A chronic wound, often defined as any wound that remains open after 30 days, places patients at higher risk for local and systemic complications. Chronic wounds are associated with increased costs to the healthcare system and decreased quality of life. Chronic wounds can be related to a number of etiologies, including venous hypertension, arterial insufficiency, pressure ulcers and trauma. A process known as wound bed preparation can improve outcomes and reduce costs when employed consistently and rapidly after lesion formation.1
Wound Bed Preparation and Debridement
First proposed by Falanga,2 the concept of wound bed preparation requires removal of cellular debris and devitalized tissue (debridement), treatment of infection, management of exudate and enhancement of wound edges. Table 1 lists interventions associated with each of these goals. Initially conceived as a step-by-step process using evidenced-based interventions, more recent literature suggests that debridement can accomplish all of these objectives.3,4
Wound debridement can be accomplished through a variety of mechanisms. Urgent surgical debridement in the operating room is indicated for wounds with advancing cellulitis unresponsive to intravenous antibiotics; necrotizing fasciitis or soft tissue infection with or without an abscess; and extensive devitalized tissue associated with trauma or burns. These are outside the scope of this article. This article reviews debridement options for nonoperative candidates in outpatient, subacute care, long-term care and acute care settings.
Clinical decision making to determine the best method for wound debridement requires a comprehensive framework consisting of three elements: examination of patient factors, clinician skill and environmental influences.
First and foremost, the provider must decide whether the patient requires surgical intervention. Is debridement required at all? The presence of devitalized or nonviable tissue requires active intervention. This first step, known as initial debridement, is contraindicated in stable, dry black eschar in areas with known vascular compromise. The area that most frequently meets this criteria is the intact black ulcer seen on the calcaneus. Initial debridement can be performed using techniques listed in Table 2.
Don't be fooled into thinking that a clean pink or red wound does need debridement. Wounds with this type of appearance require maintenance debridement.The host will attempt to undergo autologous debridement of nonviable material. Through chronicity, the wound no longer goes through an orderly process of cellular debris removal through apoptosis.5 Instead, increasing and persistent inflammatory cytokines allow cellular debris to accumulate. Colonization of bacteria that form biofilm fuels this vicious cycle. It is often what isn't seen in the wound that requires intervention. Maintenance debridement2 should be employed routinely using the methods listed in Table 2.
Determining scope-of-practice regulations for wound debridement in the state where you practice is the first step in selecting debridement options. For example, a PA who is under direct supervision of a physician may be permitted to perform bedside sharp debridement but the NP colleague in the same state may be prohibited from this same practice due to state nurse practice act restrictions.
Figure 1: The initial presentation of the patient in the case example. Photos courtesy the author
Figure 2: The wound 7 days after debridement began.
Figure 3: At this point, the wound had epithelialized and wound care was discontinued.
Self-knowledge and competence in a particular treatment method should be assessed, as should the availability of the equipment or other materials needed to initiate initial or maintenance debridement. In many cases, debridement can be accomplished in a variety of ways. Thought should be given to patient and family preference, once they have been educated in available options.
Don't discount the skill level of other providers who may also be carrying out the debridement plan over a period of time. For example, while biodebridement using sterile maggots can be a safe, effective and rapid way to perform initial debridement, many patients refuse this option. Furthermore, it may be difficult to find a homecare provider who is skilled in certain types of localized wound care. Physical therapists often have the necessary training and equipment to provide advanced debridement modalities, so it is beneficial to seek out these providers for collaboration.
The clinical setting in which initial or maintenance debridement occurs is crucial. Patients can come to the office for weekly wound debridement using a curette, but they must receive ongoing therapy using a local dressing or application of an enzyme to the wound between visits to continue initial debridement or provide maintenance debridement. Providers in acute or long-term acute care hospital settings often have access to high-tech equipment for debridement, such as noncontact, low-frequency ultrasound or pulsed lavage. Conversely, some long-term facilities and home health agencies have strict formularies the clinician must adhere to, limiting the ability to achieve initial or maintenance debridement goals in a timely fashion.
Debridement can be accomplished through five general strategies: mechanical, sharp, biosurgical, autolytic and enzymatic debridement. Selective debridement is often preferred to a nonselective modality, since the process spares healthy tissue. It is common for subspecialty clinicians not well-versed in wound care to select one method throughout the healing process. But the use of synergistic strategies and changing methods as assessment dictates is key to wound re-epithelialization.
Mechanical Debridement. Ultrasound, pulsed lavage and other physical modalities are underutilized, primarily due to their specialized nature outside certain settings. Whirlpool therapy, though still used, is falling out of favor due to the potential for bacterial contamination and transmission. Additionally, the intense labor utilization necessary to perform whirlpool therapy does not make it cost-effective.
Clinicians continue to use wet-to-dry dressings despite the evidence that a moist wound bed achieves superior outcomes. Additionally, this method has slower healing rates, is associated with aerosolization of bacteria, and is painful to the patient.6
The time frame required to achieve complete initial debridement may vary from several days to weeks, depending on the method used and the wound etiology. Wounds associated with vascular issues tend to take longer to heal. Intermittent use of these methods can promote maintenance debridement as long as there is sufficient vascular supply on both micro- and macrovascular levels.
Sharp Debridement. This modality refers to the use of a scalpel or curette at the bedside or in the office setting. It removes only devitalized tissue or accumulated debris on the wound bed. The use of a topical anesthetic agent prior to initiating sharp debridement may reduce discomfort. It is important that the clinician performing this procedure has the ability to provide hemostasis should an unexpected event occur.
Sharp debridement rapidly removes bulk devitalized tissue, reducing residual nonvisible debris but not eliminating it. This method should be used in conjunction with a modality that addresses maintenance debridement. Since sharp debridement is a nonselective form of debridement, granulation tissue that is well established will be harmed during this process.
Performing curettage on the edges of the wound can stimulate wound healing. Although optimal intervals have not been established, frequency should be weekly or biweekly. Saucerization refers to the removal of thick, sometimes macerated callus that encircles the wound. Saucerization is common in patients with diabetic foot ulcers, and cutterage is essential to restoring normal keratinocyte migration.
Biosurgical Debridement. Sterile maggots applied to a wound can actively and selectively reduce visible devitalized tissue. In addition to the "yuck" factor many patients have when approached about initiating this modality, patients sometimes report feeling the presence of the larvae. Despite this, the literature reports rapid and painless debridement of necrotic tissue with this strategy.1 A count of the number of larvae applied and removed must be performed at each dressing change. Additionally, a nonocclusive secondary dressing that provides larval containment is required.
Autolytic Support. Once considered the preferred method for debridement, autolytic support relies on topical wound dressings that allow the patient's own enzymes to debride the visible necrotic tissue. Autolytic support is dependent on an immunocompetent host. Patients with advanced age, cancer, diabetes or other disease states associated with immunosuppression do not have fully functioning endogenous enzymes that are up to this task.
Autolytic support acts passively and has the most prolonged debridement times, so its status is more as a "support" role in exudate management rather than a debridement option. Autolytic support has no role in maintenance debridement but it is an excellent choice in chronic wound patients whose plan of care is not aimed at wound healing, such as patients receiving end-of-life care. Hydrocolloids, medical-grade honey, alginates and hydrogels are examples of these types of dressings.
Enzymatic Debridement. A number of enzymes have been used on chronic wounds in the last 50 years. However, only collagenase remains in use today. Its action selectively cleaves the denatured collagen bonds that hold necrotic tissue in the wound. Additionally, collagenase promotes fibroblast proliferation and keratinocyte migration.7 Collagenase must be applied daily in a 2-mm thickness to be effective. Compatible with a number of antimicrobial dressings and agents,8 the activity of the enzyme, and therefore its outcomes, are moisture dependent. This means careful thought must be exercised to determine the most suitable cover dressing. The literature reports that debridement ranges from 5 to 42 days using this approach.9 When used in a long-term care setting, enzymatic debridement was superior to hydrogel in terms of weekly reduction in nonviable tissue and reduction in wound size.10 It is suitable for both initial and maintenance debridement.
John is a 67-year-old man with type 2 diabetes and hypertension. He comes to the office after sustaining a burn on his leg. He treated it with an over-the-counter triple antibiotic ointment for 1 week, but the blister area turned black and he is seeking help. No systemic clinical signs of infection are present (Figure 1). Debridement decision: The wound meets criteria for debridement.
Goal: Initial debridement. Clinician skill: Not comfortable using a scalpel. Patient factors: Able to change and apply own dressings, has prescription coverage; diabetes will affect therapy choice. Environmental influences: Will not need home health skilled nursing, lives with spouse, no animals in home. Debridement choice: Daily enzymatic debridement with nonadherent adhesive dressing readily available at local pharmacy.
John returns to the office 7 days later for a re-evaluation of the wound (Figure 2). Goal: Maintenance debridement. Clinician skill: Many options now available. No curette available in office setting. Patient factors: Blood sugar well controlled, able to obtain needed pharmaceutical and cover dressings. Environmental Influences: Reports no problems in accomplishing wound care. Debridement choice: Continue current wound care.
Three weeks after the initial presentation to the office, John returns for follow-up. The wound has now epithelialized and wound care is discontinued (Figure 3).
When choosing a debridement method, it is important to objectively evaluate the outcomes of clinical decision making. Using a reliable and valid wound assessment tool can assist you in this method. Choices include the Barber Measuring Tool, the Bates-Jensen Wound Status Tool, the Leg Ulcer Measurement Tool, the Pressure Sore Status Tool, the Pressure Ulcer Scale for Healing, the Sessing Scale, the Sussman Wound Healing Tool, and the Wound Bed Score.
No current tool singularly measures debridement effectiveness prospectively, but all have a subset numerical scale that evaluates this component of wound bed preparation.
Initial and maintenance debridement of the chronic wound is an essential component of wound management. Clinicians in all settings have access to at least one process to achieve the clinical goals of a clean, healthy wound bed.
Catherine T. Milne owns Connecticut Clinical Nursing Associates in Bristol, Conn., a practice focused on wound care. Milne is certified in adult health and chronic wound care. She is a member of the board of directors of the National Association of Dermatology Nurse Practitioners (www.nadnp.net).
1. Albaugh KW, Loehne HB. Wound bed preparation/debridement. In: Kloth L, McCulloch J, eds. Wound Healing: Evidence Based Management. 4th ed. Philadelphia, PA: F.A.Davis; 2010: 155-179.
2. Falanga V. The chronic wound: impaired healing and solutions in the context of wound bed preparation. Blood Cells Mol Dis. 2004;32(1):88-94.
3. Falanga V, et al. Maintenance debridement in the treatment of difficult-to-heal chronic wounds. Recommendations of an expert panel. Ostomy Wound Manage. 2008;54;6(Suppl 1):S2-S13.
4. Milne CT, et al. A comparison of collagenase to hydrogel dressings in maintenance debridement and wound closure. WOUNDS. 2012;24(11):317-322.
5. Sussman C, Bates-Jensen B. Wound healing physiology: acute and chronic. In: Wound Care: A Collaborative Practice Manual for Health Professionals. 4th ed. Philadelphia, PA: Lippincott, Williams and Wilkins; 2011: 42.
6. Cowan LJ, Steckmiller J. Prevalence of wet-to-dry dressings in wound care. Adv Wound Skin Care. 2009;22(12):567-573.
7. Shi L, et al. Degradation of human collagen isoforms by clostridium collagenase and the effects of degradation products on cell migration. Int Wound J. 2010;7(2):87-95.
8. Jovanovic A, et al. The influence of metal salts, surfactants, and wound care products on enzymatic activity of collagenase, the wound debriding enzyme. WOUNDS. 2012;24(9):242-253.
9. Ramundo J, Gray M. Collagenase for enzymatic debridement: a systematic review. J Wound Ostomy Continenc Nurs. 2009;36(6S)(Suppl-1):S4-S11.
10. Milne CT, et al. A comparison of collagenase to hydrogel dressings in wound debridement. WOUNDS. 2010;22(11):270-274.