Options for nonsurgical debridment of necrotic wounds

Advances in Skin & Wound Care,  Mar/Apr 2001  by Singhal, Anu,  Reis, Ernane D,  Kerstein, Morris D

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MARCH/APRIL 2001

EXTRA

CLINICAL MAGEMENT

DEBRIDEMENT

PURPOSE

To offer an educational experience that will help to improve the participant's understanding of the various types of nonsurgical debridement.

TARGET AUDIENCE

This CME/CE activity is intended for physicians and nurses with an interest in the prevention, diagnosis, and treatment of chronic wounds.

LEARNING OBJECTIVES

At the conclusion of this activity, participants should be able to:

1. Describe the role of debridement in wound healing.

2. Identify the different types of nonsurgical debridement.

3. Summarize the benefits and limitations of the different types of nonsurgical debridement.

4. Identify wounds that should not be debrided.

The authors thank Gae 0. Decker-Garrad for editorial assistance. Submitted November 16, 2000; accepted December 20, 2000.

ADV SKIN WOUND cARE 2001;14:96-103

Debridement is the removal of necrotic tissue, exudate, and metabolic waste from a wound. Accumulation of necrotic tissue results from a poor blood supply at the wound site or from increased interstitial pressure, a typical scenario in patients with pressure ulcers. Exudate usually results from infection. Staphylococcus aureus, for example, is known to produce a fibrin-rich biofilm that is resistant to the body's natural immune response to foreign bodies.1

The decision to debride a patient's wound represents an opportunity to improve the healing process. Despite scarce objective data, numerous agents and different types of interventions are used to remove debris from chronic wounds. Debridement may also be required to prepare the wound bed prior to application of some of the new biomaterials used to treat chronic wounds, such as cultured keratinocytes2 and a bioengineered human skin equivalent.3 As these modalities are used more extensively in clinical practice, selecting the appropriate debridement option will become more critical.

Several types of debridement are available, including mechanical, chemical, and autolytic.4 No standard protocol can be applied to all patients, however. Optimal wound management requires the selection of treatment options according to wound and patient characteristics and resources. This article will highlight the options available for nonsurgical wound debridement.

Role of Debridement

Debridement plays an essential role in the wound healing process. It reduces the bio-burden of the wound; controls and potentially prevents wound infection, especially in deteriorating wounds; and allows the practitioner to visualize the wound walls and base to assess viable tissue. If necrotic tissue is not removed, it not only can impede wound healing, but it can also result in protein loss (through large open wounds), osteomyelitis, generalized infection, septicemia, limb amputation, or even death.5

In an otherwise healthy person, the body's natural defenses will keep a wound debrided. Natural debridement, however, cannot keep pace with the accumulation of necrotic tissue in certain patients, such as those who are malnourished or have comorbidities, or in certain types of wounds, such as pressure ulcers. In those cases, the practitioner must intervene to prevent impaired wound healing.

Necrotic tissue (also called devitalized or dead tissue) has a characteristic moist, yellow, green, or gray appearance, although it may become thick, leathery black eschar if the wound dehydrates. Wound healing is impaired in the presence of necrotic tissue due to a lack of oxygen and nutrients. The accumulated dead tissue can also serve as a breeding ground for bacteria, and it may mask underlying buildup of fluid or abscesses.

Removing the necrotic tissue will restore circulation at the wound site. Adequate oxygen delivery to the wound is critical to healing. Wounds at sites of rich blood supply, such as the scalp, heal faster and are less prone to infection.67 Oxygen is required for energy-dependent metabolic processes, production of free radicals that kill bacteria, and proliferation of cells, such as fibroblasts and epithelial cells, which are crucial for wound healing.8-11 Bacterial overgrowth under hypoxic conditions may compete with the healing tissue for nutrients and produce exotoxins and endotoxins that could damage newly generated and mature cells.12

Contraction, initiated by migration of fibroblasts into the extracellular matrix, is a fundamental step in wound healing. Fibrils of collagen produced by fibroblasts are arranged as a mesh, laying the foundation for cells to grow and cover the wound.13 Although debridement is required for healing, it may destroy the framework necessary for healing if too much tissue is debrided.

When used appropriately, debridement encourages wound healing and avoids the potential problem of harming the wound. The following section discusses the various options for debridement.

Types of Debridement Mechanical debridement

Methods of mechanical debridement include the use of wet-to-dry dressings, whirlpool, and wound irrigation (pulsed lavage). Mechanical debridement, however, does not always discriminate between viable and nonviable tissue; newly formed epithelium can also be removed by these methods.14