The Role of Shear Stress and Shear Strain in Pressure Injury Development.

ABSTRACT: Although other patient safety indicators have seen a decline, pressure injury (PI) incidence has continued to rise. In this article, the authors discuss the role of shear stress and shear strain in PI development and describe how accurate assessment and management can reduce PI risk. They provide explanations of shear stress, shear strain, friction, and tissue deformation to support a better clinical understanding of how damaging these forces are for soft tissue. Clinicians must carefully assess each patient's risk factors regarding shear forces within the contexts of activity and mobility. The authors also provide a toolbox of mitigation strategies, including support surface selection, selection of materials that contact the individual, management of immobility using positioning techniques, and the use of safe patient handling techniques. With a clear understanding of how shear forces affect PI risk and mitigation strategies, clinicians will more accurately assess PI risk and improve PI prevention care plans, ultimately reducing PI incidence to become more aligned with other patient safety indicators.

Best-practices for preventing skin injury beneath personal protective equipment during the COVID-19 pandemic: A position paper from the National Pressure Injury Advisory Panel.

COVID-19 has infected millions of patients and impacted healthcare workers worldwide. Personal Protective Equipment (PPE) is a key component of protecting frontline clinicians against infection. The benefits of PPE far outweigh the risks, nonetheless, many clinicians are exhibiting skin injury caused by PPE worn incorrectly. These skin injuries, ranging from lesions to open wounds are concerning because they increase the susceptibility of viral infection and transmission to other individuals. Early into the COVID-19 pandemic (April 2020), the U. S. National Pressure Injury Advisory Panel (NPIAP) developed a series of position statements to improve wear-ability of PPE and protect healthcare professionals and their patients as safe from harm as possible under the circumstances. The NPIAP positions, which were formed by conducting a systematic review of what was known at the time, include: (a) Prepare skin before and after wearing PPE with skin sealants, barrier creams and moisturisers; (b) Frequent PPE offloading to relieve pressure and shear applied to skin; (c) treat visible skin injuries immediately caused by PPE to minimise future infection; (d) non-porous dressings may provide additional skin protection, but lack evidence; (e) health systems should take care to educate clinicians about placement and personal hygiene related to handling PPE. Throughout all of these practices, handwashing remains a top priority to handle PPE. These NPIAP positions provided early guidance to reduce the risk of skin injury caused by PPE based on available research regarding PPE injuries, a cautious application of evidence-based recommendations on prevention of device-related pressure injuries in patients and the expert opinion of the NPIAP Board of Directors. Clinicians who adhere to these recommendations reduce the prospects of skin damage and long-term effects (e.g. scarring). These simple steps to minimise the risk of skin injury and reduce the risk of coronavirus infection from PPE can help.

Effects of simulated aging on cushion performance measured using standardized laboratory test methods.

Standardized test methods providing wheelchair cushion performance characteristics can aid cushion design and selection. Assessment of the changes in performance that occur with aging provides additional information. Test methods published by the International Organization for Standardization were applied to a cohort of 21 cushions of varying design and construct to assess changes in performance due to simulated aging. Performance tests measured immersion, envelopment, stiffness, impact response, and pressure distribution properties. Means of test outcome metrics pre- and post-aging are presented, and changes in the metrics due to aging are analyzed using linear mixed models. Statistically significant changes were found for outcome measures for each performance test. The minimum aging method simulating 18-24 months use had a significant effect on cushion performance. Changes to loaded contour depth, envelopment, pressure mapping, hysteresis, horizontal stiffness, and 10% force deflection characterization test metrics indicated decreased cushion performance. The simulated aging method resulted in cushion stiffening and reduced immersion, pressure distribution, and stability performance. Together, these changes may increase a user's risk for pressure injuries.

Our contemporary understanding of the aetiology of pressure ulcers/pressure injuries.

In 2019, the third and updated edition of the Clinical Practice Guideline (CPG) on Prevention and Treatment of Pressure Ulcers/Injuries has been published. In addition to this most up-to-date evidence-based guidance for clinicians, related topics such as pressure ulcers (PUs)/pressure injuries (PIs) aetiology, classification, and future research needs were considered by the teams of experts. To elaborate on these topics, this is the third paper of a series of the CPG articles, which summarises the latest understanding of the aetiology of PUs/PIs with a special focus on the effects of soft tissue deformation. Sustained deformations of soft tissues cause initial cell death and tissue damage that ultimately may result in the formation of PUs/PIs. High tissue deformations result in cell damage on a microscopic level within just a few minutes, although it may take hours of sustained loading for the damage to become clinically visible. Superficial skin damage seems to be primarily caused by excessive shear strain/stress exposures, deeper PUs/PIs predominantly result from high pressures in combination with shear at the surface over bony prominences, or under stiff medical devices. Therefore, primary PU/PI prevention should aim for minimising deformations by either reducing the peak strain/stress values in tissues or decreasing the exposure time.

Effect of CHRFAM7A Δ2bp gene variant on secondary inflammation after spinal cord injury.

The α7 neuronal nicotinic acetylcholine receptors (α7nAChRs) are essential for anti-inflammatory responses. The human-specific CHRFAM7A gene and its 2bp deletion polymorphism (Δ2bp variant) encodes a structurally-deficient α7nAChRs that may impact the anti-inflammatory function. We studied 45 spinal cord injury (SCI) patients for up to six weeks post SCI to investigate the role of the Δ2bp variant on multiple circulating inflammatory mediators and two outcome measures (neuropathic pain and risk of pressure ulcers). The patient's SCI were classified as either severe or mild. Missing values were imputed. Overall genetic effect was conducted with independent sample t-test and corrected with false discovery rate (FDR). Univariate analysis and regression analysis were applied to evaluate the Δ2bp effects on temporal variation of inflammatory mediators post SCI and their interaction with outcome measures. In severe SCI, the Δ2bp carriers showed higher levels of circulating inflammatory mediators than the Δ2bp non-carriers in TNF-α (FDR = 9.6x10-4), IFN-γ (FDR = 1.3x10-3), IL-13 (FDR = 1.6x10-3), CCL11 (FDR = 2.1x10-3), IL-12p70 (FDR = 2.2x10-3), IL-8 (FDR = 2.2x10-3), CXCL10 (FDR = 3.1x10-3), CCL4 (FDR = 5.7x10-3), IL-12p40 (FDR = 7.1x10-3), IL-1b (FDR = 0.014), IL-15 (FDR = 0.024), and IL-2 (FDR = 0.037). IL-8 and CCL2 were negatively associated with days post injury (DPI) for the Δ2bp carriers (P = 2x10-7 and P = 2x10-8, respectively) and IL-5 was positively associated with DPI for the Δ2bp non-carriers (P = 0.015). Neuropathic pain was marginally positively associated with IL-13 for the Δ2bp carriers (P = 0.056). In mild SCI, the Δ2bp carriers had lower circulating levels of IL-15 (FDR = 0.04) than the Δ2bp non-carriers. Temporal variation of inflammatory mediators post SCI was not associated with the Δ2bp variant. For the mild SCI Δ2bp carriers, risk of pressure ulcers was positively associated with circulating levels of IFN-γ, CXCL10, and CCL4 and negatively associated with circulating levels of IL-12p70. These findings support an important role for the human-specific CHRFAM7A Δ2bp gene variant in modifying anti-inflammatory function of α7nAChRs following SCI.

Development of a Wheelchair Repair Registry.

OBJECTIVE: To describe the development of a wheelchair repair registry from large datasets to attain an understanding of wheelchair failures and service repairs. DESIGN: Guidelines for registry development were applied and anchored around Labor-Tracker, a web-based information management system for wheelchair suppliers to manage and track wheelchair repairs. The registry was designed using online analytical processing, allowing for rapid data queries from multiple dimensions that enable complex data analysis and discovery. SETTING: The Wheelchair Repair Registry (WRR) was developed through an industry and academic collaboration whereby repair data were collected in the field, entered into the Labor-Tracker system, deidentified, and then transferred to the registry and made available for analyses. PARTICIPANTS: Wheelchair supplier service technicians reported data from repair services provided to individuals who use power wheelchairs, manual wheelchairs, and scooters. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Wheelchair failure and repair data, including variables related to scheduling, equipment information (eg, manufacturer, model, serial number, purchase date), labor, parts, and reasons for repairs. RESULTS: The WRR was developed to analyze wheelchair repairs and failures from the Labor-Tracker system. Currently, the registry has more than 60,000 repairs conducted on more than 5000 wheelchair devices from 25 manufacturers. The devices include 60% power wheelchairs, 35% manual wheelchairs, and 5% scooters. CONCLUSIONS: The WWR creates opportunities to apply large-data analytical methodologies that will serve to inform quality standards, practice, equipment selection, preventative maintenance routines, product design, and policy.

A comparison of air-cell and gel surgical table pads and an evaluation of the influence of pressure distribution and other factors on pressure injury prevention.

Guidelines for pressure injury prevention consider the use of pressure-redistributing pads to prevent tissue deformation. However, limited research exists to assess the pressure distribution provided by the operating tables and the effectiveness of pressure-redistributing pads in preventing pressure injuries. In this study, we compared the pressure distribution properties of two surgical table pads and identified parameters influencing pressure injury outcomes after a lengthy surgical procedure. Twenty-seven patients undergoing left ventricular assist device implantation surgery participated in the study. Participants were randomly assigned to use either an air cell-based pad or a gel pad. Interface pressure was recorded during the surgery. We analyzed the effect of surgical table pad type, interface pressure distribution and pressure injury outcomes and analyzed what characteristics of the patients and the interface pressure are most influential for the development of pressure injuries. Comparing the interface pressure parameters between the air-cell group and the gel group, only the peak pressure index x time was significantly different (p < 0.05). We used univariate logistic regression analysis to identify significant predictors for the pressure injury outcome. The support surface was not significant. And, among patient characteristics, only age and BMI were significant (p ≤ 0.05). Among the interface pressure parameters, pressure density maxima, peak pressure index x time, and coefficient of variation were significant for pressure injury outcome (p ≤ 0.05). Peak pressure index, average pressure, and the surgery length were not statistically significant for pressure injury outcomes.

Exploring the first pressure injury and characteristics of subsequent pressure injury accrual following spinal cord injury.

Context/Objective: Clinicians have guidance on prevention and treatment of pressure injuries, but little is known regarding characteristics of patients who develop additional pressure injuries. Thus, our objective was to explore the first pressure injury and characteristics of individuals who develop subsequent pressure injuries during acute care and inpatient rehabilitation following spinal cord injury.Design: Secondary analysis of longitudinal data from a cohort of adults following initial traumatic spinal cord injury.Setting: Urban acute care hospital and inpatient rehabilitation facilities.Participants: A convenience sample of adults (n = 38) who developed at least one pressure injury during acute care and inpatient rehabilitation.Interventions: Not applicable.Outcome Measures: The primary outcomes were number of additional pressure injuries and stage of care during which they occurred, prior to community discharge.Results: A covariate-adjusted model revealed that participants with ASIA D injury had a 67% decrease in the rate of additional pressure injury incidence compared to participants with ASIA A injury (Rate Ratio = .33, 95% CI [0.13, 0.88]). The severity of the first pressure injury had no significant association with subsequent pressure injury incidence (P = .10).Conclusion: These findings indicated that individuals with greater sensory and motor loss had an increased risk of developing additional pressure injuries compared to individuals with less impairment. These results are meaningful for stakeholders interested in understanding factors associated with developing subsequent pressure injuries during the index rehabilitation stay and provide a foundation for future research in this area.

An exploratory study analyzing demographics and opinions of assistive technology professionals within the complex rehab technology industry.

This exploratory study investigated the demographics of Assistive Technology Professionals (ATPs) regarding their age, education, certifications, ethnicity, gender, veteran status, disability status, method of financial compensation, company type, and category. In addition, it analyzed opinions on the Complex Rehab Technology (CRT) industry regarding education level and licensure. An 18-question survey developed and disseminated by the University of Pittsburgh in collaboration with the National Coalition for Assistive & Rehab Technology (NCART) resulted in 252 responses from current ATPs in the Supplier/Manufacturing industry. The average age of respondents of 51.9 years showed to be above the national average workforce age of 42.2 years. Data were analyzed as a whole and by comparing answers for respondents below and above the average age. 92.4% of the respondents were Caucasian and 79.0% were male showing a need for diversity in the field. Forty-five percent of the younger age group had additional certifications compared to 30% of the older group. 79.8% of all respondents would recommend the ATP profession to someone looking for a career. Findings support the need to increase awareness of the ATP supplier/manufacturing profession to attract younger professionals including those from minority groups. Findings also support the need for additional training for the profession.

Implementing local cooling to increase skin tolerance to ischemia during normal seating in people with spinal cord injury.

The purpose of this study was to investigate the effectiveness of local cooling in reducing reactive hyperemia after ischemia at the ischial tuberosities for people with spinal cord injury (SCI) during normal seating. The degree of the reactive hyperemic response is indicative of the extent of cellular stress caused by the ischemia. We hypothesized that reactive hyperemic skin blood flow (SBF) responses will be lower when local cooling is implemented by the wheelchair seat cushion. This study used a repeated measures design, and each subject underwent two conditions: normal seating with temperature control 'on' (cooling) and 'off' (non-cooling) for 30 min. Twenty-three participants with traumatic SCI were recruited. SBF and skin temperature were collected before, during and after seating. SBF signals were processed with short-time Fourier analyses to examine the underlying vascular control mechanisms, including the following (corresponding frequency bands): metabolic (0.0095-0.02 Hz), neurogenic (0.02-0.05 Hz), and myogenic (0.05-0.15 Hz) spectral densities. Our results showed that with cooling, skin temperature decreased (range -0.4 ~ -3.1 °C, p = 0.002), and reactive hyperemia parameters (normalized peak SBF and perfusion area) were reduced (p = 0.02, p = 0.033, respectively). In addition, changes in normalized peak SBF (non-cooling - cooling) was moderately correlated with changes in normalized metabolic and neurogenic spectral densities. Our findings suggested that local cooling has a positive effect on reducing the cellular stress caused by ischemia during normal seating. Metabolic and neurogenic SBF control mechanisms may play a minor role. Further exploration of the effect of temperature control on pressure injury prevention is warranted.

Sacral skin blood flow response to alternating pressure operating room overlay.

Pressure injuries resulting from long surgeries may be caused by prolonged ischemia. Operating table surfaces with alternating pressure (AP) features may reduce the risk of ischemia-induced pressure injuries by providing periodic relief of blood flow occlusions. Prior research investigated alternating loading applied with a single isolated rigid indenter and demonstrated increased perfusion. This study quantified effects of an overlay with AP on sacral skin perfusion for individuals lying supine for 60-min while blood flow was monitored. The mean normalized sacral skin blood flow was found to be greater with the AP overlay over an operating table pad compared to the operating pad alone (pad with AP mean SBF = 1.45 ±â€¯1.16, pad without AP mean SBF = 1.03 ±â€¯0.46, p = 0.10). Peak and average interface pressure at the sacrum was significantly lower during the deflation cycle of the AP surface compared to the operating pad alone (P < 0.001), suggesting this periodic reduction resulted in higher mean blood flow. Post-hoc regression analysis showed participant body mass index was a significant predictor of the effectiveness of the AP overlay (p = 0.012). The results suggest risk for pressure injuries due to prolonged ischemia might be mitigated by the addition of an alternating pressure feature on operating table pads for lower BMI patients.

Association of a Functional Polymorphism in the CHRFAM7A Gene with Inflammatory Response Mediators and Neuropathic Pain after Spinal Cord Injury.

The alpha 7 nicotinic acetylcholine receptor, α7 nAChR, plays a central role in regulating inflammatory responses. Previous studies showed that pharmacological inhibitors of α7nAChR have a pro-inflammatory effect, increasing the circulating levels of cytokines such as tumor necrosis factor alpha (TNFα). This study focused on how genetic polymorphisms of the partially duplicated α7nAChR gene (CHRFAM7A), which is highly expressed in peripheral blood cells, contribute to functional outcome after spinal cord injury (SCI). In a cohort of 27 SCI patients and 25 emergency room consented controls (% F/M: 15/85, 24/76; mean ± SE age: 35 ± 1.38 and 35 ± 2.0 respectively), a panel of circulating cytokines, noradrenergic metabolite (normetanephrine [NMN]) levels, and clinical data were available within the first 7 days post-injury (DPI) up to 90 DPI, and were investigated in the acute/subacute (DPI 1-21) and intermediate (DPI 22-90) temporal periods. Cytokine and NMN plasma levels on different DPI were analyzed as a function of CHRFAM7A genotype. TNFα levels, as a representative of some elevated inflammatory mediators, were nearly threefold higher in individuals carrying the del-2bp variant of the CHRFAM7A gene compared with that in the no-deletion genotype (p = 0.001 analysis of variance [ANOVA]) 3 weeks DPI, and twofold higher than genotype-matched acute/subacute non-SCI injury controls within 7 days DPI. In contrast, NMN levels were initially unchanged, although after 3 weeks, NMN levels were significantly decreased in SCI individuals carrying the del-2bp variant compared with non-carriers (p = 0.011 ANOVA). Numerical pain scores over this same period post-injury were significantly elevated in SCI patients carrying the del-2bp variant relative to non-carriers (p = 0.001 ANOVA). Taken together, these data reveal that pro-inflammatory responses associated with CHRFAM7A gene variation may also be associated with differences in pain experience in patients following SCI, at least during the intermediate phase.

Detection and classification methodology for movements in the bed that supports continuous pressure injury risk assessment and repositioning compliance.

Pressure injuries are costly to the healthcare system and mostly preventable, yet incidence rates remain high. Recommendations for improved care and prevention of pressure injuries from the Joint Commission revolve around continuous monitoring of prevention protocols and prompts for the care team. The E-scale is a bed weight monitoring system with load cells placed under the legs of a bed. This study investigated the feasibility of the E-scale system for detecting and classifying movements in bed which are relevant for pressure injury risk assessment using a threshold-based detection algorithm and a K-nearest neighbor classification approach. The E-scale was able to detect and classify four types of movements (rolls, turns in place, extremity movements and assisted turns) with >94% accuracy. This analysis showed that the E-scale could be used to monitor movements in bed, which could be used to prompt the care team when interventions are needed and support research investigating the effectiveness of care plans.

Medical Rehabilitation: Guidelines to Advance the Field With High-Impact Clinical Trials.

The purpose of this Special Communication is to summarize guidelines and recommendations stemming from an expert panel convened by the National Institutes of Health, National Center for Medical Rehabilitation Research (NCMRR) for a workshop entitled The Future of Medical Rehabilitation Clinical Trials, held September 29-30, 2016, at the NCMRR offices in Bethesda, Maryland. The ultimate goal of both the workshop and this summary is to offer guidance on clinical trials design and operations to the medical rehabilitation research community, with the intent of maximizing the effect of future trials.

A Randomized Clinical Trial of Wheeled Mobility for Pressure Injury Prevention and Better Function.

OBJECTIVES: To evaluate the effectiveness of wheelchair assessment and configuration on pressure injury incidence, mobility, and functioning in a wheelchair. DESIGN: Randomized controlled trial with participants individually randomized into intervention and control groups. SETTING: Nursing home. PARTICIPANTS: Nursing home residents aged 60 and older who used wheelchairs and were at risk for pressure injuries (N=258). INTERVENTION: Treatment and evaluation, individually configured wheelchair and skin protection cushion; control and evaluation, facility-provided wheelchair and skin protection cushion. MEASUREMENTS: Pressure injury incidence, Nursing Home Life Space Diameter score, Functioning Every Day in a Wheelchair-Capacity (FEW-C) score, and Wheelchair Skills Test (WST) score. RESULTS: No differences in pressure injuries (p=.77) were found. Pelvic rotation (odds ratio (OR)=0.15, 95% confidence interval (CI)=0.03-0.70, p=.02) and Day 14 WST skill score (OR=0.74, 95% CI=0.60-0.91, p=.004) were significant predictors of pressure injuries. Significant differences were observed between groups in change in FEW-C independence scores between before randomization and endpoint (p=.03) and before randomization and 14 days (p=.04). CONCLUSION: Participants with individually configured wheelchairs improved more in the safe and effective use of their wheelchairs than residents with facility-provided wheelchairs. The outcomes indicated that nursing home residents functioned safely at a higher level in their wheelchairs if their devices were individually configured using a comprehensive wheelchair and seating assessment process. There was no difference in the incidence of pressure injuries between the two groups. TRIAL REGISTRATION: NCT01275313.

An MRI investigation of the effects of user anatomy and wheelchair cushion type on tissue deformation.

AIM OF THE STUDY: Tissue deformation is recognized as an important risk factor for pressure injuries. This study investigated the effects of anatomy and wheelchair cushion type on tissue deformation. MATERIALS AND METHODS: Direct 3-dimensional tissue deformation response was measured for six participants sitting on six different wheelchair cushions using MR imaging. Two participants had a traumatic spinal cord injury (SCI) within one year of the assessment, two sustained traumatic SCI at least 13 years prior, and two were without SCI. Tissue deformation was quantified using the difference in volume of tissue beneath the ischial tuberosity (IT) between unloaded and loaded (sitting) conditions. RESULTS: The participants with SCI tended to have less muscle tissue volume beneath their ITs while sitting compared to participants without SCI. Reductions in muscle and fat volumes in the loaded conditions varied depending on both cushion and participant. Higher interface pressures tended to be associated with lower unloaded tissue thicknesses. CONCLUSION: The study showed no single cushion type tested produced the lowest amount of tissue deformation across all participants. Individual anatomy and cushion type affect deformation response of tissue and related pressure injury risk.

How a diverse research ecosystem has generated new rehabilitation technologies: Review of NIDILRR's Rehabilitation Engineering Research Centers.

Over 50 million United States citizens (1 in 6 people in the US) have a developmental, acquired, or degenerative disability. The average US citizen can expect to live 20% of his or her life with a disability. Rehabilitation technologies play a major role in improving the quality of life for people with a disability, yet widespread and highly challenging needs remain. Within the US, a major effort aimed at the creation and evaluation of rehabilitation technology has been the Rehabilitation Engineering Research Centers (RERCs) sponsored by the National Institute on Disability, Independent Living, and Rehabilitation Research. As envisioned at their conception by a panel of the National Academy of Science in 1970, these centers were intended to take a "total approach to rehabilitation", combining medicine, engineering, and related science, to improve the quality of life of individuals with a disability. Here, we review the scope, achievements, and ongoing projects of an unbiased sample of 19 currently active or recently terminated RERCs. Specifically, for each center, we briefly explain the needs it targets, summarize key historical advances, identify emerging innovations, and consider future directions. Our assessment from this review is that the RERC program indeed involves a multidisciplinary approach, with 36 professional fields involved, although 70% of research and development staff are in engineering fields, 23% in clinical fields, and only 7% in basic science fields; significantly, 11% of the professional staff have a disability related to their research. We observe that the RERC program has substantially diversified the scope of its work since the 1970's, addressing more types of disabilities using more technologies, and, in particular, often now focusing on information technologies. RERC work also now often views users as integrated into an interdependent society through technologies that both people with and without disabilities co-use (such as the internet, wireless communication, and architecture). In addition, RERC research has evolved to view users as able at improving outcomes through learning, exercise, and plasticity (rather than being static), which can be optimally timed. We provide examples of rehabilitation technology innovation produced by the RERCs that illustrate this increasingly diversifying scope and evolving perspective. We conclude by discussing growth opportunities and possible future directions of the RERC program.