Choosing an appropriate dressing for chronic wounds Denise Bell BSc, RGN and Dot Hyam RGN, DipHE Chronic wounds are nonhealing with a sometimes complex aetiology, and dressing such wounds can be difficult and time consuming. Here the authors describe how to select the appropriate wound dressing according to wound characteristics. Figure 1. Cavity wound being packed with Acticoat absorbant antimicrobial dressing Wound healing is a dynamic, complex and highly regulated mechanism of tissue repair and regeneration involving cellular and molecular processes that include cell migration, inflammation, angiogenesis, collagen synthesis and deposition, and re-epithelialisation. 1 Wounds can be classified into two main groups, acute or chronic. Acute wounds are caused by external trauma that triggers a sequence of overlapping phases divided into haemostasis, inflammation, proliferation and maturation. Such wounds usually heal within a predictable time frame. In contrast, chronic wounds do not heal in this timely fashion as the normal processes of healing are disrupted or arrested at one or more points, usually in the inflammatory or proliferative phases. 2 There may be many reasons for this chronicity or nonhealing. The causes may be complex and difficult to resolve or the diagnosis and management may be delayed or inappropriate. 3 The management of chronic wounds tends to be complex and dependent on an accurate assessment; appropriate investigations and a diagnosis are therefore essential when choosing a dressing. Once a wound has been evaluated and any relevant pathology diagnosed and addressed, wound bed preparation (WBP) can remove barriers to healing and stimulate the healing process. The concept of WBP helps clinicians focus systematically on all of the critical components of a chronic www.escriber.com Prescriber 5 June 2007 65
Tissue that is nonviable or deficient Infection and Inflammation of the wound Moisture that becomes imbalanced and must be corrected Edge of the wound not advancing across the wound bed Table 1. TIME: components that can prevent healing nonhealing wound, and uses a process of holistic assessment to identify the underlying cause and address the patient s concerns. 4 While WBP provides an overall view of the wound, the acronym TIME (outlined in Table 1) draws attention to individual components. 5 As individual components, each will have an effect on the ability of the wound to progress. However, one component may dominate over the others at any given point in time. For example, a provide the optimum environment for wound healing a moist environment at the wound dressing interface allow gaseous exchange of oxygen, carbon dioxide and water vapour provide thermal insulation wound healing is temperature dependent impermeable to micro-organisms (in both directions) free from particulate contaminants nonadherent (many products are described as nonadherent but are low adherent) safe to use (nontoxic, nonsensitising, nonallergenic) acceptable to the patient high absorption characteristics (for exuding wounds) cost effective carrier for medicaments, eg antiseptics capable of standardisation and evaluation allow monitoring of the wound (transparent) provide mechanical protection nonflammable sterilisable conformable and mouldable (especially over sacrum, heels and elbows) available (hospital and community) in a suitable range of forms and sizes require infrequent changing products should be left in place for as long as possible Table 2. Characteristics of ideal dressings (after reference 9) sloughy exuding wound with high bacterial load will require debridement of the devitalised tissue to be undertaken; the emphasis will therefore be on tissue as the dominant component preventing healing. Moisture then becomes the dominant component as maintaining a moist, warm environment allows for epithelial migration and contraction to occur. 5 Focussing on the dominant component of TIME (a process that requires regular reassessment to ensure optimum wound care is given) can assist in selecting appropriate wound care products, as there is less chance of multiple dressing choices being employed. Choosing the appropriate dressing There is a huge variety of dressings to choose from, including those that protect, debride, stop bleeding or remove exudate. The effectiveness of a given dressing has to be evaluated in the context of the underlying aetiology and the treatment regimen as a whole, incorporating the frequency of the dressing change and the clinician s time. No single dressing is suitable for the management of all wounds, and there are few dressings that are ideally suited for the treatment of a single wound during all stages of the healing process. Table 2 summarises the characteristics of an ideal wound dressing. Dressings should be selected according to the specific characteristics of the wound. Considering the type of wound requires an understanding of the wound aetiology, the underlying medical condition, the wound history and treatment to date. The location and appearance of the wound itself and the condition of the surrounding skin, the presence of necrotic, sloughy tissue and infection, and the depth of the wound are all to be considered. The effective management of exudate with appropriate dressings is essential as too much or too little exudate influences the process of wound healing, and the amount and viscosity of exudates should therefore be examined carefully. Dressings are also required to manage the unpleasant visual and malodorous aspects of wound exudate. 6 Other factors to consider when selecting a dressing include: the environment in which the patient receives care, the characteristics and cost-effectiveness of the actual dressing and patient compliance. Patient compliance may be enhanced when a dressing is chosen collectively with the patient. Table 3 is a visual reference guide to product selection according to wound characteristics, and Table 4 shows wound dressings grouped according to type, describing their presentation and giving a summary of their advantages and disadvantages. Not all products within a group have the same physical or biochemical properties, so the performance of individual products will vary. The management of wounds places a huge burden on healthcare resources, and although accurate data are difficult to obtain, studies have calculated the cost to the NHS to be around 1 billion per year. 7 In the current climate of financial restraints on the NHS, clinicians are under pressure to make cost savings, and wound dressings is an area where considerable savings are expected to be made. However, making cost savings must take into account not just unit cost of the product but also its cost-effectiveness, so must include cost of treatment, health professionals time, clinical outcomes and impact on patient quality of life. 8 66 Prescriber 5 June 2007 www.escriber.com
Clinicians require an understanding of the range of modern wound dressings that are currently available. Appropriate dressing selection should aid healing and improve patient outcome, and effective wound management has the potential to reduce the financial burden that wound dressings place on the NHS. References 1. Clark RA. Basics of cutaneous wound repair. J Surg Onc 1993;19:693-706. 2. Lazarus GS, Cooper DM, Knighton DR. Definitions and guide lines for assessment of wounds and evaluation of healing. Arch Dermatol 1994;130(4) :489-93. 3. Harding K. Wound bed preparation; lessons from chronic and acute wounds. In: Falanga V, ed. New concepts in wound bed preparation. Germany: Springer-Verlag, 2003. 4. Schultz GS, Sibbald RG, Falanga V, et al. Wound bed preparation: a systematic approach to wound management. Wound Repair Regen 2003; 11(Suppl 1):S1-28. 5. Sibbald RG, Williamson D, Orsted HL, et al. Preparing the wound debridement, bacterial balance and moisture balance. Ostomy/Wound Management 2000;46(11):14-35. 6. Cutting KF. Exudate: composition and function. In: White RJ. Trends in wound care. Wiltshire: MA Healthcare, 2004. 7. Harding KG. The future of wound healing. In: Leaper DJ, Harding KG, eds. Wounds: biology and management. Oxford: Oxford University Press, 1998. 8. Price P. The challenge of outcome measures in chronic wounds. J Wound Care 1999;8(6):306-8. 9. Morgan DA. Formulary of wound management products. A guide for health care staff (8 th ed). Surrey: Euromed Communications Ltd, 2000. Denise Bell is a leg ulcer nurse practitioner in the Department of Tissue Viability/Dermatology at Bristol Royal Infirmary, and Dot Hyam is a clinical specialist with Smith & Nephew Healthcare, Hull Necrotic wounds rehydrate and debride black, dry eschar hydrogels hydrocolloids Sloughy wounds rehydrate /absorb excess exudate and debride slough hydrogels to hydrate + foam as secondary dressing alginates or cadexomer iodine for wet slough to absorb and facilitate debridement + foam as secondary dressing Infected wounds local infection: consider silver dressings, cadexomer iodine or honey dressings; choice of product will be influenced by depth of wound, level of exudate, odour and pain; dressings containing charcoal to reduce odour systemic antibiotics when clinical signs and symptoms of infection are present Granulating wounds manage exudate to maintain a moist environment; prevent infection alginates/hydrofibre for cavity wounds + foam, film or hydrocolloid for secondary dressing foams/film + pad for superficial wounds Epithelialising wounds maintain moist environment; protect and prevent infection foam dressing Surgically closed wounds absorbent perforated film dressing Diabetic foot wounds aim to remove excess fluid; do not use occlusive dressings hydrocolloids not recommended alginates, foams Table 3. A visual guide to product selection according to wound characteristics Ischaemic wounds keep these wounds dry occlusive dressings not recommended www.escriber.com Prescriber 5 June 2007 67
Dressing type Characteristics/composition Advantages Disadvantages Vapourpermeable films polyurethane film with adhesive backing transparency allows visual inspection of the wound conformable, suitable for superficial, epithelialising, low-exuding wounds or protection of primarily closed wounds; may decrease pain at wound site; can be used as a secondary retention dressing; also used to prevent friction and shear damage excessive exudate may cause maceration; may cause stripping of epithelium when removed Non/lowadherent wound contact layer knitted viscose primary dressing; may be coated with silicone, triglycerides, soft paraffin wound contact layer allowing exudate to pass through to secondary dressing; can reduce pain and help maintain moist environment; suitable for lightly exuding wounds although some are suitable for moderate/heavily exuding wounds with wear time of up to 7 days some dressings will adhere to wound if allowed to dry out or not changed frequently, causing pain and tissue damage; requires secondary dressing Absorbent perforated film absorbent perforated plastic filmfaced dressing; some have adhesive border suitable for superficial, lightly exudating wounds or primarily closed wounds some are low adherent rather than nonadherent; may cause skin damage if used on highly exuding wounds Hydrogels available as sheets with or without adhesive border or amorphous gels; high water content able to donate fluid as well as having limited absorption properties used to rehydrate eschar and slough to facilitate autolytic debridement; nonadherent; soothing effect that helps reduce pain; aids creation and maintenance of moist environment; amorphous gels can be used in cavity wounds may cause maceration if used on highly exuding wounds; amorphous gels require secondary dressing; need frequent application Hydrocolloids available as flat sheets, anatomically shaped, with or without adhesive border; also hydrocolloid fibre available; caroxymethylcellulose is most common absorptive ingredient; some contain pectin promotes autolytic debridement of necrotic tissue, absorbs low to moderate levels of exudate, stimulates granulation, and reduces pain; waterproof and conformable; may be left in place for 7 days; hydrocolloid fibre forms a gel on contact with exudate, which allows pain-free removal; suitable for shallow and cavity wounds high levels of exudate may lead to maceration; overgranulation can also occur; not recommended if anaerobic infection is suspected; adhesive hydrocolloids may cause skin trauma on removal if used on fragile friable skin; may have unpleasant odour upon removal; hydrocolloid fibre dressing requires secondary dressing Alginates manufactured from different varieties of seaweed; alginates rich in mannuronic acid form soft flexible gels, whereas those that are rich in guluronic acid form firmer gels; available as flat sheets, ribbon or rope suitable for shallow or cavity wounds; alginates are best suited for granulating wounds with medium to high levels of exudate will not debride dry eschar; do not apply to wounds with low levels of exudate as there is a risk of drying the wound bed may be painful to remove; not the best choice of dressing if infection is present; requires secondary dressing Table 4. Properties of wound dressings with their advantages and disadvantages www.escriber.com Prescriber 5 June 2007 69
Dressing type Characteristics/composition Advantages Disadvantages Foam polyurethane foams with or without adhesive border; may have silicone, gel, or film nonadhesive wound contact layer; some are waterproof and bacteria proof; range of sizes and anatomical shapes available; some can be used for cavity wound packing used for the management of granulating/ epithelialising wounds; capable of managing low to high levels of exudate depending on product selected; conformable, aids debridement and maintains moist environment; can be used as secondary dressing over wound packing; most can be left in situ for up to 7 days depending on exudate levels do not use on dry wounds Cadexomer iodine cadexomer, a modified starch, macrogol impregnated with iodine (0.9% w/w) to form a paste or iodine-impregnated cadexomer hydrophilic beads as ointment or powder use to debride slough, absorb exudate and reduce bacterial load; provides a sustained release of iodine; effective against a broad spectrum of Gramnegative and Gram-positive organisms, fungi, yeasts, protozoa and viruses; dressing requires changing usually 2-3 times per week or when opaque in appearance; dressing residue is biodegradable requires secondary dressing; maximum single application of 50g; weekly maximum must not exceed 150g; treatment duration must not exceed 3 months; regular use should be avoided in patients with thyroid disorders or those receiving lithium therapy; must not be used in patients with known or suspected iodine sensitivity; may cause stinging/burning sensation when first applied Silver a wide variety of dressings impregnated with silver are available: foams, alginates, films, mesh, hydrocolloids and gels effective antibacterial against a broad spectrum of Gram-negative and Grampositive organisms including MRSA, fungi and viruses; provides sustained release over several days depending on product selected, wear time came be up to 7 days may require secondary dressing; can cause transient skin staining; stinging or burning sensation has been reported with some products; should not be used in patients with known sensitivity to silver Honey a variety of dressings available impregnated with pure honey or combined with other ingredients; alginates, mesh and hydrogels available as well as gels and ointments: some have adhesive border effective antibacterial action with debriding and anti-inflammatory properties; acts as a stimulant for the growth of new blood capillaries, fibroblasts and epithelial cells not recommended in patients with known sensitivity to bee venom; monitor patients with diabetes as glucose and fructose can be absorbed from an open wound; may require more frequent dressing changes as honey is diluted increasing exudate levels; may cause stinging/burning sensation on application; may require secondary dressing Charcoal contains activated charcoal; available as a wound contact layer, with low-adherent surface or multilayered with film backing, absorbent pad and alginate wound contact layer used in the management of discharging, purulent and contaminated wounds complicated by bacterial infection and offensive odour; can be used as primary dressing or secondary dressing over packing; frequency of dressing change will depend on exudate levels some dressings do not maintain a moist environment over the wound; will require dressing tape to hold in place; many of the Gram-negative anaerobes are the primary cause of wound odour; the use of a topical antimicrobial such as iodine, silver or honey may be more effective for their eradication and, therefore, elimination of malodour Table 4. Properties of wound dressings with their advantages and disadvantages (cont.) 70 Prescriber 5 June 2007 www.escriber.com