Improving the effect of shear on skin viability with wound dressings

Modeling Wound Chronicity In Vivo: The Translational Challenge to Capture the Complexity of Chronic Wounds

In an aging society with common lifestyle-associated health issues such as obesity and diabetes, chronic wounds pose a frequent challenge that physicians face in everyday clinical practice. Therefore, nonhealing wounds have attracted much scientific attention. Several in vitro and in vivo models have been introduced to deepen our understanding of chronic wound pathogenesis and amplify therapeutic strategies. Understanding how wounds become chronic will provide insights to reverse or avoid chronicity. Although choosing a suitable model is of utmost importance to receive valuable outcomes, an ideal in vivo model capturing the complexity of chronic wounds is still missing and remains a translational challenge. This review discusses the most relevant mammalian models for wound healing studies and provides guidance on how to implement the hallmarks of chronic wounds. It highlights the benefits and pitfalls of established models and maps out future avenues for research.

Effects of loading and prophylactic dressings on the sacral and heel skin: An exploratory cross-over trial

Pressure ulcers/injuries are caused by sustained loading and deformation of skin and underlying soft tissues. Prophylactic dressings are recommended as an adjunct to other preventive measures such as repositioning and offloading. The aim of this study was to investigate the effects of prophylactic soft silicone multi‐layered foam dressings on the skin structure and function of the two most common pressure areas, sacrum and heel, with and without loading. An exploratory randomised cross‐over trial using intra‐individual comparisons was conducted. Eight healthy volunteers (mean age 27.5 years) were assigned to three groups and either spent 2.5 hours on a standard hospital mattress lying in supine position with and without dressings or spent 2.5 hours with dressings applied but without loading. Skin temperature, stratum corneum, and epidermal hydration increased in all groups irrespective of wearing a dressing and/or loading. Mean roughness decreased at the heels. Reactive hyperaemia and the release of interleukin 1 alpha were associated with loading only. Results suggest that the occlusive effects of dressings are similar or only slightly greater than those observed with non‐loading or loading without dressings. Thus, a dressing does not cause additional irritation or skin changes during loading but it may reduce the inflammatory response.

The relationship between common risk factors and the pathology of pressure ulcer development: a systematic review

OBJECTIVE

The aim of this systematic review was to examine the associations and relationship between commonly cited risk factors and the pathology of pressure ulcer (PU) development.

METHOD

Using systematic review methodology, original research studies, prospective design and human studies written in English were included. The search was conducted in March 2018, using Ovid, Ovid EMBASE and CINAHL databases. Data were extracted using a pre-designed extraction tool and all included studies were quality appraised using the evidence-based librarianship critical appraisal.

RESULTS

A total of 382 records were identified, of which five met the inclusion criteria. The studies were conducted between 1994 and 2017. Most studies were conducted in hospital and geriatric wards. The mean sample size was 96±145.7 participants. Ischaemia, recovery of blood flow and pathological impact of pressure and shear was mainly found as the cited risk factor and PU aetiology.

CONCLUSION

This review systematically analysed five papers exploring the relationship between risk factors for PU development and aetiology. It identified many risk factors and underlying pathological mechanisms that interact in the development of PU including ischaemia, stress, recovery of blood flow, tissue hypoxia and the pathological impact of pressure and shear. There are several pathways in which these pathological mechanisms contribute to PU development and identifying these could establish potential ways of preventing or treating the development of PU for patients.

Painless local pressure application to test microvascular reactivity to ischemia

BACKGROUND

Forearm cutaneous blood flux (CBF) measurement with post-occlusive reactive hyperemia (PORH) is uncomfortable and may not be devoid of risks. We aimed to investigate post-compression reactive hyperemia (PCRH) with a custom-made indenter that was designed to be easily used routinely by inexperienced observers.

METHODS

Medical students evaluated PCRH with 1- to 4-min pressure applications of 16 to 34 kPa and PORH with 3-min forearm cuff occlusion using laser speckle contrast imaging in 15 healthy volunteers. Participants were asked to quantify their discomfort with a visual analogue scale (VAS) of 10 cm. Total ischemia (ISCH) was quantified by the product of CBF during ischemia and ischemia duration (min). We subtracted the CBF changes in the skin from a reference ipsilateral (PCRH) or contralateral (PORH) non-stimulated area.

RESULTS

The average VAS was 1.0 for PCRH vs. 6.0 for PORH (p < 0.001). A strong linear relationship between ISCH and peak PCRH (r² = 0.915, p < 0.001) was noted. Peak PORH values (63.9 laser perfusion units (LPU)) were significantly lower than all values of the 3-min PCRH (72.6 LPU), including the one obtained with 16 kPa.

CONCLUSION

Inexperienced observers could test microvascular reactivity with PCRH without inducing the discomfort that is typically experienced with PORH. Further, PCRH elicits a higher peak response to ischemia compared with PORH. This extremely simple method could influence a broad spectrum of routine cutaneous microcirculation investigations, especially when a painful approach is particularly inadequate or if the patient is fragile.

CLINICAL TRIAL REGISTRATION

NCT02861924.

Midrange Braden Subscale Scores Are Associated With Increased Risk for Pressure Injury Development Among Critical Care Patients

PURPOSE

The purpose of the current study was to examine the relationship between pressure injury development and the Braden Scale for Pressure Sore Risk subscale scores in a surgical intensive care unit (ICU) population and to ascertain whether the risk represented by the subscale scores is different between older and younger patients.

DESIGN

Retrospective review of electronic medical records.

SUBJECTS AND SETTING

The sample comprised patients admitted to the ICU at an academic medical center in the Western United States (Utah) and Level 1 trauma center between January 1, 2008 and May 1, 2013. Analysis is based on data from 6377 patients.

METHODS

Retrospective chart review was used to determine Braden Scale total and subscale scores, age, and incidence of pressure injury development. We used survival analysis to determine the hazards of developing a pressure injury associated with each subscale of the Braden Scale, with the lowest-risk category as a reference. In addition, we used time-dependent Cox regression with natural cubic splines to model the interaction between age and Braden Scale scores and subscale scores in pressure injury risk.

RESULTS

Of the 6377 ICU patients, 214 (4%) developed a pressure injury (stages 2-4, deep tissue injury, or unstageable) and 516 (8%) developed a hospital-acquired pressure injury of any stage. With the exception of the friction and shear subscales, regardless of age, individuals with scores in the intermediate-risk levels had the highest likelihood of developing pressure injury.

CONCLUSION

The relationship between age, Braden Scale subscale scores, and pressure injury development varied among subscales. Maximal preventive efforts should be extended to include individuals with intermediate Braden Scale subscale scores, and age should be considered along with the subscale scores as a factor in care planning.

Clinical and biomechanical perspectives on pressure injury prevention research: The case of prophylactic dressings

In this perspective paper, we discuss clinical and biomechanical viewpoints on pressure injury (or pressure ulcer) prevention research. We have selected to focus on the case of prophylactic dressings for pressure injury prevention, and the background of the historical context of pressure injury research, as an exemplar to illuminate some of the good and not so good in current biomechanical and clinical research in the wound prevention and care arena. Investigators who are conducting medical or clinical research in academia, in medical settings or in industry to determine the efficacy of wound prevention and care products could benefit from applying some basic principles that are detailed in this paper, and that should leverage the research outcomes, thereby contributing to setting higher standards in the field.