How to formulate a treatment plan that works
Evaluation of any wound must begin with careful inspection, examination of the patient, and investigation into its etiology. Wounds—especially those resistant to healing with conventional measures—may be due to a number of causes, including mechanical trauma, chemical injury, vascular compromise, infection, neoplasm, pressure, and allergic reaction. Prior to forming a treatment plan, the cause of the wound and any contributing factors should be mitigated and/or eliminated.
The careful inspection of the wound must be accurate and done at regular intervals. The caregiver must evaluate the wound, the surrounding skin, and the overall health status of the patient.When evaluating a wound, specific points should be considered. Parameters that should be evaluated on a regular basis are location, size, and shape; presence of exudate, granulation or necrotic tissue; undermining or sinus tract formation; and involvement of neighboring structures (Figure 1).
Diagnostic tests may be helpful in formulating a comprehensive treatment plan. Commonly ordered tests include a complete blood count and wound culture and/or tissue biopsy to determine if there is concomitant infection or malignancy. The total protein, albumin, and prealbumin levels are used to evaluate the nutritional status of the patient. Doppler waveform analysis, segmental blood pressure, and transcutaneous oxygen monitoring help determine whether tissue oxygenation in the vicinity of the wound is adequate. Frequently ordered imaging studies include plain radiographs or nuclear bone scans to rule out bone involvement or osteomyelitis. Angiography, and sometimes venography, can be used in the correct clinical scenarios to document adequate circulation.
It must be stated that the best way to treat a wound is to prevent one. Wounds are dynamic and, once established, often require multiple treatment modalities and intensive efforts to heal. Both the wound and the patient require continual reassessment. The original treatment plan may change as a reflection of its effectiveness or noneffectiveness. Traditional wound care regimens have proven efficacy, while modern wound products often introduce greater expense but can save the caregiver time and increase patient comfort.
Traditional wound care is multi-faceted. Basic recommendations from the Agency for Health Care Policy and Research (AHCPR) include: inspecting the wound at least once a day, minimizing environmental factors that contribute to poor healing, avoidance of pressure over bony prominences, use of proper positioning and transferring techniques, use of lubricating agents to prevent shearing forces, maintenance of thermal insulation, institution of a rehabilitation program, and institution of a system for monitoring and documenting outcomes. Health care professionals have many decisions to make when it comes to healing a wound. These include which type of debridement modality, what kind of dressing to use, how to control infection, and which therapy will ultimately result in a healed wound.
The initial therapy usually involves debridement of the wound. Necrotic tissue should be excised, since it serves as a barrier to healing tissue. This is best done surgically, but it may not be tolerated in severely compromised patients. Determining how much tissue to excise involves careful inspection of the wound. Areas of undermining should be removed, and tunnels should be opened (Figure 2). The edges of the debrided wound should demonstrate adequate vascularity, as evidenced by bleeding from the dermal and subdermal vessels.
After debridement and inspection of the wound, decisions should be made as to whether or not antibiotic therapy is required. An important component to therapy is the identification and elimination of infection, both locally and systemically. Diagnosis of local wound infection may be based on purulent exudate or may require wound biopsy and quantitative culture. Local wound infection can be controlled with a multitude of available antibiotic-containing creams or ointments. In addition, antimicrobial solutions can be substituted for saline in the wet-to-dry dressings that are bacteriocidal. In cases where the wound is causing systemic sepsis, oral or parenteral antibiotic therapy should be initiated. The antibiotic chosen must address the flora commonly found in the skin and subcutaneous tissues. These include species of Staphylococcus and Streptococcus. Appropriate first-line agents are the penicillins and first- and second-generation cephalosporins. A change in the antibiotic regimen should be dictated by initial or follow-up wound or blood culture results.
The most commonly used traditional dressing is wet-to-dry gauze. The gauze should be sterile and moistened with sterile saline. After wringing out excess saline, the damp gauze is packed into the wound and covered with dry gauze. The surrounding skin should be dry to prevent maceration of the wound edges. At the next dressing change, the gauze should be partially dry so that removal serves to debride fibrinous exudate from the margins of the wound that would otherwise impede healing. Such dressing changes may be uncomfortable, and patients often request moistening the dressing prior to removal. Moistening the old gauze, however, defeats the purpose and function of the dressing and should be discouraged.
Newer wound dressings include films, hydrocolloids, alginates, foams, gels, exudate absorbers, vacuum sponges, and biologic dressings. All have specific advantages and disadvantages that must be weighed against the nature of the wound and the wound care setting.
Film dressings have the obvious advantage of being transparent so that the wound can be continually inspected through the dressing. Films are advantageous by being waterproof and creating a moist, warm environment for healing. They are also economical, as compared to more advanced wound care products. The major disadvantage is that they are unable to absorb excess fluid or odor and thus are prone to leakage with fluid buildup. Transparent dressings serve as excellent donor site dressings for skin graft harvest sites if the sites are not too large and do not border hair-bearing areas, which causes them to lose their adherence to the site.
Like the films, hydrocolloids are waterproof, adhesive and comfortable. They have the added benefit of being able to absorb excess wound fluid. However, the hydrocolloids can become malodorous between dressing changes and need to be changed more frequently than traditional dressings.
Gel and alginate dressings are similar in their cost/benefit profile. Both are able to hydrate dry wounds and debride necrotic wounds. They are comfortable for the patient, easy to apply for the caregiver, and applicable to all phases of wound healing. They do, however, require a secondary dressing for coverage to keep the gel or alginate material in contact with the wound and thus add to the expense of treatment.
Topical foam dressings are able to absorb exudate produced within a wound without being uncomfortable or malodorous. Unlike some other products, foams tend not to leave a residue that requires removal before reapplication. The foam itself, however, may run out before the subsequent dressing change.
Natural enzymes have been formulated into topical ointments for wounds. These enzymatic formulas offer an alternative to surgical or mechanical debridement. They are especially useful in patients who would not be able to tolerate surgical debridement. Two enzymatic agents are currently available in the Unites States. One is papain-urea, which is formulated in a cream base. The other is collagenase, which exists in a petrolatum base. Papain-urea is useful for digesting tissues composed of fibrin, while collagenase is more effective in removing tissues composed of elastin. Both enzymes work to digest eschar and necrotic tissue in the wound. One disadvantage of enzymatic therapy is cost of the product. However, if time to debridement and wound closure is lessened, the overall cost may be lessened over conventional treatment with dressing changes. Another concern is that the enzyme formulations may digest vital growth factors, which are secreted into the wound and are important in healing.
Another agent for debridement is the maggot. While not commonly used today, the technique is regaining popularity. In January of 2004, the FDA approved the use of maggot, or fly larva, as a medical device. In the 16th century, Ambroise Pare took note of the maggots’ ability to clean a suppurative wound. Work in the 1930s by William Baer produced sterile maggots, eliminating the introduction of bacteria from the GI tract of the maggot. However, their use declined in the mid-portion of this century with the advent of antibiotics. Maggots are noted to debride necrotic tissue, leaving only the viable tissue in a wound untouched. Their presence also appears to stimulate granulation and angiogenesis in wounds. They have been used in a variety of clinical situations from pressure ulcers, burns, diabetic ulcers, and venous stasis ulcers. Some studies suggest that preoperative wound preparation with maggots decreases the rate of postoperative wound infection after surgical closure of wounds.
The vacuum sponge also deserves mention as a dressing since it is becoming more prevalent used as an in-hospital dressing and slowly becoming a dressing for patients at home. The system uses a medical-grade sponge that may be custom tailored to fit the specific size and shape of a wound. It is connected to a drainage tube and covered with an adhesive, waterproof film dressing. (Figure 3). The tube is connected to constant suction and serves to eliminate exudate from the wound, maintain a moist environment, and minimize contamination. It may be left in place for several days and changed with minimal difficulty at the bedside. It has been shown to be valuable for both open wounds and as a stable dressing over skin grafts to prevent fluid accumulation and shear beneath the graft. There are a multitude of articles citing the various scenarios in which vacuum therapy may be used.
Biologic dressings include xenografts and tissue-cultured grafts. Xenografts commonly come from pigskin and are used in wounds with a questionable bed where risking limited autogenous skin would be unwise. The xenografts are placed onto the wound and dresses in the same manner as an autogenous graft. Adequate “take” of the xenograft is indicative of a healthy wound bed. Cells cultured from neonatal foreskin have also been developed and used for treatment of difficult wounds where donor site morbidity might be a problem.
Another relatively new avenue of research in wound care is the use of growth factors—normally present in healing wounds. Currently, becaplermin is the only FDA-approved growth factor. It is recombinant platelet-derived growth factor (PDGF), which has been shown to speed healing of neuropathic wounds. Off-label uses of PDGF are at the discretion of the physician. Research is continuing into its applicability for pressure wounds. To date, there has been conflicting evidence as to whether it is beneficial over conventional treatments. Current research in the field of gene therapy is investigating the use of viral vectors to deliver growth factors into the cells surrounding non-healing wounds.
The ultimate choice of wound therapy depends on many factors. The frequency of the dressing change must be weighed against its ease or difficulty. Likewise, the availability of a given dressing or medication must be weighed against the ultimate cost, not only to the patient, but also to the health care system. n
Peter J. Taub, MD, FACS, FAAP, (pictured at right) is assistant professor, surgery and pediatrics at New York Medical College and Westchester Medical Center. He can be reached at (914) 493-8661 or by email at [email protected]
Marco A. Harmaty, MD, Division of Plastic and Reconstructive Surgery, Mount Sinai Medical Center, New York, NY. He can be reached at (212) 241-5873 or by email at [email protected]
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