Local environment of chronic wounds under synthetic dressings

Local wound environment under oxygen-permeable and oxygen-nonpermeable dressings in patients with chronic ulcers was investigated. The oxygen tensions under both these dressings were very low or zero. Wound fluid was more acidic under the nonpermeable hydrocolloid dressing than under the oxygen-permeable polyurethane dressing. Bacterial growth studied in vitro was retarded at the more acidic pH similar to that found under the hydrocolloid dressing. Viable and functioning neutrophils were found under both the polyurethane and hydrocolloid dressings, with a greater percentage of viable cells under the polyurethane film. Our data suggest that these synthetic dressings create hypoxic conditions in which wound healing occurs whether or not the dressing is permeable to oxygen. Furthermore the local wound environment can be modified by use of synthetic dressings.     

Tolerability and efficacy of hydrocolloid dressings in the treatment of venous leg ulcers under tropical conditions: an open prospective study.

In the Western world, hydrocolloid dressings are widely used in wound treatment. However, little is known about their tolerability and efficacy under tropical conditions. The purpose of this study was to assess the tolerability and efficacy of a hydrocolloid dressing in combination with short stretch compressive bandages under tropical conditions. Seventeen patients with venous leg ulcers attending an outpatient clinic in Surinam were enrolled in the study for a period of 6 weeks. Swabs for bacterial cultures were taken at the beginning and end of the study. All ulcers showed a good healing tendency. Percentage of granulation tissue in the ulcers improved from mean 27% at start to 92% at the end. Mean circumference at start was 9.9 cm, at the end 4.9 cm. Exudation diminished from moderate in six and severe in eight ulcers, to moderate in 10 and almost none in two ulcers. In general, the dressing was very well accepted, pain was never reported. Leakage was noticed 39 times in the 164 dressing changes. This study revealed no differences in the rate of bacterial infections or colonization of wounds compared with studies performed in temperate regions. Our data indicate that hydrocolloid dressings can be used under tropical conditions.     

Management of leg ulcers with hydrocolloid occlusive dressing

Twenty-two patients with 31 leg ulcers of various causes received local wound management consisting of the application of an adhesive hydrocolloid (HC) occlusive dressing (DuoDerm). Group 1 comprised 15 patients (11 outpatients) with 19 ulcers. Approximately two thirds (12/19) of the ulcers healed when treated solely with the HC dressing; mean treatment time was 57 days. Group 2 comprised seven hospitalized patients with at least two leg ulcers of similar size and distribution. The 20 ulcers in the seven patients were treated with either mild topical antimicrobial wet dressings (Sweitzer's 1:32 solution) or HC dressings, with each patient serving as his own "control." All 20 ulcers healed; the average time to healing was 44 days with HC dressing and 42 days with wet dressing management. Most of the patients reported convenience in management and substantial relief of pain with the use of HC dressings.     

Comparison of a hydrocolloid dressing and paraffin gauze in the treatment of venous ulcers

In-patients with venous leg ulcers showed increased healing rates with a hydrocolloid dressing (Granuflex), as compared with a traditional paraffin gauze dressing (Jelonet), in a randomized sequential crossover trial, although the difference was not statistically significant. Bacteriological studies showed that the hydrocolloid dressing favoured growth of both aerobes and anaerobes in significantly greater numbers compared with paraffin gauze. Heavy bacterial colonization had no effect on the healing rates of the ulcers. Granuflex is said to produce an anaerobic environment--survival of Pseudomonas aeruginosa, a strict aerobe, under Granuflex dressings, makes this seem unlikely.     

Investigation of adhesion of modern wound dressings: a comparative analysis of 56 different wound dressings

Introduction In the process of chronic wound care, adhesive wound dressings may cause pain and injury in the wound environment during dressing changes. At present, no standardized test procedures are available for the investigation of adhesion of wound dressings. Therefore, our study aimed to test the adhesion of different wound dressings on steel as well as on healthy skin. Methods Within an open, comparative study, the adhesive areas of 56 wound dressings were investigated. The adhesives were categorized into acrylate (n = 23), silicone (n = 9), hydrocolloid (n = 17) and polyurethane groups (n = 7). Using an especially modified testing machine, the adhesion of the wound dressings was measured on steel as well as on the skin of healthy study participants, in compliance with the European EN 1939:2003 standard. Results The energy required to remove the wound dressings from human skin, was measured in Newton (N) and the following median values were obtained: hydrocolloid (2.25 N) > acrylate (1.14 N) > polyurethane (0.9 N) > silicone (0.7 N). The subjective pain intensity during the removal of the wound dressings was recorded using the visual analogue scale (VAS) with values ranging from 0 to 10. For hydrocolloid, it was 6.8, for acrylate 4.9, for polyurethane 3.1 and for silicone 2.5 points VAS. In comparison with human skin, the adhesion of wound dressings was significantly higher on steel (P < 0.0001), but was different for the different groups of wound dressings. Moreover, there was a statistically significant correlation between the adhesion and pain intensity (correlation coefficient 0.806; P = 0.01). Conclusion The knowledge about the widely differing adhesion properties of different wound dressings on the skin of patients should nowadays be considered during the individual selection of the applied products. Based on these data, different types of wound dressings could be developed, guaranteeing a good adhesion and a low traumatic risk when removed.     

Wound Dressings: Selecting the Most Appropriate Type

Appropriate wound dressing selection is guided by an understanding of wound dressing properties and an ability to match the level of drainage and depth of a wound. Wounds should be assessed for necrosis and infection, which need to be addressed prior to selecting an ideal dressing. Moisture-retentive dressings include films, hydrogels, hydrocolloids, foams, alginates, and hydrofibers and are useful in a variety of clinical settings. Antimicrobial-impregnated dressings can be useful in wounds that are superficially infected or are at higher risk for infection. For refractory wounds that need more growth stimulation, tissue-engineered dressings have become a viable option in the past few decades, especially those that have been approved for burns, venous ulcers, and diabetic ulcers. As wounds heal, the ideal dressing type may change, depending on the amount of exudate and depth of the wound; thus success in wound dressing selection hinges on recognition of the changing healing environment.     

Comparison of the open technique with a new wound dressing,H2460, in the healing of an acute wound after laser skin resurfacing

Background: Applying various dressings or leaving the treated area open are two techniques in use after laser skin resurfacing (LSR). Objective: This study was conducted to compare healing of an acute wound using a new hydrocolloid dressing, H2460, with the open technique. Methods: Immediately after LSR, one side was covered with the new hydrocolloid dressing H2460 and the other side was left open. Participants were instructed to clean the open side four times a day and replace the H2460 dressing if it was dislodged. Results: In the volunteers' and investigator's evaluations, the new dressing H2460 generally outperformed the ‘open’ technique. At the 1‐month follow‐up, eight of 10 volunteers reported that the H2460 side resulted in better healing; two of 10 volunteers felt there was no difference between the two sides for final outcome and none believed that the open side had better healing. Overall, the H2460 side healed better in the majority of participants as graded by the blinded observer (60%) and participant themselves (80%). Conclusion: The new hydrocolloid dressing H2460 is a better and suitable alternative to the open technique to manage an acute wound after LSR.     

Bacteriology, inflammation, and healing: a study of nanocrystalline silver dressings in chronic venous leg ulcers

BACKGROUND: Healing of venous leg ulcers (VLUs) is often stalled despite compression therapy. Increased bacterial burden and chronic inflammation are 2 factors that may prevent these chronic VLUs (CVLUs) from healing. There is evidence that nanocrystalline silver dressings may reduce bacterial levels, decrease the chronic inflammatory response, and thus promote wound healing. OBJECTIVE: To determine the effects of a nanocrystalline silver barrier dressing on wound microflora, wound inflammation, and healing in CVLUs. METHOD: Stalled VLUs in 15 patients were managed using nanocrystalline silver dressings under 4-layer compression bandages. Paired skin biopsies at baseline and at an average of study week 6.5 were analyzed for bacteria and inflammatory infiltrates. Serum silver levels were monitored, and wound healing was assessed using planimetry. RESULTS: VLUs in 4 patients healed, and 8 other patients completed the 12-week study. There was a significant reduction in the log10 total bacterial count between baseline and final biopsies (P = .011). Greater numbers of lymphocytes were associated with an increased reduction of ulcer size at week 6.5 and final assessment at week 12 (P < .05). Heavy neutrophilic infiltration in skin biopsies at week 6.5 was associated with high bacterial counts and delayed healing (P = .037). The median reduction in ulcer surface area for all patients was 83.5%. Serum silver levels increased slightly, but values were within the normal range. CONCLUSION: A nanocrystalline silver dressing combined with 4-layer bandaging was safe and successful in promoting healing in stalled CVLUs. Healing was associated with a reduction in wound bacteria and neutrophilic inflammation with an associated persistent or high lymphocyte count, as determined by wound biopsy.     

Comparison of SureSkin®, DuoDerm E® and Jelonet® Gauze in split skin donor sites – a clinical and histologial evaluation

Background : The hydrocolloid dressings DuoDerm E®, and SureSkin® were compared to each other and Jelonet®/Gauze dressing served as the control.
Methods : In 10 split skin donor sites the 3 dressings were tested.
Results : DuoDerm E® and SureSkin® healed the donor sites in 8.5 ± 0.8 days compared to the control with a heating time of 12 ± 1.6 days. Histological biopsies confirmed the clinical results.
Conclusions : It was concluded that SureSkin® is equal to DuoDerm E®in healing split donor sites, and that hydrocolloid dressings produce 33% faster healing limes.     

Photorejuvenation using intense pulsed light: my technique

Background. It has been reported that the final outcome of laser resurfacing still depends to a large degree on the efficiency of the post laser resurfacing wound care in promoting wound healing and preventing early and late complications.

Objective. The objective of this study was to evaluate and compare a new hydrocolloid dressing, H2460, with Flexzan^TM for healing of an acute wound after laser skin resurfacing (LSR).

Methods. Ten volunteers received LSR of the peri‐orbital area with an erbium:YAG laser. Identical parameters were used on both sides: 2 J, 5 mm spot, 8 Hz, 300 µs pulse, two passes on the upper eyelids, four passes on the lower eyelids and six passes on the crow's feet area. Soon after the LSR, one side was covered with Flexzan dressing and the other side was covered with a new hydrocolloid dressing – H2460. The side of the dressing was randomized by alternating both dressings. All volunteers were evaluated and digitally photographed every day for a week and at 1 month after LSR. The degree of erythema, swelling, bleeding, oozing, crusting, pigmentary changes, scarring, discomfort, itching, burning, ease of application of dressings, initial adhesion, overall adhesion, leakage of fluid, maceration of surrounding skin, ease of removal and adhesive residue upon removal were documented.

Results. In all volunteer and investigator's evaluations, the new dressing, H2460, achieved far better results than Flexzan in each category. After a 1‐week follow‐up all volunteers and the investigator evaluated the H2460 side as: healed better, simple to use, and caused less discomfort in 10 out of 10 volunteers. The blinded observer's assessment showed that the Flexzan side healed better in one volunteer.

Conclusion. The new dressing, H2460, is a better and suitable alternative to Flexzan as a post LSR dressing.     

Extravasation of macromolecules and possible trapping of transforming growth factor-β in venous ulceration

The pathogenesis of venous ulceration is thought to involve formation of pericapillary fibrin cuffs as a result of venous hypertension, and a recent hypothesis suggests that extravasated plasma proteins may bind or trap growth factors. We have compared the tissue distribution of fibrin cuffs, plasma proteins, procollagen, and transforming growth factors (TGF-β1 and TGF-β2) within venous ulcers and normally healing graft donor sites. In venous ulcers, the papillary dermis and the ulcer bed contained convoluted capillaries with phosphotungstic acid haematoxylin-positive pericapillary fibrin cuffs. By immunohistochemical staining, the cuffs were positive for actin, and contained massively redundant lamellae of basement membrane material which stained positive for type IV collagen. Extravasated factor XHIa and α₂-macroglobulin were present within the fibrin cuffs. increased numbers of type I procollagen positive fibroblasts, and increased TGF-β1 immunoreactiv-ity were present within the fibrin cuffs, but not in the provisional matrix in the ulcer bed around the cuffs. In contrast, in normally healing graft donor sites, tortuous capillaries and fibrin cuffs were absent, factor XHIa and α₁-macroglobulin were restricted to the lumina of vessels, and procollagen and TGF-/V immunoreactivity were present within the granulation tissue and adjacent dermal matrix at the wound margin. These observations suggest that growth factors critical in wound healing, such as TGF-β, are present within venous ulcers, but are abnormally distributed. Their distribution within fibrin cuffs and co-localization with extravasated plasma proteins, particularly α₂-macro-globulin, which is a recognized scavenger molecule for TGF-β and other growth factors, provides evidence for a possible ‘trapping’ of growth factors in venous ulcers.     

Studies on cytokines related to wound healing in donor site wound fluid

This study was performed to evaluate cytokines in donor-site wound fluids and to determine their effect on wound healing. A film dressing was applied to the donor-site wound of 24 patients immediately after a split-thickness skin graft was taken. On the 5th day after treatment, 2–3 ml of the fluid retained under the film dressing was collected by means of puncture with a syringe. Growth factors and cytokines considered to accelerate wound healing were present in relatively large amounts in the exudate. Very low concentrations of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) were detected by a commercially-available enzyme-linked immunosorbant assay (ELISA) kit. However, the presence of both growth factors in wound fluid could not be confirmed because of the possible cross-reactivity of the antibodies to other EGF and FGF family growth factors. In contrast, platelet derived growth factor (PDGF), interleukin-6 (IL-6), transforming growth factor- (TGF-) and TGF-β were present in relatively large amounts. The finding that certain cytokines coexist in a balanced state under the film dressing suggests that epithelization can proceed, since an adequate balance would insure proper regulation by the cytokine network. Our present study increases the likelihood that film or hydrocolloid dressings will be used more frequently in the future for treatment of burn wounds, ulcers or donor-site wounds since these dressings were shown to be more capable than ointments of retaining cytokines, particularly intrinsic growth factors secreted at the wound site.     

Pericapillary fibrin cuff: a histological sign of venous leg ulceration

The incidence of pericapillary fibrin cuffs was investigated in 49 biopsies of venous leg ulcers and 67 biopsies of leg ulcers of non-venous etiology. Pericapillary fibrin cuffs were seen in 28 biopsies (57.1%) of venous leg ulcers, but only in 11 biopsies (16.4%) of non-venous leg ulcers. In the venous leg ulcers pericapillary fibrin cuffs occurred predominantly near the ulcer surface and around dilated capillaries. Dilation of the capillaries and inflammation probably contribute more to the pathogenesis of pericapillary fibrin cuffs than venous hypertension.     

Superabsorbent wound dressings versus foams dressings for the management of moderate-to-highly exuding venous leg ulcers in French settings: An early stage model-based economic evaluation

Venous leg ulcers (VLUs) are the most common hard-to-heal ulcers associated with the high humanistic and economic burden. Especially clinically challenging are moderate-to-highly exuding venous leg ulcers, and current management guidelines recommend several different wound dressings for this indication.The study aimed to determine the cost-effectiveness of managing moderate-to-highly exuding venous leg ulcers with superabsorbent wound dressings versus foams dressings in French settings from Haute Autorité de Santé perspective.For evidence synthesis decision-analytic model was developed in line with international and French good modelling practices recommendations. All model inputs were informed by data identified through systematic literature reviews that, in our best knowledge, represent the best available evidence at this moment.According to the prediction from this early stage health economic evaluation, using superabsorbent wound dressings versus foam dressings mix in patients with moderate-to-highly exuding leg ulcers in French settings will result in an improved healing rate of 2.58%, incremental HRQoL of 0.143 QALWs and total direct cost savings of € 435 (USD 473) per patient over six months period.The clinical outcomes results from this evaluation are in line with management guidelines that have recommended superabsorbent wound dressings as a first-line choice in the therapy of moderate-to-highly exuding venous leg ulcers. In addition, this evaluation demonstrates that using superabsorbent wound dressings will also lead to economic savings from the Haute Autorité de Santé perspective.     

Expression of tight‐junction proteins in the inflamed and clinically uninvolved skin in patients with venous leg ulcers

Skin around venous leg ulcers (VLUs) is often inflamed and prone to contact sensitization. Expression of tight‐junction components (ZO‐1, occludin, and claudins 1 and 4) was studied by immunofluorescence in inflamed and noninflamed lower leg skin (both uncovered skin and skin occluded under hydrocolloid dressings) in patients with VLUs. No major differences were found in the expression of occludin and claudin‐4. ZO‐1 protein had stronger and more wide‐ranging expression in the inflamed epidermis. Expression of claudin‐1 was lost from the basal layer of the inflamed skin and skin under the hydrocolloid dressing. The skin on the lower legs affected by VLU may have altered expression of ZO‐1 and claudin‐1, similar to that seen in psoriatic plaques.     

Occlusive dressings and wound healing

Over the last 15 years, there has been explosive growth in the use of occlusive dressings as an aid to wound healing. In 1980 synthetic wound dressings were rarely sold, whereas in 1987 it was estimated that $350 million was spent on these dressings.¹ The number and variety of dressings on the market have also increased dramatically over the past decade to the point where more than 70 different brands exist today (Table 1). A dressing is said to be “occlusive” if a moist wound surface is maintained when the dressing is in place. Occlusive dressings prevent wound desiccation by inhibiting the transmission of water vapor from the wound surface to the atmosphere. A dressing that transmits moisture vapor at a rate lower than the rate of production of moisture by the underlying tissue creates a moist wound environment.Besides increasing the rate of epithelialization of wounds, other benefits of occlusive dressings are improving the granulation tissue in chronic wounds, providing a means of painless, autolytic debridement of necrotic ulcers,² and protecting the wound bed from environmental toxins and microorganisms. These dressings reduce wound pain and help produce a better cosmetic appearance, that is, a less noticeable scar. Finally, occlusive dressings may be cost effective in the treatment of certain wounds by decreasing the nursing time required for wound care. In this review, we discuss the numerous types and uses of occlusive dressings. The proposed mechanisms responsible for the beneficial effects of wound occlusion and the microbiology of occluded wounds are also explored.     

Water-filtered infrared A for the treatment of chronic venous stasis ulcers of the lower legs at home: a randomized controlled blinded study

Background Water‐filtered infrared A (wIRA) radiation can improve the healing of acute and chronic wounds both by thermal and thermic as well as by nonthermal and nonthermic effects. wIRA increases tissue temperature, oxygen partial pressure and perfusion. Objectives Investigation of the influence of wIRA on chronic venous stasis ulcers in an investigator‐initiated, randomized, controlled, blinded study. Methods Fifty‐one patients with nonhealing chronic venous stasis ulcers of the lower legs were treated with compression therapy, wound cleansing, nonadhesive wound dressings and 30 min irradiation [wIRA + visible light (VIS) or VIS alone], predominantly at home, five times per week over 9 weeks and an additional 4 weeks without irradiation. Results Compared with the control group with VIS alone, the group with wIRA + VIS showed better wound healing [after 9 weeks 85 vs. 67·5 on a 0–100 visual analogue scale (VAS), median difference 15, 95% confidence interval (CI) 3–30, P = 0·012], a higher percentage of patients with a healing trend [after 9 weeks 21 of 25 (84%) vs. 13 of 26 (50%), P = 0·023], better granulation (after 9 weeks 90 vs. 80 on a 0–100 VAS, median difference 10, 95% CI 0–30, P = 0·036), a trend to less exudation (after 5 weeks 30 vs. 55 on a 0–100 VAS, P = 0·075) and to faster reduction of the wound area (after 7 weeks 39% vs. 19·5% reduction of wound area, median difference 20·5%, 95% CI ?4–49%, P = 0·10; for wounds with an initial area < 10 cm²: after 13 weeks 92% vs. 47% reduction of wound area, median difference 30%, 95% CI 0–68%, P = 0·11). The main variable ‘Integral of relative ulcer area for each individual patient over time, standardized to an initial size of 1′ did not reach significance. The application of wIRA at home was easily manageable. Conclusions For the treatment of chronic venous stasis ulcers, the application of wIRA combined with phlebological therapy, compression therapy and wound dressing can be useful and can be recommended.     

Comparison of the open technique with a new wound dressing, H2460, in the healing of an acute wound after laser skin resurfacing.

BACKGROUND: Applying various dressings or leaving the treated area open are two techniques in use after laser skin resurfacing (LSR). OBJECTIVE: This study was conducted to compare healing of an acute wound using a new hydrocolloid dressing, H2460, with the open technique. METHODS: Immediately after LSR, one side was covered with the new hydrocolloid dressing H2460 and the other side was left open. Participants were instructed to clean the open side four times a day and replace the H2460 dressing if it was dislodged. RESULTS: In the volunteers' and investigator's evaluations, the new dressing H2460 generally outperformed the 'open' technique. At the 1-month follow-up, eight of 10 volunteers reported that the H2460 side resulted in better healing; two of 10 volunteers felt there was no difference between the two sides for final outcome and none believed that the open side had better healing. Overall, the H2460 side healed better in the majority of participants as graded by the blinded observer (60%) and participant themselves (80%). CONCLUSION: The new hydrocolloid dressing H2460 is a better and suitable alternative to the open technique to manage an acute wound after LSR.     

Treatment of venous ulcera cruris with dry wound dressings. Phase overlapping use of silver impregnated activated charcoal xerodressing

In a controlled randomized study on 40 patients with venous leg ulcers, monotherapy with a dry wound dressing (silver-impregnated--activated charcoal xerodressing; SIAX) was tested. The xerodressing was applied throughout the entire study and was compared with the conventional phase-adapted therapy using diverse topical modalities, e.g. as granulating ointments, zinc paste. etc. The parameters of wound healing were documented in the two randomized groups over 6 weeks and were statistically evaluated. In the statistical comparison of SIAX therapy (n = 19) and conventional therapy (n = 19) significant differences were found in favour of the SIAX group (increase of epithelialization, reduction of ulcer size; P less than 0.05). In addition, the ulcers of 6/19 patients (= 31.6%) treated with SIAX healed completely within the study period, in contrast to only 2/19 patients (= 10.5%) receiving conventional therapy. Exudate, granulation and colonization of the ulcers as well as odour, necroses, erythema and oedema of the surrounding areas were not significantly different. The study shows that a consistent therapy performed with dry wound dressings such as SIAX is superior to the conventional topical therapy of venous leg ulcers in some cases. Wound dressings provide new therapeutic modalities, being easy to apply and fully efficient, without side-effects.     

Allergic contact dermatitis from modified colophonium in wound dressings

This study concerns a 69-year-old female patient with a longstanding history of venous ulcerations on both lower legs and multiple sensitivities, who developed eczematous lesions with the hydrocolloid dressing Combiderm (Convatec Ltd., a Bristol-Myers Squibb division, Ickenham, Middlesex, UK). Epicutaneous tests were positive to this dressing and to a modified colophonium derivative, i.e. glyceryl rosinate, however not to the unmodified colophonium from the standard series. A review of the literature showed several case reports about sensitization to similar hydrocolloids being distributed under various brand names in different countries and which contain the pentaerythritol ester of the hydrogenated rosin as the tackifying agent. Some of the patients described did, while others did not, react to colophonium but only to a modified derivative. In our patient, the reaction to glyceryl rosinate most probably represent cross-sensitivity with the modified colophonium derivative used in Combiderm, the presence (but not the exact nature) of which was showed by the company. In patients where allergic contact dermatitis from hydrocolloid dressings is strongly suspected and colophonium tests negatively, patch testing to modified colophonium derivatives should therefore be performed. As the complete composition of wound dressings is most often unknown, we urgently advocate legal requirements for labelling of those and in fact all medically used devices.