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Debridement: When, How, and Why?
Wound bed preparation starts with achieving an optimal wound healing environment.1-3 Debridement, an initial step in ensuring that optimal environment, is vital in both neonatal and pediatric wound care. Optimal debridement in neonatal and pediatric wounds might be less challenging due to specific healing characteristics and more challenging due to other factors. Debridement often is associated with chronic, poorly healing wounds, which is not a common issue in pediatrics; that is the easier part. The challenge lies in providing safe, selective, and effective debridement without the risk of systemic absorption and toxicity, all while minimizing pain. The types of debridement considered in neonatology and pediatrics are mostly the same as in adult wound care.
SURGICAL DEBRIDEMENT
Surgical debridement often is performed in an operating or procedure room by a credentialed provider, and all devitalized tissue is removed, leaving healthy tissue only. It is selective in experienced hands but may be nonselective in others because a larger wound is often created by the end of the procedure. Surgical debridement is painful, requires anesthesia, and can lead to blood loss and local systemic reaction by the host as, essentially, a new wound is being created. These factors can be tolerated poorly by a patient who is critically ill, immunocompromised, or has comorbidities.
MECHANICAL DEBRIDEMENT
The goal of mechanical debridement is the removal of devitalized tissue, adherent biofilm, surrounding extrapolymeric substance, and a multitude of pro-inflammatory substrates the body produces and releases into the exudate in response to an ongoing wound.1,3 In the past, mechanical debridement often was synonymous with wet-to-dry dressings and scrubbing with gauze. It is likely that this practice has been abandoned in most neonatology and pediatrics practices. The method is nonselective, painful, and injurious to new granulation tissue. In addition, bacteria can spread through the air as they are loosened but not adhering to the gauze.
A monofilament fiber pad and lolly (Debrisoft; Lohmann & Rauscher) has been used successfully to support mechanical debridement in pediatric and neonatal populations.4 This single-use debrider is made of a densely packed and cut-on-an-angle polyester fiber that loosens and absorbs exudate.4 For preterm neonates, cutting a pad in half is sufficient and saves resources. An average session should take 2 to 4 minutes and is, in most cases, tolerated without pain medication. In conjunction with autolytic and enzymatic debriders, this gentle mechanical scrubber allows tissue removal in a short yet effective time frame. The pad/lolly should be wholly saturated in fluid (eg, normal saline) while providing a circular scrubbing motion with gentle, ongoing pressure. Keeping the pad moist decreases the pain and enhances debridement.4 Solutions, such as hypochlorous acid, can be a successful synergistic combination. The antimicrobial nature of the preservative and an acidic pH enhance wound bed readiness for either additional products or granulation tissue growth. Multiple sessions are sometimes required, and enzymatic or autolytic debridement can be used to augment improvement made with the monofilament tool (Figure 1).
Another product, which somewhat fits under the mechanical subheading, is the UltraMIST System (Sanuwave). This provides delivery of low-energy, low-intensity ultrasound to the wound bed through a continuous saline mist. The ultrasound energy helps to lift devitalized tissue.
Hydrotherapy is another method of mechanical debridement, although not really utilized in the pediatric or neonatal populations. In this mode, pressurized saline or water is delivered through a disposable handset. This selective mode can be painful, depending on the pressure delivered to the skin. An additional concern is the potential for bacterial cross-contamination through contact, droplets, and water vapor.
ENZYMATIC DEBRIDEMENT
The only FDA-approved enzymatic debrider in the US (Collagenase Santyl; Smith + Nephew) is an enzyme derived from the fermentation by Clostridium collagenase, a zinc endopeptidase that selectively digests native collagen in the triple helix region in necrotic tissue without any effect on healthy epithelium, keratin, or fibers.5 Collagenase ointment is an excellent stand-alone enzymatic debrider or an adjunct debrider placed on the wound bed to soften the slough before mechanical microfilament fiber use.6 In both pediatric and adult studies, it has shown excellent safety and efficacy profiles.5-8 Studies have shown an increased rate of healing, decreased open wound days, and less pain (although occasionally patients complain of transient erythema). In my clinical practice, I find it effective, safe, and gentle (compared to mechanical scrubbing), yet more aggressive compared to autolytic debriding agents. In my experience, it enhances granulation tissue growth over the wound bed. Studies have now confirmed this finding, suggesting that collagenase creates bioactive collagen byproducts (type 1 and 3) that induce cellular response or signaling of keratinocytes, endothelial cells, and fibroblasts.5,8 I have never seen an adverse local reaction to this product, including many 23-week-old gestation age neonates who have been treated with it. Collagenase is my product of choice for the thick, adhering slough often encountered in severe extravasations or chronic pressure injuries (Figure 2). Cross-hatching the adhering slough with a scalpel enhances eschar penetration.
A dehisced, infected surgical wound is another wound type conducive to collagenase treatment without invasive sharp debridement on recently operated fragile tissue. Collagenase can be inactivated by various chemicals, including iodine, certain silver preparations, and topical antibiotics.6,8
AUTOLYTIC DEBRIDEMENT
Autolytic debridement is tissue removal using the body’s own enzymes. The presence of moisture is paramount for optimal enzyme function. This method is safe, usually not painful, selective, but slow. Various products can be used to augment autolytic debridement.
Hydrogels. Hydrogels are 3-dimensional networks consisting of physically or chemically cross-linked bonds of hydrophilic polymers.9 The insoluble hydrophilic structures can absorb wound exudate and allow oxygen diffusion to accelerate healing. Hydrogels possess a highly hydrated 3-dimensional polymeric network and can bind several-fold more water compared with their dry weight, thereby maintaining a high moisture level of the wound bed.9 Hydrogel-based materials are common dressings to cover skin wounds and to augment autolytic debridement. Furthermore, hydrogels offer a platform to load cells, antibacterial agents, and growth factors. They can enhance extracellular matrix deposition by providing moisture and cell migration. Pure hydrogels do not offer any antimicrobial properties; therefore, I reserve it for a truly clean wound. Whenever there is concern about biofilm presence, colonization, or infection, I opt for an autolytic debrider with an antimicrobial property.
Hydrocolloids. Hydrocolloid wound dressings are wafers, powders, or pastes composed of gelatin, pectin, or carboxymethylcellulose. Absorption capability depends on thickness and composition. The dressings have 2 layers. The inner hydrocolloid adhesive layer has particles that absorb exudate to form a hydrated gel over the wound, creating a moist and insulating environment that promotes healing, protects new tissue, and allows the body’s own enzymes to heal the wound. The outer layer (film, foam, or both) forms a seal to protect the wound from bacterial contamination, foreign debris, urine, and feces; it also maintains a moist environment and helps prevent shearing. Hydrocolloid dressings are designed to be worn for up to a week. Infrequent dressing changes are less disruptive to the wound bed, provided that healthy skin is not compromised. Hydrocolloids are not the dressing of choice in wounds that have significant drainage or in wounds where the surrounding skin is macerated or denuded and is at risk for epidermal stripping.
Medical grade honey (active leptospermum honey [ALH]). Although this multitasker is not marketed as a debrider, many of its properties make it an excellent debriding agent. Hyperosmolar hygroscopic properties increase lymph flow around the wound bed, decrease edema, lift off exudate, promote balance of proteases, and promote increased oxygenation of the viable tissue.10-13 Colonized or infected wounds are known to suffer from basic pH; this in turn attracts bacteria and promotes biofilm formation. ALH is extremely acidic (pH, 3.2–4.2). Acidity helps to modulate acid mantle, decrease bacterial growth, and minimize nutrition available to colonizing organisms, therefore minimizing inflammation. Acidity and increased oxygen diffusion promote fibroblast migration, proliferation, and organization of collagen and angiogenesis.10 ALH supports immunomodulation by upregulation of tumor necrosis factor-alpha, interleukin (IL)-1 beta, IL-6, and prostaglangin E2 from monocytes.10 The ratio of pro- to anti-inflammatory modulators produced by honey may decrease the production of free oxygen radicals. ALH possesses unique antimicrobial properties; on contact with wound exudate, honey’s glucose oxidase produces hydrogen peroxide at a concentration that is just enough to inhibit bacterial growth without compromising new granulation tissue.10,11 Unique phytochemicals (methylglyoxal and alpha-oxoaldehyde) from nectar (Unique Manuka Factor) are active against gram-positive and gram-negative bacteria.10-13 It is one of my favorite multitaskers in the neonatal wound products armamentarium, not necessarily as a debrider but as an overall wound-enhancing solution (Figure 3).
Surfactant-based gel. Concentrated surfactant gel (CSG) forms spherical micelles on the wound bed such that each micelle contains a hydrophilic surface and a hydrophobic core. The hydrophilic surface associates with the wound exudate, facilitates easy mobility in the wound environment, and enables its removal with a simple rinse with water, saline, or commonly used wound cleansers during dressing changes.14-17 The hydrophobic core entraps wound debris and allows for easy removal of trapped debris during rinsing at dressing changes.14-17 An in vitro study has shown the anti-biofilm effect of CSG.15
Another interesting property of CSG is its thermogelling property, owing to the presence of poloxamer 188 (P188).16 P188 enhances temperature-dependent micellar aggregation and a gel-like consistency due to packing together of micelles when the temperature is increased from room temperature to body temperature.14,16 This property helps to retain the gel on the wound bed, ensuring a “stay-put” application. The micelles become more attracted to water in the CSG due to a decrease in ambient temperature during dressing changes; this enables an atraumatic removal of the gel as it becomes softer.
Concentrated surfactant gel “cell-salvage” ability is another intriguing property.17 P188 inserts itself into damaged cell membranes owing to its amphiphilic properties; it also patches breaches in the membrane, thereby salvaging their barrier function. Once the membrane integrity has been restored, this poloxamer is “squeezed out” and excreted in the urine.17 Theoretically, its properties may shorten the inflammatory stage and induce proliferation by increasing gelatinase activity and suppressing excessive collagenase activity. CSG is a product I reach for to debride a wound, reduce neonatal hyperkeratosis, or heal a burn (Figure 4).
BIOLOGIC DEBRIDEMENT
Sterile maggots from larvae have long been used as debriders. Their only target is devitalized tissue, and their work is extremely effective due to the proteolytic enzymes found in their saliva. This method is not used in neonatal care, and I am not aware of any practitioners using this in pediatric care.
SHARP DEBRIDEMENT
Selecting the correct debridement modality and the right agent (if indicated) depend on the wound bed, patient, ongoing comorbidities, and skill/competency of the practitioner. Sharp debridement is not used as often in neonatal or pediatric populations. We avoid anything painful in children as this is one of the most challenging parts of pediatric wound care—gaining the patient’s trust that whatever we do will not cause them pain. In the neonatal world, sharp debridement requires sedation. There is a large body of literature linking poor neurodevelopmental outcomes with sedation/anesthesia administration. There is increased risk of apoptosis/necrosis of oligodendrocytes and macroglia after significant cumulative anesthetics.18,19 Therefore, opiates/sedatives should be avoided unless truly indicated in the neonatal intensive care unit.
CONCLUSION
In my practice, most of the wounds in patients in the neonatal intensive care unit are treated with a combination of an autolytic agent (70%) with or without a mechanical debrider (30–40%); an enzymatic debrider is used in about 30% of these wounds. Microfiber pad and lolly may cause some discomfort, but simple measures such as skin-to-skin, swaddling, pacifier, or sugar solution are effective in eliminating short-lived pain associated with this method of mechanical debridement. Older children tend to tolerate this mode of debridement well, often with the child life specialists, parents, or video devices offering much needed distraction.
Dr. Boyar is director of Neonatal Wound Services, Cohen Children’s Medical Center of New York, New Hyde Park, and associate professor of Pediatrics, Zucker School of Medicine, Hofstra/Northwell, Hempstead, NY. All photos provided are with the consent of the patients’ parents. This article was not subject to the Wound Management & Prevention peer-review process.
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