Dressings for Acute and Chronic Wounds: Title and subTitle BreakA Systematic Review FREE

Wounds are a major cause of morbidity and impaired quality of life and take up substantial health care resources in developed countries.¹ Each year in the United States, over 1.25 million people experience burns, and 6.5 million have chronic skin ulcers caused by pressure, venous stasis, or diabetes mellitus.²

Since the 1960s, it has been accepted that wound healing is optimal when the wound is kept in a moist environment rather than air dried.^{3 - 4} Occlusive or semi-occlusive dressings that promote reepithelialization and wound closure have been developed for chronic and acute wounds to reduce pain and healing time, absorb blood and tissue fluids, and to be painless on application and removal.⁵ The main occlusive or semi-occlusive dressings are hydrocolloid dressings (HCDs), alginates, hydrogels, foam dressings (FDs), hydrofiber dressings (HFDs), and paraffin gauze and nonadherent dressings. Recent products that are reported to induce angiogenesis or reduce infection are hyaluronic acid (HA) cream or dressings and dressings supplemented with activated charcoal or silver.

Current clinical practice guidelines on the treatment of pressure ulcers, leg ulcers, and diabetic foot lesions and available systematic reviews on the treatment of arterial leg ulcers or surgical wounds have not established a care strategy for each type of wound.^{6 - 12} The choice of ideal dressing remains controversial. We assessed the level of published clinical evidence in support of the efficacy of modern dressings for the care of chronic and acute wounds in terms of complete healing or aspects such as pain, ease of use, avoidance of wound trauma on dressing removal, ability to absorb and contain exudates, and prevention of infection.

Three bibliographic databases were searched from January 1990 to June 2006: MEDLINE, EMBASE, and the Cochrane Controlled Clinical Trials Register. The search was restricted to publications in English and in French. Keywords and selection criteria are given in Table 1. From the list of retrieved titles and abstracts, 1 reviewer (G.C.) selected the studies that used these selection criteria to compare dressings. Case reports and case series were excluded. The reviewer checked study relevance and design using the full versions of the articles. Additional references were retrieved by manual searches.

Wounds were considered to be chronic if time to healing was delayed as a result of impaired tissue repair due to poor oxygenation, malnutrition, or infection.¹³ Chronic wounds include leg ulcers, pressure sores, and diabetic foot ulcers. Acute wounds, however, tend to undergo an orderly and timely repair process that results in sustained restoration of anatomic and functional integrity.¹⁴ They include skin graft donor sites, partial-thickness burns, and posttraumatic and surgical wounds that heal by secondary intention. Studies on deep partial- and full-thickness burns were excluded.

Selected studies were distributed among 19 reviewers who were asked to grade trials using a checklist of items for methodological quality based on a modified version of Sackett's criteria for clinical evidence.^{15 - 16} Each trial was graded by 2 reviewers (G.C. and 1 other reviewer). The 2 modifications to Sackett's criteria^{15 - 16} were as follows: (1) meta-analyses that included level C randomized controlled trials (RCTs) were downgraded from level A to level B, and (2) RCTs were as graded level C if they had 1 or more of the following methodological shortcomings: evaluation of primary outcome was not blind, randomization method was performed incorrectly when it was described, primary and secondary objectives were not clearly defined, objective or subjective measures of dressing performance were not described, and patient groups were not comparable at baseline.¹⁷ The criteria we used for clinical evidence are given in Table 2.

Overall, 2330 studies were retrieved by electronic (n = 2305) and manual (n = 25) searching (Figure). Of these, 141 were considered relevant on the basis of title and/or abstract. However, only 99 full-text articles met our selection criteria (89 RCTs, 3 meta-analyses [1 of the meta-analyses came from 1 of the selected systematic reviews], 7 systematic reviews, and 1 cost-effectiveness study). The references, number of studies by type of dressing, and their level of evidence are given in Tables 3, 4, and 5.^{18 - 64 65 - 108} There were no large RCTs with definitive conclusions (level A trials) for any type of dressing. No level B trials were found for either hydrogels or activated charcoal.

Treatment with HCD resulted in a statistically significant improvement in the complete healing rate of leg ulcers and pressure sores according to 3 meta-analyses^{18 - 20} comparing HCD with paraffin gauze and wet-to-dry gauze dressings (odds ratio, 2.57 [95% confidence interval, 1.58-4.18]¹⁸ ; odds ratio, 2.45 [95% confidence interval, 1.18-5.12], P  = .02¹⁹ ; number needed to treat, 7 [95% confidence interval, 4-16]²⁰ ). However, there was no difference between the healing rates of HCDs and FDs whether for pressure sores or leg ulcers.^{18 ,20} An RCT¹⁰¹ comparing Promogran (Johnson & Johnson, Issy-les-Moulineaux, France) with a nonadherent dressing reported no difference in the complete healing rate of leg ulcers. In brief, for the complete healing of chronic wounds, HCD seems to be more effective than paraffin gauze and wet-to-dry gauze dressings, and there is no difference between FD and HCD in terms of optimizing complete healing rate.

Alginates considerably reduced chronic wound area in full-thickness pressure ulcers when used sequentially with HCD (alginates for the first 4 weeks and HCD for the next 4 weeks compared with HCD alone) and when compared with dextranomer.^{41 ,80} Pain on removal of a dressing, although never evaluated as a primary outcome, was lower for a nonadherent dressing than for HCD in a study of leg ulcers.⁵³ Maceration and odor were also less marked.⁵³ Scores on pain when changing a dressing were lower with an alginate than paraffin dressing in diabetic foot lesions.⁷³

There was no difference in the efficacy of FD, a paraffin gauze dressing, polyethane film, or polyurethane film on donor sites of split-thickness skin grafts.⁵⁷ However, the time to complete healing of these sites was lower with the FD than a silver-coated dressing (SCD), and with an HFD than with paraffin gauze.^{65 ,94} There was no difference in the complete healing rates of HFD and wet-to-dry gauze for surgical wounds.⁹⁵ The HA-impregnated dressings delayed time to complete healing of skin graft donor sites when compared with a glycerine-impregnated dressing.¹⁰² In brief, FD seems to be more effective than an SCD in hastening complete healing of acute wounds, and HFD seems more effective than paraffin gauze.

Pain on dressing change was the primary outcome in 1 study only, which compared HFDs and alginates in surgical wound care and found no difference between these 2 types of dressing.⁷⁸ When pain was a secondary outcome, HFD was superior to paraffin gauze for pain scores in split-thickness skin graft donor sites.⁹⁴ No difference between SCD and FD was found in the incidence of positive bacterial cultures.⁶⁵

According to our systematic review, the methodological quality of most studies of wound dressings is poor (level C). There is little evidence to indicate which dressings are the most effective in chronic and acute local wound care in terms of complete healing, comfort, and prevention of infection. Most studies had several of the following limitations: (1) the number of patients was not based on a sample size calculation performed beforehand; (2) the randomization method was not described; (3) assessment of outcomes was not blinded to treatment or was not completely objective; (4) an intention-to-treat analysis was not always used; (5) assessment of objective or subjective measures of dressing performance was not always clearly described; (6) the study population was heterogeneous, particularly in studies of leg ulcers; (7) whether adjuvant treatments, such as pressure-relieving surfaces for pressure sores or off-loading devices for neuropathic diabetic foot ulcers, were used in each treatment group was not specified; and (8) a small sample size was combined with multiple outcome measures. There is, however, good (level B) evidence to suggest that, for chronic wounds, HCD dressings are better than saline gauze or paraffin gauze for complete healing and that alginates, used either singly or in sequential treatment, are better than other modern dressings in reducing wound area, perhaps because they cause debridement of necrotic tissue. There was no difference between HCDs and FDs in terms of an optimizing complete healing rate, but this does not mean that the products are equivalent because no noninferiority trial has been performed. Only 1 level B study⁷³ found a statistically significant difference for pain reduction in chronic wounds. However, pain was a secondary outcome measure in this study, and the result was statistically significant (P  = .047).

In the case of acute wounds, the studies (level B) provided little useful information. Only 1 study reported a notable difference in healing rate between modern dressings (an HFD) and paraffin gauze or wet-to-dry gauze dressings (modern dressings included alginate, FD, and HCD).⁹⁵ An HA or SCD, when compared with a glycerine-impregnated dressing or an FD, respectively, delayed healing.

No scientific evidence was found for the use of specific dressings in the following cases: hemorrhagic wounds, malodorous wounds, fragile skin, and prevention and treatment of infection. Nor was the evidence sufficient to show a benefit of modern dressings on pain or other performance factors in the dressing of acute or chronic wounds when compared with saline or paraffin gauze dressings (eg, ease of use, avoidance of wound trauma on dressing removal, ability to absorb and contain exudates). In fact, dressing selection by physicians is more about matching criteria such as absence of pain, ease of use, avoidance of wound trauma on dressing removal, and ability to absorb and contain exudates rather than healing properties. Future trials should use validated and standardized tools to measure pain, quality of life, and comfort of use. They should assess healing using clinically relevant objectives, especially the rate of complete healing and time to heal rather than reduction in wound area. Other performance factors should be evaluated independently of any potential effect on healing. Intermediate goals in wound management strategy (ie, primary end points such as complete wound debridement for hydrogel dressings and lowering of systemic infection and prescription of antibiotics for SCDs) might be worth testing. Other end points could be evaluated in specific situations (eg, when there is a need to control bleeding in hemorrhagic wounds or avoid trauma in cases of fragile skin).

In conclusion, available systematic reviews of the value of different types of dressing in the management of acute and chronic wounds provide only weak levels of evidence on clinical efficacy.^{10 - 12 ,18} The review by Palfreyman et al¹² identified 42 RCTs that evaluated dressings for the treatment of venous leg ulcers but found that no dressing was better than any other in terms of number of ulcers healed.¹² In our review, the studies with the best level of evidence underline the potential interest of some modern dressings (ie, use of HCDs and FDs) in optimizing the complete healing rate of chronic wounds, of alginates for the debridement of necrotic tissue from chronic wounds, and of HFDs for hastening the healing of acute wounds. However, our review also stresses the need for more wound care research providing level A evidence. Health care professionals require more detailed recommendations on the use of dressings. A discussion of our review by an expert panel would be useful in achieving professional agreement on the recommended use of dressings.

Correspondence: Olivier Chosidow, MD, PhD, Department of Dermatology and Allergy, Hôpital Tenon, 4 rue de la Chine, 75970 Paris, CEDEX 20, France (olivier.chosidow@tnn.aphp.fr).

Financial Disclosure: Dr Meaume participates in educational programs on Profore multilayer bandaging manufactured by Smith & Nephew and is a co-organizer for an international study on the epidemiology of pain and wounds for Mölnlycke Products. Dr Téot is involved in the following collaborations and partnerships: scientific collaboration of wound dressings with Braun (randomized trial on calgitrol vs alginate in infected wounds) and Kinetic Concepts Inc (KCI) (and the French Ministry of Health) on a medical-economic study of the effects of vacuum-assisted closure (KCI); editorial collaboration with Mölnlycke Products (pain and dressing changes for acute wounds), KCI (on technical considerations of vacuum-assisted closure [World Union of Wound Healing Societies statement]), and Coloplast (on pain management of wounds); and educational partnerships with Smith & Nephew, Johnson & Johnson, and Urgo. Drs Senet and Chosidow are presently involved in building a protocol using Dermagen to treat diabetic foot ulcers; Dermagen is manufactured by Genevrier, a French company that also sells HA-associated dressings.

Accepted for Publication: June 14, 2007.

Author Contributions:Study concept and design: Chaby, Senet, Vaneau, Meaume, Téot, Dompmartin, Denis, and Chosidow. Acquisition of data: Chaby, Martel, Guillaume, Meaume, Debure, Dompmartin, Guillot, and Chosidow. Analysis and interpretation of data: Chaby, Senet, Martel, Guillaume, Meaume, Téot, Dompmartin, Bachelet, Carsin, Matz, Richard, Rochet, Sales-Aussias, Zagnoli, Guillot, and Chosidow. Drafting of the manuscript: Chaby, Senet, Vaneau, and Guillaume. Critical revision of the manuscript for important intellectual content: Senet, Vaneau, Martel, Guillaume, Meaume, Téot, Debure, Dompmartin, Bachelet, Carsin, Matz, Richard, Rochet, Sales-Aussias, Zagnoli, Denis, Guillot, and Chosidow. Statistical analysis: Chaby. Obtained funding: Chaby and Vaneau. Administrative, technical, and material support: Vaneau, Martel, and Sales-Aussias. Study supervision: Chaby, Senet, Vaneau, Guillaume, Debure, Dompmartin, Richard, Rochet, Denis, Guillot, and Chosidow.