Wound Basics
CE: Wound basics: Types, treatment, and care
With hundreds of wound care products on the market, would you know which ones to choose for a patient? Here's a review that will help you decide.
August 01, 2008 By Linda Snyder, RN, WCC
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After reading the article you should be able to:
1. Compare and contrast between the different choices available to treat wounds.
2. Differentiate between the six main categories of wounds.
3. Develop a plan of care for a patient with a wound.
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Originally Posted August 2008
By LINDA SNYDER, RN, WCC
LINDA SNYDER is a clinical case manager, wound care consultant, and chair of the education committee at Keystone Home Health Services in Wyndmoor, PA. She is certified in skin and wound care management by the National Alliance of Wound Care, Glendale, WI. The author has no financial relationships to disclose. CONTRIBUTING EDITOR: Kathleen A. Moore, RN, BS.
Wound care is a billion-dollar industry in the United States, where chronic or complex wounds will soon affect as many as 7 million people.1 Wounds are caused by one or a combination of factors, and their management traverses all healthcare settings, from acute care hospitals to the home. The treatment of chronic wounds, in particular, places a significant burden on healthcare spending.1
Several factors determine how a wound is treated, including the wound's etiology, the amount of exudate, the anticipated frequency of dressing changes, and cost. Here, I'll review the main types of wounds, their causes and physical characteristics, and the dressing choices available for treating them.
How to classify wounds
There are six main categories of wounds: surgical, trauma, diabetic, venous, arterial, and pressure. These categories, however, can overlap. The easiest wound to identify is the surgical wound, in which primary closure of an operative site, by way of sutures or staples, is incomplete. Incisions, graft donor sites, and excisions are considered acute surgical wounds. Dehisced or infected surgical sites are classified as chronic.2 In each case, the primary goal is to maintain a moist wound environment so that granulation tissue can form and help close the wound, or until a form of secondary closure, such as a skin graft, can take place.
Traumatic wounds are caused by an outside force and include skin tears, cuts, and punctures. They usually heal with minimally invasive treatment. Those caused by severe trauma, however, may require surgical repair before they heal.
Diabetic ulcers typically begin with injury or irritation that the patient doesn't feel because diabetic neuropathy diminishes sensation. The ulcer may result from a single traumatic event, such as stepping on a sharp object, or from repeated damage caused by, say, tight shoes or hot water bathing.1
The majority of diabetic ulcers form on the lower extremities, often on the plantar aspect of the foot. To promote healing and prevent extreme complications, such as infection and amputation, it's imperative that the patient's diabetes be managed appropriately; if it's not, uncontrolled blood glucose levels will interfere with healing.
Arterial wounds are caused by ischemia. Like diabetic ulcers, they usually affect the lower extremities. Pressure areas, such as toes and metatarsal and malleolar locations, are commonly affected. In some instances, trauma, such as stubbing a toe, precipitates their development. Claudication, pain at rest, and gangrene are typical findings. Because the underlying problem is arterial insufficiency, treatment, to be effective, should include revascularization, such as bypass grafting, to improve circulation in the extremity.2
Lower legs also are targets for venous, or venous stasis, ulcers. This type of wound is caused by poor venous return, which may be due to weakened leg valves; blockages, such as deep vein thrombosis (DVT); or inadequate venous pump mechanisms.
The ulcers form when venous blood pools in the lower legs causing fluid leakage from the vessels into the surrounding tissues, decreasing circulation to the skin. Treatment includes compression therapy to facilitate the return of blood to the heart.
A sixth type of wound is the pressure ulcer, which may result from pressure alone or from pressure combined with friction. In the immobile, malnourished, or dehydrated patient, this type of ulcer forms quickly, typically over bony prominences. The heels, the sacrococcygeal area, and over the trochanters are the most typical areas for these wounds. The use of turning schedules and support surfaces to redistribute the patient's weight can reduce the occurrence and severity of these wounds.3
Pressure ulcers are the only wounds that you should stage. The National Pressure Ulcer Advisory Panel (NPUAP) has updated its staging table to better describe the wound appearance and to include suspected deep tissue injuries. For more information on the prevention, staging, and pressure ulcer treatment, consult the NPUAP Web site at www.npuap.org.
Venous, arterial, and diabetic ulcers, because they all affect the lower extremities, often are difficult to distinguish. The table below provides a basic description of each. Bear in mind, though, that a wound may have a mixed etiology—or more than one cause—particularly in patients with multiple co-morbidities.
Choosing an appropriate dressing
Wound management is multidimensional. Addressing a wound's underlying causes, such as diabetes, tissue ischemia, and/or venous insufficiency, is an essential treatment component. Ensuring that a patient's nutritional intake is sufficient to support wound healing is equally important.
Another critical ingredient in wound management is the right dressing. Today's market offers a vast selection of products, from simple gauzes to silver-containing dressings to negative pressure therapies. Admittedly, choosing the best option for your patient, while bearing cost in mind, can be daunting. When selecting a dressing, consider the following general recommendations:
- Keep the wound moist. Maintaining a moist wound environment promotes healing and is considered the standard of care.4 A moist wound heals twice as quickly as a dry one.5 In fact, air-drying, or exposing a wound to air, is counterproductive to healing. Keeping the wound moist also provides it with a barrier against invasion by infectious organisms.1 Infection delays wound closure, complicates treatment, and increases the cost of care.
- Avoid standard wet-to-dry dressings. This type of dressing is a poor choice for maintaining a healthy wound bed. It actually can be detrimental to healing.5 While the wet-to-dry dressing may be an appropriate short-term method of mechanical debridement, it's not the dressing of choice for most wounds.
- If it's wet, dry it; if it's dry, wet it. This means that a wound with heavy exudate will need a more absorptive dressing, such as a foam or alginate, while a dry wound will require rehydration with a hydrogel or an occlusive dressing, such as a hydrocolloid. These four types of dressings are discussed below.
Alginates. Derived from seaweed, these highly absorptive dressings are soft, nonwoven, and nonadhesive, and conform to the shape of the wound.6 When in contact with drainage, they form a gel. Alginates are most useful for wounds with heavy exudate. Don't use them for dry or eschar-covered wounds, because they won't form a gel and may stick to the wound, causing tissue trauma when you remove them. Some alginates assist with debridement of nonviable tissue, and some contain silver, whose broad-spectrum antimicrobial activity minimizes bio-burden—the number of bacteria present on the product. If a patient has a silver dressing, you may need to remove it before magnetic resonance imaging (MRI).
Alginates come in sheets that you can cut to size. They also come in rope form, which is especially good for areas of undermining or tunneling. For large wounds, though, alginates can be an expensive choice.
When using an alginate, you'll need to cover the wound with a secondary dressing to hold the product in place and to protect the wound from outside contaminants. Leave the alginate in place for one to three days, until it begins to gel and shows evidence of breakthrough drainage. Thoroughly irrigate the wound with sterile normal saline solution before reapplying the alginate.7
Foams. Typically polyurethane-based, this type of dressing is nonadhesive and comes in various sizes, shapes, and degrees of thickness. With their small to moderate absorptive capacity, foam dressings provide thermal insulation and help keep the wound moist. They may be used as a primary or secondary dressing, to promote autolytic debridement, and to inhibit hypergranulation.6 When using a foam dressing, make sure it's one to two inches larger than the wound; you can leave it in place for up to seven days.
Hydrocolloids. Either semi- occlusive or occlusive, hydrocolloid dressings contain hydrophilic colloidal particles in an adhesive compound laminated to a flexible wafer. Like foams, they come in numerous sizes, shapes, and levels of thickness. Some have tapered edges that are less likely to curl up.6
Hydrocolloids have minimal absorptive capabilities. They help keep the wound moist and promote autolysis of necrotic areas. Don't use them on wounds that are infected or have heavy exudate. To avoid damaging fragile skin by removing the dressings too frequently, keep them in place for as long as possible, but no longer than seven days.7
Hydrogels. Available as gels, sheets, or gauze impregnated with various percentages of water, hydrogels are hydrophilic polymers with few absorptive properties. They add moisture to the wound bed and are nonadherent, and they're used mainly for dry and minimally exudative wounds. If stored in the refrigerator, they can provide cool relief to painful wound sites.7
Negative Pressure Wound Therapy (NPWT), such as vacuum-assisted closure (VAC), is an option for treating wounds that are draining heavily, failing to heal, or healing slowly. NPWT applies subatmospheric pressure to the wound through the use of special foam dressings occlusively sealed and connected to a pump and collection chamber. NPWT is useful in removing exudate and debris, promoting blood flow, hastening tissue granulation, and encouraging the contracture of wound edges. It's especially helpful in treating deep, cavernous wounds; the foam fills in dead space, and this can enhance closure of tunneling and undermined areas.2
Debride the wound first
Before you apply the dressing of choice, make sure that nonviable tissue, such as slough, eschar, and fibrin, have been debrided. Eschar that's dry, hard, and stable need not be removed, however, unless signs of infection are present—redness, pus, fluctuance (bogginess or mushiness), wound edge separation with drainage, for example.2 Whenever you suspect infection, notify the physician or surgeon, the nurse practitioner, or the wound care specialist; wound cultures and/or antimicrobial therapy may be indicated.
Debridement is accomplished in one of several ways. Using a scalpel, scissors, or a curette, a trained practitioner can physically remove the devitalized tissue—a procedure known as surgical, or sharps, debridement. This is the quickest and most direct method, but it's the most painful and has the greatest potential for complications, such as hemorrhage.
A second method, mechanical debridement, uses a means of external force, such as pulsed lavage or wet-to-dry dressings, to dislodge and remove debris and necrotic tissue from the wound surface.2 Pulsed lavage with suction requires an experienced clinician and a pressure setting below 15 psi. Higher pressures can drive bacteria into the underlying tissues.2 With wet-to-dry debridement, moistened gauze placed in the wound bed dries and adheres to the necrotic tissue; when you remove the dried gauze, you tear off the dead tissue with it. Unfortunately, you damage healthy tissue, too, and this may cause pain and bleeding.
Another form of debridement is autolytic, which uses the body's fluids to loosen and liquefy necrotic tissue. Autolytic debridement uses occlusive dressings, such as hydrocolloids or transparent films, and can be used on any type of wound. Although it's the slowest method of debridement, it's virtually pain-free and requires minimal technical skill. When using autolytic products, watch that the fluid that collects beneath the dressing doesn't macerate the surrounding tissue.
Enzymatic debridement uses topical preparations to speed up the body's autolytic process. It's most effective on large wounds and can be facilitated by cross-hatching thick areas of eschar.8 The most common preparations for enzymatic debridement are collagenase, which is found in Santyl, and papin-urea combinations, such Accuzyme and Panafil.
When applying the dressing
Before dressing the wound, clean it with sterile saline or a commercially prepared cleansing spray, and then perform a wound assessment. The Wound Care Education Institute (WCEI) recommends that you document the following: the wound's location, dimensions, and appearance; the presence of granular, necrotic, or epithelial tissue; the type (sanguineous, serous, purulent, or serosanguineous), amount, consistency, and odor of the exudate; the condition of the skin surrounding the wound (whether there's maceration, erythema, induration, edema, etc.); and conditions that may impede healing, such as limited mobility, malnutrition, incontinence, other medical conditions, or noncompliance with prescribed treatments.7
After the assessment, protect the healthy skin by applying a barrier cream or wipe around the wound, and follow the manufacturer's recommendations for the dressing. Monitor and document the patient's response to the dressing application—whether he experiences discomfort, for instance. Dispose of used material in the proper waste receptacle, and wash your hands.
Wound care that's evidence-based, addresses a wound's etiology, and incorporates the appropriate tools can expedite healing, saving you time, your facility money, and your patient unnecessary discomfort. Knowing why wounds develop and how various dressings work will help you navigate the maze of treatment options and choose ones that best suit your patients' needs.
REFERENCES
1. Advanced Medical Technology Associates. Advanced wound management: Healing and restoring lives. 2006. https://www.advamed.org/NR/rdonlyres/8D8348E8-811D-48A9-8737-61D91060DDAD/0/june2006_woundmanagement.pdf (23 Aug 2007).
2. Krasner, D. L., Rodeheaver, G.T., & Sibbald, R.G. (Eds). (2007). Chronic wound care: A clinical source book for healthcare professionals (4th ed.). Malvern: HMP Communications.
3. Wound, Ostomy, and Continence Nurses Society. (2003). Guideline for prevention and management of pressure ulcers. Glenview, IL: WOCN.
4. Spear, M. (2008). Wet-to-dry dressings: Evaluating the evidence. Plast Surg Nurs, 28(2), 92.
5. Armstrong, M. H., & Price, P. (2004). Wet-to-dry gauze dressings: Fact and fiction. Wounds, 16(2), 56.
6. Taylor, B. A. (2003). Selecting wound healing products. Advance for Nurse Practitioners, 11(5), 63.
7. Wound Care Education Institute. (2006). Skin and wound resource manual. Aurora, IL: WCEI.
8. McCallon, S. (2007). Enzymes for wound debridement and healing. Extended Care Product News, 120(6), 30.