Non-surgical Debridement of Burn Injuries

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Original Editor - Stacy Schiurring based on the course by Diane Merwarth

Top Contributors - Stacy Schiurring, Jess Bell and Matt Huey

Introduction

Please see this article for a list of useful wound care terminology.

Indications for Debridement

Indications for debridement:

• Remove devitalised tissue, this is the primary function of debridement. The presence of non-living tissue in a wound bed impedes wound healing by:
  • acting as a nutrient source and ideal living environment for unwanted microbes which can cause infection
  • creating a physical barrier for re-epithelialisation
  • creating a barrier against topical antimicrobial agents which limits their ability to manage infection in the wound
• Stimulate the wound bed in chronic wounds to reinvigorate the wound healing cascade. The presence of non-living tissue in a wound bed effects the wound healing cascade by inhibiting:
  • angiogenesis (the formation of new blood vessels from existing vasculature)
  • granulation tissue formation
  • re-epithelialisation

Surgical excision of non-viable tissue is the standard of care, however there are times when less aggressive debridement methods are required. This can include:

1. Medically unstable patients who could not tolerated sedation and/or surgical interventions
2. Surgical resources not available
3. Non-surgical management is preferred
4. Areas of deep partial and full thickness injury are small and can be properly managed with less invasive methods
5. Area of the burn wound injuries is not serious enough to warrant surgery
6. The risk of surgery damaging vital structures is greater than non-surgical care such as on the fingers or hands

Images for this section: eschar, necrotic tissue, slough, bioburden, biofilm, and those apoptotic or senescent cells that accumulate on the surface of the burn.

Non-surgical Debridement

Non-surgical debridement is the removal of materials which limit or impair healing from a wound bed without by means other than sharp excisional methods into viable tissue in a sterile surgical setting. Examples of unwanted materials in a wound can include: eschar, necrosic tissue, bioburden, biofilm, or foreign matter.

This article will explore five types of non-surgical debridement: (1) mechanical, (2) autolytic, (3) local sharp, (4) biosurgical, and (5) enzymatic.

Mechanical Debridement

"Mechanical debridement is a nonselective type of debridement, meaning that it will remove both devitalized tissue and debris and viable tissue. It is usually carried out using mechanical force."

The amount of force applied during mechanical debridement is subjective and is based on the wound care professional's clinical skill and comfort level. Currently, there is little evidence in the literature to support the use of mechanical debridement in the treatment of burn wound injuries.

Indications for mechanical debridement:

• acute and chronic wounds with moderate to large amounts of non-viable tissue
• can be used regardless of the presence of active infection

Contraindications for mechanical debridement:

• greater percentage of granulation tissue than devitalised tissue in wound bed
• inability to control pain
• patients with poor perfusion
• intact eschar with no clinical evidence of an underlying infection.

Clinical Pearls: a deeper look at eschar

explain stable versus unstable eschar

Examples of mechanical debridement:

1. Pulsatile lavage. Involves moderate-to-high pressure irrigation which is well controlled and known to be safe for the surface of wounds, including burn wounds.
2. Wound Irrigation. Can be achieved using a syringe with a known gauge needle to provide a known amount of pressure. Not commonly effective for use in burn wound injuries.
3. Shower. Please see this article for more information.
4. Whirlpool. Please see this article for more information, especially regarding the physiological responces and risks of whirlpool use with burn injuries.
5. Scraping. Achieved using the edge of a scalpel, a curette, or some other flat instrument, such as a tongue blade, to scrape the surface of the burn wound and remove any loosened debris.
6. Wet-to-dry dressings. Involves applying gauze which has been moistened with either saline or an antimicrobial agent on to the surface of the burn wound, allowing the gauze to dry, then removing it from the bur wound surface. As the gauze dries, anything on the wound surface, which can be loosened devitalised tissue or healthy granulation tissue, can adhere to the gauze. When the gauze is removed, both types of tissue is ripped off the wound surface. This method of debridement can be very painful and highly nonselective.
7. Soak and wipe. Involves applying towels or gauze saturated with saline or an antimicrobial solution to the surface of the burn wound and allow them to "soak" for 5-10 minutes. Next, using a saturated gauze, wipe the wound surface with an applied force in circular motions to remove debris. The wiping is performed to the patient's tolerance. Caution should be taken to only use clean gauze when wiping, and discard gauze as it collects devitalised tissue. When treating a large burn wound, only expose a small area at a time to prevent hypothermia. Please see this article for more information.

Special Topic: Wet-to-Dry Dressings

Once well known and widely used, now no longer considered standard of care. Evidence based practice ...

Advantages

• Quick to perform with appropriate pain management
• Can be used with active infection
• Efficient for larger wounds
• Effective at bedside or in the outpatient setting with adequate pain management. And there was one study that showed the effectiveness of pulse lavage. This was a study that was done after surgical excision of the burn wound, then using pulse lavage to clean the surface of the burn wound, and then a skin graft is applied to that cleaned wound bed. And this study showed that using pulsatile lavage after surgical excision increased the success rate of skin graft take and decreased the amount of infection that occurred after that skin graft surgery.

Disadvantages

• Very non-selective form of debridement
• Very painful

Autolytic Debridement

"[Autolytic] debridement is a natural process by which endogenous phagocytic cells and proteolytic enzymes break down necrotic tissue. It is a  highly selective process whereby only necrotic tissue will be affected in the debridement."

This is the most conservative type of debridement. Autolytic debridement involves dissolving or separating eschar from the underlying dermis to allow it to be removed or debrided away. A moist dressing environment optimises autolytic debridement. The effectiveness of autolytic debridement depends upon the amount of devitalised tissue present in the wound and the true wound size.

Indications

• recommended for non-infected wounds, however can be used with other debridement techniques, such as mechanical debridement, in the case of infected wounds.

Contraindications

• Immuno-compromised patients

Examples of dressings that facilitate autolytic debridement:

1. Hydrocolloids (most effective)
2. Hydrogels
3. Transparent films
4. Medical grade honey

Advantages

• Very selective because it only targets the necrotic tissue
• Essentially painless
• Fairly simple process to utilise

Disadvantages

• Slow debridement process when compared to other methods
• Not indicated in the presence of an active infection
• Not effective or efficient for use in burn wound with large surface areas

Local Sharp Debridement

"Devitalized tissue (slough, necrotic, or eschar) in the presence of underlying infection is removed using sharp instruments."

Tools that can be used for local sharp debridement include: scalpel, scissors, and/or curettes.

Indications

• Recommended for infected wounds
• Can be combined with all the other debridement methods

Contraindications

• Patients on anticoagulation therapy due to bleeding risk
• Intact eschar and no clinical evidence of an underlying infection

Advantages

• Can be fairly quick
• Very specific form of debridement
• Good method for bedside or outpatient procedures

Disadvantages

• Can be painful
• Can be an invasive procedure, depending on the depth of debridement
• Skill requires specialized training, certification, and/or licensure. Please review your local practice act and complete appropriate and required training before performing as part of a wound care treatment plan.

Biological Debridement

Biological debridement (larval therapy, maggot therapy, biosurgery) uses sterile larvae of the green bottle fly to debride devitilised tissue. This is done via the release of proteolytic enzymes from larvae secretions and excretions which dissolve necrotic tissue from the wound bed.

The larvae are applied directly to the wound bed and can be either enclosed and contained in a "biological bag" or "free range." Research has shown that biological debridement performed by free range larvae is twice as fast has those enclosed in the biological bag.

Other benefits of biological debridement include:

1. Bacteriocidal, as the larvae ingest and digest bacteria
2. Inhibiting bacterial growth by producing in releasing ammonia into the wound bed, which increases the wound pH
3. Breakdown of existing biofilm at the wound bed and inhibition of new biofilm growth
4. Direct ingestion of necrotic tissue

Advantages

• Essentially painless
• Very selective form of debridement
• Fairly rapid and can debride areas that are difficult to access by other debridement methods
• Appropriate for use on large wound areas

Disadvantages

• Containment of the larvae, limits application in the outpatient setting
• Patient or caregiver acceptance of the treatment intervention

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Enzymatic Debridement

This is a selective method for debridement of necrotic tissue using an exogenous proteolytic enzyme, collagenase, to debride Clostridium bacteria. Collagenase digests the collagen in the necrotic tissue allowing it to detach.

enzymes are chemical agents that are composed of exogenous proteolytic enzymes to debride the necrotic tissue in a burn wound or any wound in general. Enzymes have probably been the most extensively studied of the forms of mechanical debridement that I've talked about today. And currently there are only two enzymes available on the market.

Collagenase and moisture retentive dressings can work in synergy, enhancing the debridement.

Indication

Contraindications

A relative contraindication of enzymatic debridement is its use in heavily infected wounds. Furthermore, collagenase should not be used in conjunction with silver-based products or with Dakin solution.

NexoBrid It has also not been studied on chemical burns, so there's no known effect for that. They have found poor results in using the bromelain-based enzyme on early application for scald burns and in applying it to burn wounds on the surface of diabetic feet. And that needs further study because they're not really sure why those results are so poor. It's also not recommended for high-voltage electrical injuries or the established compartment syndromes, as I'd said before.

	Enzyme	Basic Application Procedure	Special Considerations
Collagenase	derived from the fermentation by Clostridium histolyticum possesses the unique ability to digest collagen in necrotic tissue	According to the Santyl website: Prior to Collagenase application the wound should be cleansed of debris and digested material by gently rubbing with a gause pad saturated with normal saline solution, then rinsed with normal saline solution If infection is present, an appropriate antibiotic powered should be applied to the wound prior to the application Collagenase. However, if the infection is not responding, enzymatic debridement treatments should be discontinued until the infection clears Collagenase may be applied directly to the wound or to a sterile gause pad which is then applied to the wound and properly secured. A vaseline-coasted gauze such as Xeroform or Vaseline gauze can also be used in multiple layers to maintain needed moisture in the dressing. Use of Collagenase Santyl Ointment should be terminated when debridement of necrotic tissue is complete and granulation tissue is well established. After the enzyme is applied, you cover it with a moist, non-adherent dressing. As I said before, you shouldn't use a silver-based dressing or anything with Dakin's on the dressing. Probably one of the easiest dressings to use over the collagenase is a Vaseline-coated gauze, such as Xeroform or Vaseline gauze, used in multiple layers to provide the moisture that the enzyme needs. It's also important to know that if there is not enough drainage or moisture from the wound itself to keep the enzyme activated, that the dressing put over the top of the enzyme needs to add moisture to the wound to provide that moist environment. The dressing, as I said, is changed daily at each dressing change. Other methods of mechanical debridement can be performed, just the soak and wipe or scraping, if there's loosened necrotic tissue to be removed, and then the process is repeated. Most studies and anecdotal reports that I've seen say that they discontinue the use of collagenase once the eschar has been eradicated. However, the manufacturer itself says that it is safe and effective in use throughout the wound healing process. And part of that is because of the effectiveness that it has on reducing fibrin and promoting that endothelial activity that was mentioned in the one study.	requires daily dressing changes not recommended to leave it on for more than 24 hours at a time when clinically appropriate crosshatch thick eschar with a #10 scalpel blade to increase the surface area contact of the ointment with necrotic debris
NexoBrid	bromelain-based enzyme derived from the stems of pineapples, and it provides multiple proteolytic enzymes in its formulation	As for the procedure for applying the NexoBrid to eschar in a burn wound, most of what I'm going to list has come from various studies, the consensus recommendations, and case reports. The insert that's included with NexoBrid from the manufacturer has very little detail as far as the application instructions. The main thing it does say is that the patient needs to be an inpatient when using NexoBrid for burn wound debridement, and it should be either in a burn unit or a burn centre, if at all possible. So the procedure is a combination of the insert as well as the insert of the manufacturer's recommendations as well as the consensus and some of the studies that I found. The current recommendations are that it should be only applied to an area of 15% total body surface area or less per application. It should be applied by a skilled practitioner such as an MD (medical doctor) or a nurse practitioner or a physician's assistant, usually in the operating room. The patient needs to have adequate pain medication during the application process and for the entire four hours that the enzyme is in contact with their burn wound. It's important to protect the peri-wound skin with a thick layer of petroleum or some other skin protectant to prevent maceration and to prevent burning of the NexoBrid on the skin, although it doesn't destroy or damage the skin, it can cause some burning and maceration. It should be applied in a thick layer and then covered with an occlusive dressing. It should not be used in combination with Silvadine or Betadine. And it should stay in place for four hours. At four hours the dressing is removed. There are some studies that showed performing mechanical cleaning or wet-to-dry dressings for a short period after removal of the NexoBrid dressing will help remove the residual non-viable tissue and the residual product that stays on the wound after that dressing has been removed. Then the wound bed needs to be assessed. If there is punctate bleeding, just little spots of bleeding throughout that burn eschar, then the burn is expected to re-epithelialise without the need of a skin graft. If there is more large-calibre vessel bleeding when that dressing is removed, then there is indication that a skin graft is needed to help complete the wound healing process. If a skin graft is not determined to be necessary at that particular time, then dressings are used to provide the moist wound environment for healing to continue. That can be allografts, if the resources are available, or some other form of skin substitute or dressings that your facility uses for ongoing burn care, preferably ones that can be left in place for several days at a time, so you're not disturbing that burn wound and the healing process can continue. If a skin graft is indicated, some studies or the consensus panel recommend a delay of two days to allow that burn wound to stabilise for the vascular granulation tissue surface to become more stable, so it will be ready to accept the skin graft. The bromelain-based enzyme has also undergone extensive studies. A compilation of the study results have found that after pre-soaking and applying the enzyme for four hours, followed by mechanical debridement and soaking overnight, a skin graft has an 86% rate of effectiveness once that wound, that skin graft has been applied after that overnight soaking. It also found that burns treated with the bromelain-based product usually only require one four-hour application to be successful in removing all of the eschar. It has contributed to fewer surgeries and smaller skin graft areas, which results in decreased blood loss and decreased time to complete eschar removal on the surface of that burn wound, and it found that there was no difference in the quality of the scar following debridement using the bromelain-based agent versus conventional surgical excision. It also found that early application, in these studies early application was within 12 to 72 hours of the injury is the gold standard. Delays greater than 72 hours should be managed, as I said before, first assuring that there's no infection, and then pre-soaking to soften that eschar before application of the enzyme. It was also found to be effective in reducing the need for an escharotomy if applied early enough. If the compartment syndrome had already become established and there were already high pressures in those compartments, then a surgical escharotomy was indicated. But if the compartments were still somewhat soft, but the patient was noted to be at significant risk of developing one, then application of the bromelain-based enzyme could eliminate the need for that escharotomy. Other studies show that one treatment of four hours, followed by a two-hour soaking, resulted in complete eschar removal of deep partial and full thickness burn wounds. This was a small animal study. Another one showed that after eschar removal, a skin graft should be delayed for two days. That is a recommendation of the consensus panel that presented several of these guidelines.

Advantages

• Less aggressive form of debridement as compared to surgical options
• Faster results than autolytic debridement
  • NexoBrid has faster results than Collagenase, when applied correctly can remove 100% eschar with a single application
• Very selective form of debridement
• Can beneficial and effective adjunct to surgical excision
• Good alternative to surgery in areas that are difficult to deride (deep skin folds, fingers, hands), and areas with cosmetic and functional outcome concerns regarding scar formation (face, neck, hands)
• Collagenase use produces minimal pain
• Collaganase has a simple application, can easily be utilised at the patient bedside, outpatient or home setting

Disadvantages

• Not effective or adequate for severe deep burns or critical patients
• Can cause maceration to periwound tissue
• NexoBrid use requires hospitalization with anesthesia and sedation during use, high risk for pain
• NexoBrid is only appropriate for inpatient use and requires medical doctor/physician's assistant/nurse practitioner to apply and monitor the patient during use, preferably in a Burn Unit or at a Burn Centre
• NexoBrid has a bleeding risk during use
• NexoBrid is approved for application limited to a total body surface area of 15% or less at a time

Conclusion

So non-surgical debridement with a combination of those non-surgical methods can be very effective. It's very common to use a dressing that promotes autolysis and at each dressing change, perform mechanical debridement, and even local sharp debridement to further debride the non-viable tissue and eschar from that burn wound. It's a slower process, but it can be very effective in removing areas of eschar under those smaller dressings. Collagenase can also be combined with an autolytic-type dressing. It's important to remember that that is a daily dressing change, so the dressing you choose should be appropriate for a daily change as far as cost goes and time management, so those Vaseline-coated gauzes in multiple layers that can provide a somewhat occlusive covering will facilitate the work of collagenase much more effectively.

So the biggest benefits for non-surgical debridement include the elimination for the need of a skin graft or a decrease in the size of the skin graft that is needed, which also decreases the size of the donor site. It also allows for ongoing therapy to limit the negative effects of having to immobilise a body part after a skin graft. You can continue with occupational therapy and physical therapy throughout the healing course, which decreases the long-term comorbidities and recovery. The rapid removal of eschar decreases the risk of infection and also decreases the length of hospitalisation. Now, surgery is obviously the most rapid way to remove that eschar, but as I've said with these smaller situations where surgery may not be indicated, the combination of non-surgical debridement interventions can also remove that eschar fairly rapidly and can be done on an outpatient basis if it's a smaller burn and the patient is stable.

So non-surgical debridement has been found to be very safe and effective on smaller burns, management of patients when surgery isn't indicated or not appropriate. Those large burns where they will epithelialise within a three-week time don't necessarily need to go to surgery for any reason, they can be managed locally. Severe hand burns, where the damage from surgery can cause long-term functional problems when they're managed locally with non-surgical interventions, some of those problems can be avoided. And a combination of methods has been found to provide a significant improvement in the efficiency of the non-surgical debridement and the gradual removal of that eschar.

However, in all cases, if the burn has not fully re-epithelialised within 21 days, then most experts agree that a skin graft is essential to limit the comorbidities of allowing that wound to go on and heal secondarily, such as dysfunctional scarring, contractures, and that ongoing risk of infection with that open wound. So in both cases, with these photos, allowing the outer areas to re-epithelialise definitely decreases the area that will need surgical intervention if they don't continue to re-epithelialise completely within that 21-day timeframe.

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