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Nonsurgical methods of debridement
Nonsurgical methods of debridement
Autolytic Autolytic debridement is the most natural and selective form of debridement. During the inflammatory phase of wound healing, serine proteases and MMPs are released by neutrophils to degrade devitalized and foreign material.36 Autolytic debridement takes advantage of this natural process, and is performed through the use of occlusive moisture-retentive dressings that provide an optimal wound environment for endogenous proteolytic enzymes to degrade devitalized material.6,7
Occlusive dressings increase the rate of wound healing; in a porcine model, partialthickness wounds covered with a polyethylene film were found to heal twice as quickly as uncovered wounds.37 These results were later corroborated in a similar study involving partial-thickness wounds in healthy human subjects.38 In a prospective study by Nemeth et al., patients who received either shave or 3-mm punch biopsies were treated with either an occlusive hydrocolloid dressing or by conventional wound therapy. Occluded wounds were more likely to heal than controls, and the treatment group was less likely to experience pain in comparison to the control.39 In another prospective study involving chronic wounds, a hydrocolloid/alginate spiral dressing and hydrocolloid secondary dressing was used in the management of stage III and IV pressure ulcers. Both ulcers which were surgically debrided prior to the study and those that were not had decreased amounts of fibrin slough and necrotic tissue on study completion.40 In another randomized controlled trial, autolytic debridement of chronic leg ulcers had similar efficacy to a commercially available enzymatic debriding agent, determined by reduced amount of eschar and fibrous slough and increased granulation tissue and reepithelialization.41
The major categories of occlusive dressings used for autolytic debridement include polymer films, polymer foams, hydrogels, hydrocolloids, and alginates. Individual wound characteristics dictate the choice of a particular dressing to ensure maintenance of moisture balance. Polymer films, hydrogels, and hydrocolloids maintain a moist environment, while foams and alginates have absorbent properties.42 However, combinations of these products may be utilized to promote a moist environment while protecting the surrounding tissue from excess moisture.7 Autolytic debridement should not be used in patients with infected wounds or deep wound cavities. Dressings are typically left on for 2 to 3 days and should be irrigated with normal saline upon removal to discard the liquefied necrotic debris.
Autolytic debridement confers the advantage of being generally pain-free. However, it is slower than other forms of debridement, and multiple rounds of dressing
application and irrigation may be required to elicit the desired effect.6 Autolytic debridement also does not debride cells deep in the wound bed or wound edge. Another drawback is the possibility of maceration of surrounding healthy skin.7 On each dressing change, wound fluid should be examined for signs of infection, including purulence and odor, and the patient should be assessed for inflammation and increased wound pain. If infection is suspected, autolytic debridement should be discontinued and a more rapid form of debridement, such as surgical debridement, should be employed to avoid aggravating the infection and adversely affecting the healing process.6
Enzymatic (Chemical) Enzymatic or chemical debridement involves the topical application of exogenous enzymes onto the wound bed to dissolve slough and devitalized tissue. Collagenase is a selective enzyme derived from the bacterium Clostridium histolyticum. It is more effective at degrading collagen and elastin43 and has been shown to increase endothelial and keratinocyte migration.44
Enzymatic debridement has the advantage of ease of use compared to other forms of debridement. Collagenase typically requires once-a-day application.6,7 Collagenase is also relatively safe, though there have been reports of transient erythema if collagenase application is not confined to the wound bed.6,43 Products containing heavy metals, such as silver sulfadiazine, should not be used in conjunction with collagenase, as they have an inactivating effect.6
Mechanical Mechanical debridement is the use of force to remove loose, devitalized tissue. It is a nonselective form of debridement, as it could potentially harm viable tissue, and may be associated with pain.23 Wet-to-dry dressings changes are the most common technique, and are useful in the removal of fibrin from wounds. This method involves the application of a saline-moistened gauze onto a wound, letting it dry, and removing the dry gauze from the wound. It is usually repeated once or twice daily; it is discontinued and switched to an advanced wound dressing once a clean, granulating base is reached.7,8 However, wet-to-dry dressing removal can be very painful, requiring premedication, and may cause bleeding and damage to viable, newly formed skin.8 Mechanical debridement does not debride cells at the wound edge.
Mechanical debridement may also be accomplished by other means, including forceful irrigation via pulsed lavage, whirlpool therapy, or ultrasonography.6,23 Pulsed lavage involves flushing a wound with saline at no more than 15 psi of pressure using a syringe to drive out necrotic debris. Whirlpool therapy is offered at certain facilities, using fast-moving water to remove loose debris, though this method poses concerns with risks of contamination and infection.6-8 A novel form of mechanical debridement
involves the use of low-frequency ultrasound for the mechanical debridement of wounds, though trials demonstrating its efficacy are pending.45
Biologic The use of maggots for debridement is an early practice that has reemerged as a method to rapidly debride chronic wounds. Sterilized, medical-grade Lucilia sericata, Phaenicia sericata, and Lucilia cuprina maggots are usually reserved for debridement of intractable wounds with abundant fibrinous material.23 The larvae secrete enzymes in their saliva that work to liquefy necrotic tissue.46 Maggot therapy should not be used in patients with life- or limb-threatening infections, issues with hemostasis, or deep tracking wounds.47 Barriers to use include patient and provider psychological distress as well as pain, which was demonstrated in a recent randomized controlled trial.23,48 Biologic debridement using maggot therapy has been shown to reduce time to debridement, though it has not proven to positively impact healing.49,50