Issue: Volume 65 - Issue 4 - April 2019 ISSN 2640-5245
In the topical management of open wounds, dressing selection is driven by a thorough assessment to determine what is needed by addressing the tissue type, the presence or threat of bacterial load, and the wound location. The primary concern is the amount of exudate and what periwound skin protection is necessary — hence, the title of this paper: the wound exudate hokey pokey. That’s what it’s all about.
Packing. As we consider the choice of dressing to meet the environmental needs of the wound, we must maintain a moist wound environment while filling any space with a material that can adequately and efficiently absorb exudate to prevent its spread onto intact skin. Spaces such as undermining and tracts should be loosely packed with enough material to make intimate contact with the wound without overpacking that could potentially cause trauma, especially if the patient may lie or sit on the area or if compression wraps will be added. If the bacterial load is a consideration, most packing and covering materials are available with choices of antimicrobial agents to manage bacteria once absorbed into the dressing.
Compression. Edema is a significant contributor to excessive wound exudate. Reducing edema will improve efforts to manage excessive amounts of exudate. Compression is the standard of care in the presence of adequate blood flow to address edema in cases of chronic venous insufficiency (CVI) and lymphedema caused by dependent positioning or on the trunk related to the wound or inflammation. However, in lower extremity wounds not related to CVI or lymphedema, consider the use of some level of compression or edema management to contribute to reducing the exudate. For both lower extremity as well as trunk wounds, negative pressure wound therapy may be an adjunct to obtain an initial reduction in edema (and therefore exudate) to a more manageable state.
Dressing Categories for Exudate Management
Gauze. Woven gauze is generally not recommended as a packing material for open wounds. The use of wet-to-dry dressings, although still commonly used, will not adequately contribute to exudate absorption; in fact, it may cause local trauma and pain at the wound site. With that said, a bulky cotton gauze roll may be loosely packed into larger spaces as a temporizing measure until other dressings are available or other procedures (such as surgery) are considered. Packing ribbons, either plain or impregnated with iodophor or hypertonic saline, may be useful in packing narrow tunnels or tracts to facilitate movement of exudate into the secondary dressing. Care should be taken to extend the packing ribbon well beyond the packed area in order to enable complete removal and prevent loss of the material into the depths of the wound.
Calcium alginates. Calcium alginates are composed of calcium/sodium salts of alginic acid. Alginates are derived from a variety of seaweed sources. They form a moist gel through a process of ion exchange with the wound exudate. They are primary dressings placed in contact with the wound bed and are indicated for pressure, arterial, and venous wounds; diabetic ulcers; and postoperative and trauma wounds. They conform to the wound surface, creating a moist wound environment, and can be used to tuck, pack, or fill uneven surfaces, tunnels, and undermining. Alginates support autolytic debridement and are painlessly removed when moist, or can be remoistened with saline irrigation, should they dry out. Alginates require a secondary absorptive dressing to soak up drainage not absorbed by the alginate, to hold the dressing against the wound bed, and to protect the wound from outside contaminants. They are available in various sizes and conformations such as sheets, pads, and ropes. Alginates have hemostatic properties and may assist in stopping punctate bleeding. Alginate dressings are contraindicated for wounds that are dry or have minimal exudate or for third-degree burns.
Gelling fiber dressings. Similar in function to calcium alginate dressings, gelling fiber dressings are absorbent wound covers that are typically composed of sodium carboxymethyl cellulose, strengthening cellulose fibers, and other blended superabsorbent materials. As wound fluid is absorbed into the dressing, a gel forms, which assists in maintaining a moist environment and protecting the periwound skin. These dressings vary among manufacturers and may include additives such as chitosan, which enhances hemostasis. These dressings are available in a variety of sizes and in pads and ropes. They also require a secondary dressing.
Foams. Foams are versatile dressings that are indicated for absorbing moderate to copious amounts of fluids on partial- and full-thickness wounds; they also are now commonly used as prophylactic protection over bony prominences. These dressings are generally polyurethane or polyvinyl alcohol foam and may be used as primary or secondary dressings. The dressings feature small, open cells capable of wicking drainage away from the wound through their hydrophilic properties, retaining exudate in the upper layers of the dressing or allowing it to pass through to another absorbent pad to protect the wound bed and the periwound skin. Foam dressings may be adhesive or nonadherent, with or without borders, and many are available with silicone adhesion. Some advanced foams may be used in wounds with higher levels of exudate; these dressings have absorbent particles suspended within the dressing, multiple layers, larger pores at the wound interface to absorb more viscous exudate, and additional cuts to enhance comformability and increase surface area for absorption. One specialized foam dressing also releases surface active agents onto the wound bed to facilitate cleansing.
Superabsorbent and specialty absorbent dressings. A growing category of dressings, superabsorbents are just what their name implies — dressings made from a variety of different layers of fibers, particles, cellulose, and other materials that rapidly wick and hold higher amounts of wound exudate and lock it into the dressing or pass it through to a secondary dressing. They may be made from fibrous materials or foam combinations, enabling longer wear time and reducing the frequency of dressing changes.
Conclusion
To summarize, exudate management is a key consideration for dressing selection. When assessing the degree of absorption that will be needed, consider the amount and character of the exudate at the dressing change. Also consider the periwound skin condition: is additional protection (such as polymer skin preparations, cyanoacrylates, or a barrier ointment) necessary until the exudate is under control? Close and accurate scrutiny at each dressing change will allow the clinician to make dressing decisions that will meet the needs of the wound. Wounds are dynamic and will change along the healing trajectory. Modern dressings allow us to alter the treatment plan to accommodate those changes.
