Wound Bed Preparation 2021.

GENERAL PURPOSE: To present the 2021 update of the Wound Bed Preparation paradigm. TARGET AUDIENCE: This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care. LEARNING OBJECTIVES/OUTCOMES: After participating in this educational activity, the participant will: 1. Apply wound assessment strategies. 2. Identify patient concerns about wound care. 3. Select management options for healable, nonhealable, and maintenance wounds.

Wound Bed Preparation is a paradigm to optimize chronic wound treatment. This holistic approach examines the treatment of the cause and patient-centered concerns to determine if a wound is healable, a maintenance wound, or nonhealable (palliative). For healable wounds (with adequate blood supply and a cause that can be corrected), moisture balance is indicated along with active debridement and control of local infection or abnormal inflammation. In maintenance and nonhealable wounds, the emphasis changes to patient comfort, relieving pain, controlling odor, preventing infection by decreasing bacteria on the wound surface, conservative debridement of slough, and moisture management including exudate control. In this fourth revision, the authors have reformulated the model into 10 statements. This article will focus on the literature in the last 5 years or new interpretations of older literature. This process is designed to facilitate knowledge translation in the clinical setting and improve patient outcomes at a lower cost to the healthcare system.

Technological features of advanced skin protectants and an examination of the evidence base.

Products that provide a protective skin barrier play a vital role in defending the skin against the corrosive effect of bodily fluids, including wound exudate, urine, liquid faeces, stoma output and sweat. There are many products to choose from, which can be broadly categorised by ingredients. This article describes the differences in mechanisms of action between barrier products comprising petrolatum and/or zinc oxide, silicone film-forming polymers and cyanoacrylates, and compares the evidence on them. The literature indicates that all types of barrier product are clinically effective, with little comparative evidence indicating that any one ingredient is more efficacious than another, although film-forming polymers and cyanoacrylates have been found to be easier to apply and more cost-effective. However, laboratory evidence, albeit limited, indicates that a concentrated cyanoacrylate produced a more substantial and adherent layer on a porcine explant when compared with a diluted cyanoacrylate and was more effective at protecting skin from abrasion and repeated exposure to moisture than a film-forming polymer. Finally, a silicone-based cream containing micronutrients was found to significantly reduce the incidence of pressure ulceration when used as part of a comprehensive prevention strategy.

Effect of a surfactant-based gel on patient quality of life.

The characteristic clinical signs of chronic wounds, which remain in a state of prolonged inflammation, include increased production of devitalised tissue and exudate, pain and malodour. The presence of necrotic tissue, slough and copious exudate encourages microbial proliferation, potentially resulting in planktonic and/or biofilm infection. For patients, the consequences can include leakage of exudate, pain and reduced mobility, which can impair their ability to socialise and perform activities of daily living. This can severely reduce their quality of life and wellbeing. Concentrated surfactant-based gels (Plurogel and Plurogel SSD) are used in wound cleansing to help manage devitalised tissue. In vitro studies indicate they can sequester planktonic microbes and biofilm from the wound bed, although there is, limited clinical evidence to support this. A group of health professionals who have used this concentrated surfactant gel, in combination with standard care, in their clinical practice for several years recently met at a closed panel session. Here, they present case studies where topical application of these gels resulted in positive clinical outcomes in previously long-standing recalcitrant wounds. In all cases, the reduction in inflammation and bioburden alleviated symptoms that previously severely impaired health-related quality of life and wellbeing.

Tolerance of Biofilms to Antimicrobials and Significance to Antibiotic Resistance in Wounds.

A biofilm is a community of microorganisms that adhere to each other and to surfaces and secrete extracellular polymeric substances (EPS) encasing themselves in a matrix. Biofilms are a major healthcare concern, as they can form on medical devices leading to infection. Additionally, there is growing evidence to show their ability to form in chronic wounds, which leads to delayed wound healing and inflammation. Due to a number of reasons, such as formation of the EPS resulting in sub-inhibitory concentrations of antimicrobials reaching the bacterial cells, slow growth rate of bacterial cells rendering some antibiotics ineffective, and the presence of persister cells, biofilms show increased tolerance to many antimicrobials and antibiotics. Additionally, studies have started to emerge showing a link between resistance to antimicrobials and antibiotics. Cross-resistance can be attributed to a number of factors, for example, increased expression of multidrug efflux pumps that efflux a wide range of substrates and horizontal gene transfer of genetic material encoding multiple resistance genes between different species within the polymicrobial biofilm. Antimicrobial resistance is an increasing threat caused by multiple factors including cross-resistance, and it is a global health concern. This review focuses on current research on antimicrobial and antibiotic resistance and cross-resistance found between antimicrobials and antibiotics commonly used in woundcare to evaluate the significance of this acquired antibiotic resistance. Furthermore, the review discusses the significance of antimicrobial tolerance and the role biofilms play in enhancing antibiotic resistance.

Hypothermic, initially oxygen-free, controlled limb reperfusion for acute limb ischemia.

BACKGROUND: Controlled limb reperfusion has been shown to prevent the deleterious effects of ischemia-reperfusion (IR) syndrome following revascularization of acute limb ischemia (ALI). To reduce the production of cell-toxic oxygen-free radicals, we have established a new initially oxygen-free, hypothermic, heparin-coated perfusion and hemofiltration system and report on our first results. METHODS: In a retrospective single-center study, controlled limb reperfusion was applied in 36 patients (64.7 ± 15 years) with ALI of category IIA to III (33.7 ± 20.7 hr ischemic time). 52.8% had central (aortic and bifurcation) and 47.2% had peripheral (common iliac artery and distal) vascular occlusions. The common femoral artery and vein were cannulated, and a hypothermic (22°C), initially oxygen-free, potassium-free ringer's solution was perfused using a heparin-coated extracorporeal membrane oxygenation (ECMO) and hemofiltration system with low-dose heparinization. Thirty-day mortality, clinical recovery of neurological dysfunction, limb amputation, and fasciotomy rate were analyzed. Laboratory parameters associated with ischemia and IR injury were determined. RESULTS: Average perfusion time was 94 ± 35 min. Thirty-day mortality was 27.8%. 55.5% of patients showed complete recovery of motor and sensory dysfunction. A total of 27.8% of patients developed a compartment syndrome and required fasciotomy. Lower leg amputation was necessary in 11.1% of patients. Lactate levels were reduced in ischemic limbs by 25.3% within 60 min (P < 0.05). Preoperative negative base excess of -1.96 ± 0.96 mmol/L was equalized after 12 hr (P < 0.05), while pH stayed balanced at 7.4. Serum potassium stayed within normal limits throughout 24 hr, and therefore systemic hyperkalemia was prevented and imminent metabolic acidosis was corrected. CONCLUSIONS: An initially oxygen-free, hypothermic, heparin-coated ECMO counteracts local and systemic effects of IR injury. Reduced mortality and morbidity might result from this new treatment, although this could not be conclusively proven in our study. A prospective, randomized controlled trial is needed to prove superiority of this new concept.

Fundamentals of randomized clinical trials in wound care: reporting standards.

In wound care research, available high-level evidence according to the evidence pyramid is rare, and is threatened by a poor study design and reporting. Without comprehensive and transparent reporting, readers will not be able to assess the strengths and limitations of the research performed. Randomized clinical trials (RCTs) are universally acknowledged as the study design of choice for comparing treatment effects. To give high-level evidence the appreciation it deserves in wound care, we propose a step-by-step reporting standard for comprehensive and transparent reporting of RCTs in wound care. Critical reporting issues (e.g., wound care terminology, blinding, predefined outcome measures, and a priori sample size calculation) and wound-specific barriers (e.g., large diversity of etiologies and comorbidities of patients with wounds) that may prevent uniform implementation of reporting standards in wound care research are addressed in this article. The proposed reporting standards can be used as guidance for authors who write their RCT, as well as for peer reviewers of journals. Endorsement and application of these reporting standards may help achieve a higher standard of evidence and allow meta-analysis of reported wound care data. The ultimate goal is to help wound care professionals make better decisions for their patients in clinical practice.

Veno-venous perfusion to cool and rewarm in thoracic and thoracoabdominal aortic aneurysm repair.

BACKGROUND: Femoro-femoral veno-arterial perfusion is an established circulatory support and cooling method for thoracic- and/or thoracoabdominal aortic aneurysm repair. However, retrograde perfusion through femoral arteries can lead to retrograde cerebral embolization and neurologic dysfunction after surgery. To avoid these complications, we have established a femoro-femoral veno-venous perfusion technique and evaluated its safety and effectiveness in elective and nonelective patients. METHODS: Common femoral veins were cannulated bilaterally percutaneously following systemic low-dose heparinization (100 IU/kg body weight). Venous blood was drained from drainage of the inferior vena cava, and venous return followed through the superior vena cava. After proximal aortic cross-clamping, veno-venous perfusion was switched to veno-arterial antegrade perfusion through the distal descending thoracic aorta to achieve spinal and visceral perfusion or through iliac arteries for distal perfusion combined with selective renovisceral blood perfusion. After completion of aortic repair, the arterial cannula was removed and the patient rewarmed just by switching back to veno-venous perfusion. Gas and temperature exchange as well as relevant hemodynamic parameters were recorded prospectively and analyzed retrospectively in 25 consecutive patients including 15 nonelective cases. RESULTS: Percutaneous insertion of outflow (28F cannula) and inflow (18F cannula) venous cannulae was complication-free and allowed unrestricted perfusion in all 25 patients. Veno-venous perfusion allowed effective cooling (mean body temperature 36.6 ± 0.6°C to 31.6 ± 2.1°C, P = .001 compared with start of cooling) and re-warming (mean body temperature 30.5 ± 3°C to 36.3 ± 0.8°C, P = .03 compared with start of re-warming). Hemodynamic as well as pulmonary parameters remained remarkably stable during surgical dissection and single lung ventilation even in nonelective cases. There was no complication associated with the perfusion technique during surgery. CONCLUSIONS: Transfemoral veno-venous cooling and re-warming results in remarkable hemodynamic stability during open repair of thoracic- and/or thoracoabdominal aortic aneurysms and eliminates the need for retrograde arterial perfusion and its inherent risks.

EpiDex® Swiss field trial 2004-2008.

BACKGROUND: Approximately 20% of leg ulcers remain unresponsive to the best conservative standard of care. So far, these patients could either receive conventional skin grafts or had to accept their intractable wound. Skin substitutes from cell culture may represent a promising alternative to heal a major part of these patients on a non-surgical, potentially more cost-effective basis. OBJECTIVE: To systematically evaluate the first 68 patients treated in Switzerland (Swiss EpiDex® field trial 2004-2008). METHODS: Retrospective study on EpiDex treatment of a complete consecutive series of 68 patients with chronic wounds (66 chronic leg ulcers, 2 sores) unresponsive to best conservative standard of care. The primary end point was complete wound closure within 9 months after transplantation, the secondary end points change of wound surface area, pain reduction and overall judgement by the patient. Adverse effects were infection, dermatitis and others. Calculation of treatment costs was made. RESULTS: By the end of the study, 50/68 (74%) of patients had their wound completely healed [venous 29/37 (78%); mixed 7/9 (78%); others 14/22 (64%)]; 10/68 (15%) had the wound surface area reduced by >50%, and 8/68 (12%) did not respond to the EpiDex treatment. Wound pain disappeared completely in 78% and partially in 13%. Fifteen patients (22%) received antibiotics for wound infection, and 2 (3%) developed dermatitis (not related to the local therapy). Average treatment costs for venous ulcers amounted to EUR 5,357, compared to EUR 5,722-8,622 reimbursed according to the German DRG system (2010) for an in-patient skin graft. CONCLUSION: EpiDex may effectively heal up to three quarters of recalcitrant chronic leg ulcers. Thus, it represents an intermediate step to avoid costly in-patient split-skin mesh graft treatments. Patients remain mobilized, and a donor site is avoided. Large wound size or a necrotic wound bed limit the use of EpiDex. Otherwise, it offers the opportunity to avoid conventional skin grafts in a significant number of chronic leg ulcer patients.