Appropriate wound bed preparation begins with comprehensive assessment and consists of removing local barriers to healing.

       Editor’s note: The first part of this article ran in the July/August issue of ECPN and can be accessed online at www.extendedcarenews.com.

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linicians are advised to never debride a stable, nonfluctuant heel eschar—nor those wounds that appear dry, noninfected, nonfluctuant, ischemic, or dry and gangrenous—until vascular status and perfusion to the extremity is improved.¹ At minimum, a patient with a lower-extremity ulcer must have an ankle-brachial index (ABI) assessment performed during the comprehensive clinical assessment when debridement is being considered.² Additionally, atypical wounds, such as Pyoderma gangrenosum or calciphylaxis, or wounds of unknown etiology should not be debrided in an extended care setting due to the risk of pathergy.
       Methods of debridement, listed from the least to most invasive, include: autolytic, biologic, mechanical, enzymatic, conservative sharp, and surgical. Each has advantages and disadvantages, and the clinician must determine which is appropriate while considering the overall condition of the patient and the goals in the plan of care. Of significant concern is what the patient can reasonably tolerate. If pain is a factor, enzymatic or sharp debridement may not be appropriate, although it could be the fastest method of debridement. If the patient is on an anticoagulant, clotting may be inhibited if bleeding occurs during the sharp debridement.
       Surgical debridement is the fastest and most reliable method of debridement, but it not be a viable choice as some extended care patients are not candidates for any surgical procedures or anesthesia. Cost may be a factor, as enzymatics can be expensive if not covered by an insurance plan. (See Table 1 for a summary of debridement options and the advantages and disadvantages of each.) Other advanced dressings like polyacrylate gel absorbents provide for moist wound healing with Ringer’s solution and pain-free debridement by absorbing and irrigating simultaneously with simple 24-hour dressing changes. Recent literature has shown that the product may be effective in reducing wound bioburden by interfering with biofilm.³

Table 1

       Typically, more than one method of debridement is utilized in the ongoing process of wound bed preparation. Autolytic debridement may be used to soften up an eschar on a patient who cannot tolerate enzymatics, followed by conservative sharp debridement. Weekly sequential conservative sharp debridements performed at the bedside may follow daily application of enzymatic debriding agents. In a particularly dirty wound, pulsed lavage may prepare the site for surgical debridement. Whichever method is selected, a reassessment of the wound should be performed at each dressing change and an alteration in the debridement made to accommodate the changing wound bed status.

Wound Bed Preparation: Management of Bacterial Burden

       It is well agreed upon that some levels of bacteria are present in all wounds. Variables that can affect the bacterial burden in a wound and thereby increase the risk of infection include the host resistance, amount of necrotic tissue, number of microorganisms, and bacterial virulence.⁴
       Contamination refers to nonreplicating bacteria that do not contribute to impaired wound healing, and colonization refers to replicating bacteria without a host reaction.⁵ Critically colonized wounds exhibit increased serous drainage, increased pain and tenderness, friable granulation tissue, and delayed healing. A fine balance exists, and it is often difficult in clinical practice to ascertain when this balance tips and causes impaired wound healing. At this point, clinical management goes back the basics, including a thorough cleansing, the removal of devitalized tissue and debris, and a consideration of topical antimicrobial agents. The selection of dressing may also change to improve exudate management. The Agency for Healthcare Research and Quality (AHRQ) guidelines suggest not using swab cultures to determine infection, as these will only detect the surface bacteria.¹ The gold standard to determine wound infection are tissue cultures, but they are rarely obtained in extended care settings.
       A wound is considered infected when the bacteria have invaded the tissue and replicated enough to cause injury to the host and impair healing.⁴ Clinical signs include erythema, heat, edema, and pain. Purulent, foul-smelling exudate may also be present. Although inflammation is a normal response for the first 5–7 days after injury, acute infection is an exaggerated inflammatory response. At this point, the management of the wound is the same as it would be for a critically colonized wound, with the possible addition of systemic antibiotics in addition to the already used topical antimicrobials, such as ionic silver or polyhexamethylene biguanide (PHMB),⁶ if the signs and symptoms of systemic infection are present. These signs may include extensive and advancing erythema, cellulites, elevated body temperature (often absent in the elderly), elevation in white blood cells (WBCs) and in diabetics, and elevated blood glucose levels. Some patients may need hospitalization for treatment of infection and/or septicemia.
       Persistent nonhealing wounds may be chronically infected with the loss of the normal inflammatory response. The WBCs can no longer do their job, and disorganized collagen is produced by the fibroblasts. Granulation tissue is altered and discolored, and there is less efficient angiogenesis or growth of new blood vessels. Epithelialization is impaired, and a generalized failure of wound healing is observed. Along with the above interventions, management may include a tissue or needle biopsy, evaluation for possible osteomyelitis, and surgical debridement. An interdisciplinary team approach is warranted to include both patients and their families in the decision for the next step.

Wound Bed Preparation: Exudate Management

       Selection of the most appropriate dressing for a wound can overwhelm some clinicians. Because there are more than 2,200 wound products to choose from, the task can be daunting. Some products manage exudate and some manage moisture and provide hydration. The goal of exudate management is to maintain an optimally moist healing environment to allow for cell migration. Interventions are focused at maintaining a balance of moisture without over-saturating or drying out the wound bed. Again, good clinical assessment is needed to select the proper dressing to promote wound healing, keeping in mind the holistic approach as well as which products are available.⁷
       The enemy of a wound is desiccation, which leads to eschar, destroys healthy tissue, promotes infection, and prevents healing. When a wound bed is too dry, the migrating epidermal cells have to travel underneath the dryness to find moisture. For minimally dry to minimally exudating wounds, choose occlusive dressings, such as films or hydrocolloids, to promote granulation tissue formation and concurrent autolytic debridement. Hydrogels (amorphous, sheet, and gauze-impregnated) may also be used in combination with these dressings, although they have minimal absorptive qualities.
       For moderately exudating wounds, dressing choices include alginates, collagens, composite dressings, foams, or specialty absorptive dressings. Some wounds meet criteria for negative pressure wound therapy (NPWT), in which the exudate is contained in a canister. The goal again is to wick away excess moisture, maintaining a moist wound bed and promoting red, beefy granulation tissue.
       Excessive exudate from chronic wounds is known to have a deleterious effect on wound healing. The higher levels of matrix metallaproteases (MMPs) degrade the extracellular matrix, keeping the wound in the inflammatory phase.⁸ This excessive exudate also selectively prohibits proliferating cells, which stall wound healing.
       When wounds are highly exudative, one or a combination of dressings are appropriate. These include alginates, foams, collagens, composites, and gauze-based dressings. Periwound maceration (ie, the softening of the skin surrounding the wound) is the result of excessive exudate leaking onto the surrounding intact skin. Protection of this skin using a barrier cream or solution is essential to avoid additional tissue injury in the area.
       Antimicrobial dressings are indicated for wounds with minimal, moderate, or heavy exudate, depending on the dressing selected. The choices (eg, ionic silver dressings, cadexomer iodine, and PHMB-based dressings engineered to control bacterial and other pathogenic bioburden) are effective against a broad spectrum of microorganisms.⁹ Some topical antibiotics have been used with success, but these products should be kept to a minimum in light of the possibility of drug resistance increase. There are several resources available to the clinician for help with choosing the appropriate product. (See the “Suggested Reading” list at the end of the article for further information.)

Conclusion

       By using comprehensive assessment skills, the clinician in the extended care setting can determine the etiology of the wound and develop a plan of care accordingly. All disciplines involved in the care of the patient must be included to offer their expertise and facilitate wound healing. The patient and family must also be involved to determine mutual goals of treatment or therapy.
       The growing body of evidence regarding the biological processes within the phases of wound healing mandates that clinicians apply all the steps of wound bed preparation in the attempt to heal wounds. Systematically, clinicians can balance, minimize, or remove the barriers known to interfere with wound healing and decrease healing time. Cost effectiveness (ie, cost of the total care, not simply the cost of dressings), decreased infections, fewer dressing changes, decreased pain, and improved healing are some of the benefits of appropriate wound bed preparation. The dynamic nature of a wound requires continuous assessment of the patient as well as the wound to better prepare the wound bed for healing and ultimate closure.