results. SEM PU represents PU development as identified by 2 days of sustained abnormal SEM delta scores, ≥0.5, after day one. The mean number of days completed by participants was just under 4 days, participants had many different comorbidities, with the most common being: hypertension, cancer, and chronic obstructive pulmonary disease. Results showed that following the introduction of SEM guided targeted treatments, participants in the treatment group yielded a statistically significant reduction in mean SEM delta scores (MD: 0.49; 95% CI: 0.59, 0.39; P < .0001), and in the odds of developing a SEM PU (OR: 0.59, 95% CI: 0.24 to 1.00; P = .05). In the treatment group, none of the participants developed a visual PU, whereas, in the control group, 1.41% (n = 1/71) developed a visual PU. Based on all the results, the following is concluded, (1). There was a greater reduction in mean SEM delta scores among those cared for using SEM measurement and targeted PU prevention, versus those cared for using visual skin assessment and usual care, and (2). the mean SEM delta scores was statistically significantly lower at the study end for those who received targeted treatments based on abnormal SEM scores. More research is now needed in other and larger at-risk groups to further validate what was found in this study.

Variations in sacral oedema levels over continuous 60-degree head of bed elevation positioning in healthy adults: An observational study

BACKGROUND

Subepidermal moisture (SEM) scanning is a novel technology that measures changes in localised oedema. Accumulation of subepidermal oedema is associated with early tissue damage that may lead to a pressure injury.

AIM

The primary study objective was to observe the variations in sacral subepidermal oedema levels over a continuous period of 60-degree head of bed elevation positioning.

METHODS

Healthy adult participants were recruited in this prospective observational study. Participants were positioned at 60-degree head of bed elevation for 120 min and sacral SEM measurements were collected at baseline and in 20 min increments.

RESULTS

A total of 20 participants with a mean age of 39.3 years (SD = 14.7) were recruited. The mean SEM delta value increased 6.3% from 0.46 SEM delta at baseline to 0.49 SEM delta after 120 min, however these differences are not statistically significant (p = .21). There were also no significant findings between SEM delta variations and demographic factors.

CONCLUSION

In a sample of healthy individuals, 120 min of continuous loading with a 60-degree head of bed elevation did not lead to a significant change in sacral subepidermal oedema levels. Further research on the response of healthy adult tissue under external forces associated with different angles of head of bed positioning may further contribute to our understanding pressure injury prevention.

Electronic Alert Signal for Early Detection of Tissue Injuries in Patients: An Innovative Pressure Sensor Mattress

Monitoring the early stage of developing tissue injuries requires intact skin for surface detection of cell damage. However, electronic alert signal for early detection is limited due to the lack of accurate pressure sensors for lightly pigmented skin injuries in patients. We developed an innovative pressure sensor mattress that produces an electronic alert signal for the early detection of tissue injuries. The electronic alert signal is developed using a web and mobile application for pressure sensor mattress reporting. The mattress is based on body distributions with reference points, temperature, and a humidity sensor to detect lightly pigmented skin injuries. Early detection of the pressure sensor is linked to an electronic alert signal at 32 mm Hg, a temperature of 37 °C, a relative humidity of 33.5%, a response time of 10 s, a loading time of 30 g, a density area of 1 mA, and a resistance of 7.05 MPa (54 N) at 0.87 m³/min. The development of the innovative pressure sensor mattress using an electronic alert signal is in line with its enhanced pressure detection, temperature, and humidity sensors.

Effect of Heat Shock Preconditioning on Pressure Injury Prevention via Hsp27 Upregulation in Rat Models

Pressure injury (PI) prevention is a huge industry and involves various interventions. Temperature and moisture are important factors for wound healing; however, the active mechanism by which “moist heat” affects PI prevention has not yet been clarified. Thus, we explored the protective and therapeutic effects of hydrotherapy on PI based on the preconditioning (PC) principle, which might be useful for clinical practice. This study aimed to investigate the preventive mechanisms of heat shock preconditioning on PIs in rat models. The experiment was performed in the basic medical laboratory of Nagano College of Nursing in Japan. Ten rats were divided into two groups, with five rats in each group. Rats in the control group were not bathed. Rats in the preconditioning group (PC group) were bathed with hot tap-water. Bathing was conducted thrice a week. After bathing for 4 weeks, the PI model was constructed on the rats’ dorsal skin. The skin temperature, skin moisture, and area of ulcers were compared between the two groups. In vitro, we investigated the expression of heat shock protein 27 (Hsp27) in 6, 12, and 24 h after the PI model was constructed through Western blot analysis. Ulcers occurred in the control group 24 h after the PI model constructed, wheras the PC group exhibited ulcers after 36 h. The ulcer area was larger in the control group than that in the PC group after 24 h (all p < 0.05). The temperatures of PI wounds in the control group decreased and were lower than those in the PC group after 1, 6, 12, 36, and 48 h (all p < 0.05). However, the skin moisture levels of PI wounds increased in the control group and were higher than those in the PC group at the same time (all p < 0.05). Using Western blot analysis, hydrotherapy preconditioning showed the potential to increase Hsp27 expression after pressure was released (p < 0.05). We determine that heat shock preconditioning had a preventive effect on PIs in rat models, a result that may be associated with their actions in the upregulation of Hsp27.

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

OBJECTIVE

The aim was to assess evidence related to the measuring of subepidermal moisture (SEM) to detect early, nonvisible development of pressure ulcers (PUs).

METHOD

Using systematic review methodology, all quantitative animal and human research studies written in English were considered. In January 2021, PubMed, CINAHL, SCOPUS, Cochrane and EMBASE databases were searched. The primary outcome of interest was the validity of SEM measurement to detect early PU development. The secondary outcome was time to PU detection, sensitivity and specificity of SEM measurement, and the impact of SEM measurements on PU prevention. Data analysis was undertaken using RevMan and narrative synthesis.

RESULTS

A total of 17 articles met the inclusion criteria. In all studies, a consistent abnormal deviation in SEM measurements corresponded with evidence of visual PU development. Time to PU development, explored in four studies, showed earlier detection of PU development using SEM measurement. RevMan analysis identified the mean difference in time to PU development (SEM measurement versus visual skin assessment, VSA) was 4.61 days (95% confidence interval: 3.94-5.28; p=0.0001) in favour of SEM measurements. The sensitivity of SEM measurements was reported in four studies, and scores varied from 48.3% to 100.0%. Specificity was also reported in four studies and scores ranged from 24.4% to 83.0%. The impact of the detection of abnormal SEM measurements on PU prevention was explored by one study. Results showed a 93% decrease in PU rates when staff acted on the results of the SEM readings.

CONCLUSION

The findings of this review identified that SEM measurement detects PU development earlier than VSA. Furthermore, when staff responded to abnormal SEM measurements, prevention strategies were enhanced, with a subsequent reduction in visible PU development. SEM measurement may therefore be a useful addition to PU prevention strategies.

DECLARATION OF INTEREST

The School of Nursing & Midwifery, RCSI has a research agreement with Bruin Biometrics. Funding for the study was through an Irish Research Council PhD Enterprise Partnership Scheme with Bruin Biometrics. The authors have no other conflicts of interest.

Oedema as a predictor of the incidence of new pressure injuries in adults in any care setting: A systematic review and meta-analysis

BACKGROUND

Oedema measurement, also termed sub-epidermal moisture measurement is recommended as an adjunct pressure injury prevention intervention in international guidelines because it indicates early tissue damage.

OBJECTIVE

To determine the prognostic value of oedema measurement in predicting future pressure injury in adults in any care setting.

DESIGN

Systematic review and meta-analysis.

SETTING

Participants were recruited from nursing homes or aged care facilities, hospitals, or post-acute facilities.

PARTICIPANTS

Adults.

METHODS

A modified 2-week systematic review was undertaken. Study designs included cohort (prospective and retrospective), case-control, case series if relevant comparisons were reported, randomised controlled trials if the association between oedema measurement and pressure injury was reported, and registry data. Databases searched included: Medical Literature Analysis and Retrieval System Online, The Cumulative Index to Nursing and Allied Health Literature, Excerpta Medica and the Cochrane Library from inception to 13 July 2021 with no language restrictions. Screening, data extraction using Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies - Prognostic Factors (CHARMS-PF) and quality assessment using Quality in Prognostic Factor Studies (QUIPS) were undertaken independently by ≥2 authors and adjudicated by another if required. Meta-analyses and meta-regression were undertaken. The certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

RESULTS

Six studies (n = 483 total) were included. Two studies were set in nursing homes and four in either hospitals or post-acute facilities. Fives studies were prospective cohorts, and one was a randomised control trial. Two studies were assessed as low risk and four studies as moderate risk of bias. The pooled risk ratio in four studies (n = 388) for the relationship between oedema and pressure injury cumulative incidence was 18.87 (95% CI 2.13-38.29) and for time to pressure injury was 4.08 days (95% CI 1.64-6.52). Using GRADE, the certainty of the body of evidence was low for all outcomes. Meta-regression indicated that age, gender, and sample size were poor predictors for the association between oedema and pressure injury.

CONCLUSIONS

Measuring oedema as a predictor for pressure injury development is showing promise but a stronger body of evidence that takes into consideration other prognostic factors is needed to better understand its benefit.

REGISTRATION

PROSPERO CRD42021267834.

TWEETABLE ABSTRACT

Measuring oedema is a promising strategy to prevent pressure injuries but the certainty of evidence for this claim is low.

A machine learning algorithm for early detection of heel deep tissue injuries based on a daily history of sub-epidermal moisture measurements

Sub‐epidermal moisture is an established biophysical marker of pressure ulcer formation based on biocapacitance changes in affected soft tissues, which has been shown to facilitate early detection of these injuries. Artificial intelligence shows great promise in wound prevention and care, including in automated analyses of quantitative measures of tissue health such as sub‐epidermal moisture readings acquired over time for effective, patient‐specific, and anatomical‐site‐specific pressure ulcer prophylaxis. Here, we developed a novel machine learning algorithm for early detection of heel deep tissue injuries, which was trained using a database comprising six consecutive daily sub‐epidermal moisture measurements recorded from 173 patients in acute and post‐acute care settings. This algorithm was able to achieve strong predictive power in forecasting heel deep tissue injury events the next day, with sensitivity and specificity of 77% and 80%, respectively, revealing the clinical potential of artificial intelligence‐powered technology for hospital‐acquired pressure ulcer prevention. The current work forms the scientific basis for clinical implementation of machine learning algorithms that provide effective, early, and anatomy‐specific preventive interventions to minimise the occurrence of hospital‐acquired pressure ulcers based on routine tissue health status measurements.

Repositioning Practice of Bedridden Patients: An Evolutionary Concept Analysis

Introduction

Repositioning practice is an essential pressure ulcer prevention intervention that has emerged in the history of nursing. Numerous terms are employed to indicate its meaning, such as turning, positioning, or posturing. However, there is no available analysis that distinguishes these terms or analyzes repositioning practice attributes.

Objective

To analyze repositioning practice as a concept of bedridden patients in hospitals by combining methods from Foucault's archeology of knowledge and Rodger's concept analysis.

Concept Description

Repositioning practice passes through three eras: classical, modern, and research. The repositioning practice is “turn a bedridden patient in a harmonized way and ends with anchor and documentation.” The analysis concludes seven attributes for the repositioning practice: pre-turn, assessment, turn, harmonization, anchor, documentation, and time. The analysis assumes bedridden patients, and assigned nurses on duty are the antecedents. Moreover, the main consequence is pressure ulcer prevention, while patient safety and quality of care are the secondary consequences.

Discussion

Repositioning practice understanding has grown with time. Each era has added to or removed from nursing's understanding for repositioning practice until it appears as it now. The current analysis expects further development in repositioning practice understanding and applications.

Conclusion

Repositioning practice is an important nursing intervention and has shown a dynamic movement over history. It is expected that this dynamic will continue in the future.

Developing Algorithm Based on Activity and Mobility for Pressure Ulcer Risk Among Older Adult Residents: Implications for Evidence-Based Practice

BACKGROUND

A pressure ulcer (PU) is a localized injury to the skin or underlying tissue usually over a bony prominence. The prevention PU per patient per day is costly; therefore, the detection of a PU at its earliest stage is imperative to afford timely interventions. Currently, there are very few clinically useful tools to assist with early PU detection and prevention.

AIM

There were two primary aims of this study: (1) to investigate the relationship between activity, mobility, and PU development; and (2) to ascertain the next steps for delineating an algorithm based on activity and mobility for detecting PU risk among older adult residents in long-term care.

METHOD

This quantitative, prospective, descriptive, non-experimental study was conducted between July 2019 and March 2020 among 53 older adult residents who were followed for 4 consecutive days. Participants' Braden score, Elderly Mobility Scale (EMS) score, Movement Level, and 6-item Cognitive Impairment Test score were assessed. Further, the sacrum and heels were assessed daily using a non-invasive subepidermal moisture (SEM) scanner and visual skin assessment (VSA). SEM values > 0.5 were considered as indicative of the presence of an SEM-PU.

RESULTS

The incidence rate of VSA-PU was 15.1% (N = 8). There was an incidence of 87.5% (N = 42) of SEM-PU damage. According to the Braden subscale, Mobility Braden, most of the participants (62.2%, N = 33) were assessed as having no limitations/slightly limited mobility, while the EMS indicated that most of the participants (67.9%, N = 36) were classed in an independent category. From the 42 SEM-PUs observed, 62% (N = 26) occurred among the low movers, and 38% (N = 16) occurred among the high movers.

LINKING EVIDENCE TO ACTION

Using traditional methods for the assessment of movement does not provide insight into the protective nature of the movement. Given that both low- and high-moving patients can develop tissue damage, it is important to focus on the assessment of movement using more objective measures and algorithms, which enable real-time assessment of the protective nature of the movement. This would enable development of person-centered PU prevention strategies to reduce the burden of this significant healthcare problem.

Clinical profile of the SEM Scanner - Modernizing pressure injury care pathways using Sub-Epidermal Moisture (SEM) scanning

INTRODUCTION

Pressure injuries (PIs) are a global health concern. Current PI care standards, including skin tissue assessments (STA) and health care professional (HCP) clinical judgment, diagnose visibly manifested PIs on the skin's surface, i.e. after the damage has already occurred. However, objective assessment of early-stage, non-visible, pressure-induced tissue damage is clinically impossible within the current standard of care. The SEM Scanner is the first device authorized by the Food and Drug Administration (FDA) that addresses this unmet clinical need.

AREAS COVERED

This review describes the novel sub-epidermal moisture (SEM) scanning technology of the device and summarizes the clinical safety and efficacy data that support the use of the scanner in routine PI care practice.

EXPERT OPINION

The clinical strategy for developing the SEM Scanner is noteworthy. SEM technology using anatomy-specific data enables HCPs to provide early PI prevention interventions before visible signs of tissue damage develop while the damage is still reversible. When adopted into routine practice, the device identifies an increased risk of developing PIs 5 days (median) earlier than STA. FDA clearance was based on bench studies and data from three foundational trials that demonstrate the diagnostic accuracy of the device algorithm significantly exceeding clinical judgment (p < 0.001).

Evaluating the sensitivity, specificity and clinical utility of algorithms of spatial variation in sub-epidermal moisture (SEM) for the diagnosis of deep and early-stage pressure-induced tissue damage

BACKGROUND

Sub-epidermal moisture (SEM) is a measurable biomarker detecting early pressure damage in order to objectively support current 'gold standard' skin tissue assessments (STA) for the detection of deep and early-stage pressure-induced injuries or ulcers (PI/PUs).

OBJECTIVE

A multi-site, dual arm, cross sectional, retrospective study was conducted to evaluate the sensitivity, specificity and clinical utility of spatial variation in SEM readings between healthy and damaged skin tissue.

METHOD

The study enrolled 175 subjects: 125 with confirmed PI/PUs or suspected deep tissue injury (sDTI), and 50 confirmed healthy subjects. Expert principal investigators and PI/PU healthcare practitioners (HCPs) evaluating all subjects were trained in SEM measurements but blinded to clinical interpretation of SEM readings. Sequential and spatial SEM readings of the sacrum and heels, subjects' demographic data, STAs, risk assessment tool scores (RATS), pain assessment and potential confounders were recorded. Independent statistical analyses were performed.

RESULTS

Mean spatial SEM measures within subjects with healthy tissue and within subjects with damaged tissue were statistically similar. Mean spatial SEM measures within anatomies of subjects with damaged tissue were significantly different (p<0.05). There was no significant difference between spatial readings in healthy subjects. Algorithms computing a range of SEM delta thresholds indicated a sensitivity of 82-87% and a specificity of 51-88% at an SEM delta ≥0.6. Receiver operating characteristic (ROC) curves computed areas under the curve (AUC) of 0.7809-0.9181 (95% CI: 0.7221-0.8817, 0.8397-0.9545, p<0.0001) exceeding clinical judgement.

CONCLUSION

These SEM data augment clinical decision-making for developing intact skin PI/PUs including sDTIs and Stage I PI/PUs. Informing HCPs of this subclinical, non-visible skin and tissue damage and providing opportunities for alternative PI/PU care pathways is an exciting prospect.

Clinical impact of a sub-epidermal moisture scanner: what is the real-world use?

OBJECTIVE

The presence of sub-epidermal moisture (SEM) over a bony prominence is indicative of incipient pressure ulcer (pressure injury/decubitus/bedsore) (PU). Early identification of patients at increased risk of PU can prompt interventions that reduce the incidence and severity of hospital (or community)-acquired PUs (HAPUs). This study evaluated the clinical utility of a SEM Scanner device in HAPU management.

METHOD

The study used a pragmatic 'real-world' approach. HAPU data before and during SEM Scanner use were obtained through routine audit. Patients had regular visual and daily SEM Scanner skin assessments over the sacrum and heels. Nursing care otherwise followed standard of care according to the established protocols of individual participating sites. HAPU incidence rates were determined and feedback gathered from health professionals on how the device influenced HAPU-related clinical decision-making.

RESULTS

There were 15 participating sites: 13 acute care, one palliative care and one community care setting. The sample size was 1478 patients. All sites reported a substantial reduction in mean HAPU incidence: 87.2% in acute care settings; 46.7% in the palliative care setting and 26.7% in the community care setting. A 100% incidence reduction was reported in 10 (66.7%) sites. In the palliative care setting, SEM Scanner results changed HAPU-related clinical decision-making for 40% of patients scanned. The community care site demonstrated a 82% change in clinical decision-making.

CONCLUSION

In this study, SEM analysis fitted seamlessly into routine skin assessment and enabled early identification of increased risk of tissue damage, with clinically important reductions in the incidence of HAPU across all participating sites.

Critical biomechanical and clinical insights concerning tissue protection when positioning patients in the operating room: A scoping review

An optimal position of the patient during operation may require a compromise between the best position for surgical access and the position a patient and his or her tissues can tolerate without sustaining injury. This scoping review analysed the existing, contemporary evidence regarding surgical positioning-related tissue damage risks, from both biomechanical and clinical perspectives, focusing on the challenges in preventing tissue damage in the constraining operating room environment, which does not allow repositioning and limits the use of dynamic or thick and soft support surfaces. Deep and multidisciplinary aetiological understanding is required for effective prevention of intraoperatively acquired tissue damage, primarily including pressure ulcers (injuries) and neural injuries. Lack of such understanding typically leads to misconceptions and increased risk to patients. This article therefore provides a comprehensive aetiological description concerning the types of potential tissue damage, vulnerable anatomical locations, the risk factors specific to the operative setting (eg, the effects of anaesthetics and instruments), the complex interactions between the tissue damage risk and the pathophysiology of the surgery itself (eg, the inflammatory response to the surgical incisions), risk assessments for surgical patients and their limitations, and available (including emerging) technologies for positioning. The present multidisciplinary and integrated approach, which holistically joins the bioengineering and clinical perspectives, is unique to this work and has not been taken before. Close collaboration between bioengineers and clinicians, such as demonstrated here, is required to revisit the design of operating tables, support surfaces for surgery, surgical instruments for patient stabilisation, and for surgical access. Each type of equipment and its combined use should be evaluated and improved where needed with regard to the two major threats to tissue health in the operative setting: pressure ulcers and neural damage.

The subepidermal moisture scanner: the technology explained

The objective of this article is to explain the biophysical principles underlying the design of the subepidermal moisture (SEM) scanner, commercially known as the 'SEM scanner'. We also describe the mode of operation of the SEM scanner in monitoring tissue health and detecting subtle abnormal changes in tissue physiology in patients and anatomical sites at a risk of a pressure ulcer (PU: also known as a pressure injury). The technology of the SEM scanner was approved last year for sales in the US by the Food and Drug Administration (FDA). The SEM scanner detects changes in fluid contents of human skin and subdermal tissues, to a tissue depth of several millimetres, by measuring 'capacitance', an electrical property of the locally examined tissue site to store electric charge. The capacitance of tissues, called 'biocapacitance', is strongly affected by the amount of fluid (water) in the tissue. When the first cells die in a forming PU, inflammatory signalling causes the permeability of blood vessel walls to increase and oedema to develop. Simply, the scanner detects the early appearance of oedema, which is called 'micro-oedema.' Calculation of a 'SEM-delta' value, which compares biocapacitance measurements, acquired across several tissue sites, some of which are healthy and others where the PU may evolve, eliminates potential effects of systemic changes in tissue fluid contents and provides a consistent quantitative measure of the tissue health conditions at the monitored anatomical site. Here, we describe SEM scanner technology, how it operates and has been laboratory tested (in computer simulations, in silico) before commercial launch. We explain why targeting the physical biomarker of oedema leads to the documented success of the SEM scanner in the multiple published clinical trials, proving its ability to early detect PUs that form under intact skin.

The subepidermal moisture scanner: the technology explained

The objective of this article is to explain the biophysical principles underlying the design of the subepidermal moisture (SEM) scanner, commercially known as the ‘SEM scanner’. We also describe the mode of operation of the SEM scanner in monitoring tissue health and detecting subtle abnormal changes in tissue physiology in patients and anatomical sites at a risk of a pressure ulcer (PU: also known as a pressure injury). The technology of the SEM scanner was approved last year for sales in the US by the Food and Drug Administration (FDA). The SEM scanner detects changes in fluid contents of human skin and subdermal tissues, to a tissue depth of several millimetres, by measuring ‘capacitance’, an electrical property of the locally examined tissue site to store electric charge. The capacitance of tissues, called ‘biocapacitance’, is strongly affected by the amount of fluid (water) in the tissue. When the first cells die in a forming PU, inflammatory signalling causes the permeability of blood vessel walls to increase and oedema to develop. Simply, the scanner detects the early appearance of oedema, which is called ‘micro-oedema.’ Calculation of a ‘SEM-delta’ value, which compares biocapacitance measurements, acquired across several tissue sites, some of which are healthy and others where the PU may evolve, eliminates potential effects of systemic changes in tissue fluid contents and provides a consistent quantitative measure of the tissue health conditions at the monitored anatomical site. Here, we describe SEM scanner technology, how it operates and has been laboratory tested (in computer simulations, in silico) before commercial launch. We explain why targeting the physical biomarker of oedema leads to the documented success of the SEM scanner in the multiple published clinical trials, proving its ability to early detect PUs that form under intact skin.

Phantom testing of the sensitivity and precision of a sub-epidermal moisture scanner

The majority of pressure ulcers (PUs) including deep tissue injuries (DTIs) are preventable, and even reversible if detected in their early phase. One of the greatest barriers in PU prevention is that clinicians traditionally depended on subjective and qualitative techniques, particularly routine visual skin assessments that would only document existing, macroscopic PUs/DTIs, rather than preventing them or detecting them at their microscopic phase. At the early phase of cell damage, when a forming PU is still microscopic, there is a local increase in extracellular fluid contents within affected tissues, which is called sub-epidermal moisture (SEM). This new understanding has led to an emerging technology, a SEM Scanner (BBI LLC, Bruin Biometrics) that has been designed to effectively examine the health status of tissues, by measuring local changes in the biophysical SEM marker. In the present work, the SEM Scanner was tested under controlled laboratory conditions to experimentally determine its sensitivity and precision in identifying small (1 mL) water content changes in phantoms of the human heel and skull/face, which simulated common PU development scenarios. In both phantom configurations, the locally increased water contents resulted in consistent, statistically significant elevated SEM readings, which confirms that the SEM Scanner is able to detect fluid content changes that are as small as 1 mL. In agreement with a simplified theoretical (mathematical) SEM model, which was also developed here, changes in water contents had a consistent trend of effect on SEM delta values, which increased with each 1 mL increment in intra-tissue-substitute water contents.