Wound Bed Preparation 2024: Delphi Consensus on Foot Ulcer Management in Resource-Limited Settings.

GENERAL PURPOSE: To review a practical and scientifically sound application of the wound bed preparation model for communities without ideal resources. TARGET AUDIENCE: This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and registered nurses with an interest in skin and wound care. LEARNING OBJECTIVES/OUTCOMES: After participating in this educational activity, the participant will:1. Summarize issues related to wound assessment.2. Identify a class of drugs for the treatment of type II diabetes mellitus that has been shown to improve glycemia, nephroprotection, and cardiovascular outcomes.3. Synthesize strategies for wound management, including treatment in resource-limited settings.4. Specify the target time for edge advancement in chronic, healable wounds.

Chronic wound management in low-resource settings deserves special attention. Rural or underresourced settings (ie, those with limited basic needs/healthcare supplies and inconsistent availability of interprofessional team members) may not have the capacity to apply or duplicate best practices from urban or abundantly-resourced settings. The authors linked world expertise to develop a practical and scientifically sound application of the wound bed preparation model for communities without ideal resources. A group of 41 wound experts from 15 countries reached a consensus on wound bed preparation in resource-limited settings. Each statement of 10 key concepts (32 substatements) reached more than 88% consensus. The consensus statements and rationales can guide clinical practice and research for practitioners in low-resource settings. These concepts should prompt ongoing innovation to improve patient outcomes and healthcare system efficiency for all persons with foot ulcers, especially persons with diabetes.

Dehydrated human amnion/chorion membrane allograft with spongy layer to significantly improve the outcome of chronic non-healing wounds.

We investigated the healing effect of a new dehydrated amnion/chorion membrane with a spongy layer over a 30-month period in 32 patients with 53 chronic non-healing wounds of different aetiologies. Wounds with <40% surface reduction after 4 weeks of best wound treatment underwent weekly allograft application by a certified wound specialist based on national guidelines and a standardised protocol until complete healing or definite treatment interruption. The main outcome measure was the percentage of wound surface reduction from baseline calculated using digital planimetry follow-up photographs. Overall, 38 (71.7%) wounds presented a favourable outcome (70%-100% area reduction), with 35 (66%) completely healing over a median time of 77 days (range 29-350 days). Favourable outcomes were observed in 75% of traumatic wounds, surgical wounds, venous leg ulcers and pressure injuries, as well as in 50% of ischaemic wounds. Wounds being present <12 months were significantly more likely to have a favourable outcome than more long-standing wounds (χ2 = 7.799; p = 0.005; OR = 3.378; 95% CI, 1.410-8.092). Thus, treatment with dehydrated amnion/chorion membrane with a spongy layer improves the outcome of non-healing wounds of different aetiologies and, therefore, has to be considered early in the management of refractory wounds.

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.

Symptomatic internal carotid artery stenosis in the presence of a persistent primary hypoglossal artery.

OBJECTIVES: Anatomic variations of the extracranial carotid artery are rare. Persistent primitive hypoglossal artery appears with a reported incidence between 0.03% and 0.2%. We report a case of recurrent transient ischemic attacks originating from proximal internal carotid artery stenosis associated with ipsilateral persistent primitive hypoglossal artery and give a review of the existing literature. METHODS: A 78-year-old patient with a medical history of two previous transient ischemic attacks consulted our emergency department with an acute left hemispheric stroke. Intravenous thrombolysis permitted complete resolution of symptoms. Concurrent Computed Tomography (CT) and Magnetic Resonance (MR) angiography revealed an unstable plaque causing 50% stenosis of the left internal carotid artery with a persistent primitive hypoglossal artery dominantly perfusing the posterior circulation, and bilateral hypoplastic vertebral arteries. RESULTS: Uneventful carotid artery stenting using a proximal protection device was performed, and the patient was discharged after 12 days. Six months follow-up was uneventful with a patent stent in the internal carotid artery. CONCLUSIONS: Treatment of symptomatic carotid artery stenosis in the presence of persistent primitive hypoglossal artery is challenging. Management should be driven by patients' co-morbidities, the anatomical localization of the lesions and local expertise. In the case of a high origin of the persistent primary hypoglossal artery, carotid artery stenting with the use of a proximal cerebral protection device is probably the preferred and simplest approach.

Surfactants: Role in biofilm management and cellular behaviour.

Appropriate and effective wound cleaning represents an important process that is necessary for preparing the wound for improved wound healing and for helping to dislodge biofilms. Wound cleaning is of paramount importance to wound bed preparation for helping to enhance wound healing. Surfactant applications in wound care may represent an important area in the cleaning continuum. However, understanding of the role and significance of surfactants in wound cleansing, biofilm prevention and control, and enhancing cellular viability and proliferation is currently lacking. Despite this, some recent evidence on poloxamer-based surfactants where the surfactants are present in high concentration have been shown to have an important role to play in biofilm management; matrix metalloproteinase modulation; reducing inflammation; and enhancing cellular proliferation, behaviour, and viability. Consequently, this review aims to discuss the role, mode of action, and clinical significance of the use of medically accepted surfactants, with a focus on concentrated poloxamer-based surfactants, to wound healing but, more specifically, the role they may play in biofilm management and effects on cellular repair.

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.

Efficacy of Concentrated Surfactant-Based Wound Dressings in Wound Repair and Biofilm Reduction.

Objective: This study was set up to evaluate the efficacy of a concentrated surfactant-based wound dressing (with and without silver sulfadiazine [SSD]) on wound repair, by investigating their ability to enhance human dermal fibroblast proliferation and viability. In addition, the wound dressings were evaluated for their ability to suppress biofilms in a three-dimensional (3D) in vitro wound biofilm model and modulate the inflammatory cytokine interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNFα). Approach: Problematic biofilms are well known to affect fibroblast and keratinocyte viability. To assess wound repair and inflammatory cytokine modulation, a direct cytotoxicity assay and a 3D keratinocyte-fibroblast model were employed. Results: At 1 and 7 days posttreatment, the non-antimicrobial dressing was noncytotoxic and the antimicrobial dressing was moderately cytotoxic to adult human dermal fibroblasts cells. Within the 3D wound model, the biofilm demonstrated a decelerating effect on wound closure and a decrease in viable cells. When the non-antimicrobial- and antimicrobial-based concentrated surfactant-based wound dressing was applied to the wound model, reduced biofilm was observed. The application of wound dressings to the biofilm-infected wound also resulted in a reduction of IL-6 and TNFα. The concentrated surfactant-based wound dressing without an antimicrobial was shown to enhance cellular viability and migration. Innovation and Conclusion: We have demonstrated the ability of a surfactant-based wound dressing to minimize the deleterious effects of a wound biofilm, modulate the secretion of inflammatory cytokines, and enhance cellular proliferation in a biofilm-infected wound model. Furthermore, the non-antimicrobial-based concentrated surfactant dressings did not affect cellular viability and therefore represents a multifaceted approach to the treatment of wounds infected with biofilms.

Cell salvage in acute and chronic wounds: a potential treatment strategy. Experimental data and early clinical results.

On 9 May 2018, the authors took part in a closed panel discussion on the impact of cell salvage in acute and chronic wounds. The goal was to deliberate the possible use of plurogel micelle matrix (PMM) as a new treatment strategy for wound healing and the authors openly shared their experiences, thoughts, experimental data and early clinical results. The outcome of the panel discussion has been abridged in this paper. The cell membrane consists of a lipid bilayer, which provides a diffusion barrier separating the inside of a cell from its environment. Cell membrane injury can result in acute cellular necrosis when defects are too large and cannot be resealed. There is a potential hazard to the body when these dying cells release endogenous alarm signals referred to as 'damage (or danger) associated molecular patterns' (DAMPs), which trigger the innate immune system and modulate inflammation. Cell salvage by membrane resealing is a promising target to ensure the survival of the individual cell and prevention of further tissue degeneration by inflammatory processes. Non-ionic surfactants such as poloxamers, poloxamines and PMM have the potential to resuscitate cells by inserting themselves into damaged membranes and stabilising the unstable portions of the lipid bilayers. The amphiphilic properties of these molecules are amenable to insertion into cell wall defects and so can play a crucial, reparative role. This new approach to cell rescue or salvage has gained increasing interest as several clinical conditions have been linked to cell membrane injury via oxidative stress-mediated lipid peroxidation or thermal disruption. The repair of the cell membrane is an important step in salvaging cells from necrosis to prevent further tissue degeneration by inflammatory processes. This is applicable to acute burns and chronic wounds such as diabetic foot ulcers (DFUs), chronic venous leg ulcers (VLUs), and pressure ulcers (PUs). Experimental data shows that PMM is biocompatible and able to insert itself into damaged membranes, salvaging their barrier function and aiding cell survival. Moreover, the six case studies presented in this paper reveal the potential of this treatment strategy.

The role of FDG PET/CT in therapy control of aortic graft infection.

PURPOSE: 18F-FDG PET/CT (PET/CT) is a useful tool for the diagnosis of aortic graft infection (AGI), but has rarely been used to influence therapeutic decisions during follow-up. We aimed to study the role of PET/CT in the long-term monitoring of patients. METHODS: Participants of the prospective Vascular Graft Infection Cohort Study (VASGRA) were included if they had microbiologically proven AGI. We quantified the metabolic activity in PET/CT by using maximum standardized uptake value (SUVmax) and further classified it as being focal or diffuse. Multivariable linear regression models were fit using generalized estimating equations to investigate factors associated with SUVmax over time. RESULTS: Sixty-eight participants with AGI contributed to 266 PET/CTs including 36 examinations performed after stop of antimicrobial therapy. Higher C-reactive protein (CRP) (adjusted coefficient per log10 mg/L 0.05 [95% C.I. 0.02-0.08]) was associated with higher SUVmax. CRP, metabolic and clinical findings informed the decision to either start (medians of SUVmax 7.1 and CRP 31.5 mg/L; 100% focal uptake), escalate (SUVmax 9.5; CRP 31.5; 100% focal uptake), continue (SUVmax 6.0; CRP 9.95 mg/L; 90% focal uptake), or stop (SUVmax 4.3; CRP 3.5 mg/L; 61% focal uptake) antibiotic treatment. Of note, decisions to escalate or continue antibiotic treatment were taken despite normal CRP values in 12.5 and 35.7% of PET/CTs, respectively. CONCLUSIONS: Consecutive PET/CTs could influence the clinical decision-making in patients with AGI in the near future. More studies on the use of PET/CT in case of aortic graft infection may offer the potential for individualized treatment approaches. CLINICALTRIALS. GOV IDENTIFIER: NCT01821664.

Role of anaerobes in polymicrobial communities and biofilms complicating diabetic foot ulcers.

Infected tissues in the feet of people with diabetes in the form of a diabetic foot ulcer (DFU) present a complex pathology for clinicians to manage. This is partly attributed to the multi-factorial nature of the disease, which may include; altered foot architecture leading to excessive plantar pressures and frictional forces peripheral arterial disease and loss of protective sensation. In addition, to the above co-morbid variables, it is understood that a delayed wound healing state may be perpetuated by the presence of microorganisms residing in the wound tissue. The microbiology of chronic DFUs has often been reported as being polymicrobial. Of growing interest is the presence and potential role of anaerobic microorganisms in the pathology of DFUs and how they may contribute to the infective process or delayed healing. The presence of anaerobes in DFUs has been greatly underestimated, largely due to the limitations of conventional culture methods in identifying them from samples. Advancements in molecular and microscopy techniques have extended our view of the wound microbiome in addition to observing the growth and behaviour (planktonic or biofilm) of microorganisms in situ. This review paper will reflect on the evidence for the role and significance of anaerobes in DFUs and infection. A focus of this review will be to explore recent advancements in molecular genomics and microscopy techniques in order to better assess the roles of anaerobic bacteria in chronic DFUs and in biofilm-based wound care.

Mode of action of poloxamer-based surfactants in wound care and efficacy on biofilms.

Surfactants are widely used as detergents, emulsifiers, wetting agents, foaming agents, and dispersants in both the food and oil industry. Their use in a clinical setting is also common, particularly in wound care. Complicated or chronic wounds show clinical signs of delayed healing, persistent inflammation, and the production of non-viable tissue. These types of wounds also present challenges such as infection and potentially house antimicrobial-tolerant biofilms. The use of wound cleansers to aid cleaning and debridement of the wound is essential. A large proportion of skin and wound cleansers contain surfactants but there is only a small amount of data that shows the effectiveness of them in the enhancement of wound closure. This review paper aims to explore the available literature surrounding the use and mode of action of surfactants in wound healing, in particular Poloxamer 188 (Pluronic F-68) and Poloxamer 407 (Pluronic F-127), and also uncover the potential mechanisms behind the enhancement of wound healing and comparison to other surfactants used in wound care. Furthermore, the presence of a microbial biofilm in the wound is a significant factor in delayed wound healing. Therefore, the effect of clinically used surfactants on biofilms will be discussed, with emphasis on poloxamer-based surfactants.

[Leg ulcers (ulcus cruris): The frequent macrovascular causes]. / Ulcus cruris: Die häufigen, makrovaskulären Ursachen.

Leg ulcers (ulcus cruris): The frequent macrovascular causes Abstract. Four pathologies make up the macrovascular etiologies of leg uclers: Venous leg ulcers (50 %), mixed venous-arterial leg ulcers (20 %), arterial leg ulcers (5 %), and Martorell hypertensive ischemic leg ulcer (5 %). The remaining 20 % concern a large array of other etiologies. Every leg ulcer requires vascular (arterial and venous) work-up, that can be completed with microbiology, biopsy, and more in-depth internal diagnostics, as indicated. Venous leg ulcers are treated with compression therapy. Incompetent saphenous veins and tributaries are abolished if the deep venous system is patent. Occluded iliac veins are recanalised and stented, as possible. Refractory venous leg ulcers are grafted with split skin or punch grafts, depending on their surface. Extensive dermatolipofasciosclerosis may be tangentially removed by shave therapy or fasciectomy, that can be combined with negative pressure wound treatment (NPWT). Skin equivalents are an alternative to treat superficial venous leg ulcers that fail to epithelialise. Their indication in the treatment of more complex leg ulcers still needs to be better investigated and understood. The use of dermal matrices leads to more stable scars. Mixed venous-arterial leg ulcers heal slower and recur more frequently. Compression needs to be reduced. Refractory cases require arterial revascularisation, to transform the mixed venous-arterial into a venous leg ulcer. Arterial leg ulcers require arterial revascularization and split skin graft. Martorell hypertensive ischemic leg ulcer is still underrecognised and often confounded with with pyoderma gangrenosum, which leads therapy into a wrong direction. Necrosectomy, antibiotic treatment in the presence of relevant bacterial superinfection, and repeated split skin grafts eventually heal the vast majority of these extremely painful and potentially mortal wounds.

Consensus on Wound Antisepsis: Update 2018.

Wound antisepsis has undergone a renaissance due to the introduction of highly effective wound-compatible antimicrobial agents and the spread of multidrug-resistant organisms (MDROs). However, a strict indication must be set for the application of these agents. An infected or critically colonized wound must be treated antiseptically. In addition, systemic antibiotic therapy is required in case the infection spreads. If applied preventively, the Wounds-at-Risk Score allows an assessment of the risk for infection and thus appropriateness of the indication. The content of this updated consensus recommendation still largely consists of discussing properties of octenidine dihydrochloride (OCT), polihexanide, and iodophores. The evaluations of hypochlorite, taurolidine, and silver ions have been updated. For critically colonized and infected chronic wounds as well as for burns, polihexanide is classified as the active agent of choice. The combination 0.1% OCT/phenoxyethanol (PE) solution is suitable for acute, contaminated, and traumatic wounds, including MRSA-colonized wounds due to its deep action. For chronic wounds, preparations with 0.05% OCT are preferable. For bite, stab/puncture, and gunshot wounds, polyvinylpyrrolidone (PVP)-iodine is the first choice, while polihexanide and hypochlorite are superior to PVP-iodine for the treatment of contaminated acute and chronic wounds. For the decolonization of wounds colonized or infected with MDROs, the combination of OCT/PE is preferred. For peritoneal rinsing or rinsing of other cavities with a lack of drainage potential as well as the risk of central nervous system exposure, hypochlorite is the superior active agent. Silver-sulfadiazine is classified as dispensable, while dyes, organic mercury compounds, and hydrogen peroxide alone are classified as obsolete. As promising prospects, acetic acid, the combination of negative pressure wound therapy with the instillation of antiseptics (NPWTi), and cold atmospheric plasma are also subjects of this assessment.

Efficacy of a surfactant-based wound dressing on biofilm control.

The aim of this study was to evaluate the efficacy of both a nonantimicrobial and antimicrobial (1% silver sulfadiazine-SSD) surfactant-based wound dressing in the control of Pseudomonas aeruginosa, Enterococcus sp, Staphylococcus epidermidis, Staphylococcus aureus, and methicillin-resistant S. aureus (MRSA) biofilms. Anti-biofilm efficacy was evaluated in numerous adapted American Standards for Testing and Materials (ASTM) standard biofilm models and other bespoke biofilm models. The ASTM standard models employed included the Minimum biofilm eradication concentration (MBEC) biofilm model (ASTM E2799) and the Centers for Disease Control (CDC) biofilm reactor model (ASTM 2871). Such bespoke biofilm models included the filter biofilm model and the chamberslide biofilm model. Results showed complete kill of microorganisms within a biofilm using the antimicrobial surfactant-based wound dressing. Interestingly, the nonantimicrobial surfactant-based dressing could disrupt existing biofilms by causing biofilm detachment. Prior to biofilm detachment, we demonstrated, using confocal laser scanning microscopy (CLSM), the dispersive effect of the nonantimicrobial surfactant-based wound dressing on the biofilm within 10 minutes of treatment. Furthermore, the non-antimicrobial surfactant-based wound dressing caused an increase in microbial flocculation/aggregation, important for microbial concentration. In conclusion, this nonantimicrobial surfactant-based wound dressing leads to the effective detachment and dispersion of in vitro biofilms. The use of surfactant-based wound dressings in a clinical setting may help to disrupt existing biofilm from wound tissue and may increase the action of antimicrobial treatment.

New Surfactant-based Dressing Product to Improve Wound Closure Rates of Nonhealing Wounds: A European Multicenter Study Including 1036 Patients.

OBJECTIVE: A new surfactant-based biomaterial containing the antimicrobial 1% silver sulfadiazine (SSD) was developed at the University of Virginia (Charlottesville, VA) to improve outcomes for nonhealing wounds. This study's objective was to clinically test the wound care outcomes of the new surfactant-based antimicrobial wound dressing (SAWD) in a multicenter trial. METHODS AND MATERIALS: This cohort study enrolled 1036 patients with any nonhealing wound of > 3 months duration not responding to standard-of-care treatments from 10 wound care centers in 7 European countries. The SAWD was used for all wound types at all stages of complexity, healing, and severity. Data collection ranged from 6 months to 2 years and measured the percentage of patients achieving wound closure and time to complete closure. RESULTS: Of the 1036 patients, 70% achieved wound closure, 24.6% were still in treatment at data collection, and 5.4% had a therapy change. The majority (56%) of these non-healing wounds achieved wound closure within 11 weeks. Patients were treated with the SAWD for 3 weeks to more than 1 year with no complications or adverse effects from long-term SSD antimicrobial use. CONCLUSION: Ten centers concluded that the new SAWD provided positive results (improved wound closure rates, reduction of inflammation, pain, and odor), improvements in clinical application (faster and easier dressing change), and improved patient compliance.

Prosthetic Vascular Graft Infections: Bacterial Cultures from Negative-Pressure-Wound-Therapy Foams Do Not Improve Diagnostics.

We analyzed the diagnostic value of microorganisms cultured from negative-pressure-wound-therapy (NPWT) foam samples compared to that of microorganisms cultured from deep tissue samples from patients with vascular graft infections. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were 58%, 86%, 81%, and 66%, respectively. The diagnostic value of microbiological cultures from NPWT foams was poor.