What You Should Know About Emerging Wound Care Dressings
Selecting the right wound dressing can be challenging given the wide variety of dressings on the market and the different stages of wound healing. Accordingly, these authors discuss an array of modalities ranging from hydrogels and collagen dressings to antimicrobial dressings and the use of advanced adjunctive modalities to help facilitate improved healing.
First of all, it is important to realize that the wound dressing is not the sole factor that heals lower extremity wounds. Debridement, offloading and other proper medical management all play a role in wound healing. The role of the dressing is to provide an optimal environment for that healing to take place. In the field of wound care, you will hear a motto, “it’s not what you put on, but what you take off.” This means that proper offloading (reducing pressure) and wound debridement (removing non-viable tissues) take priority before dressing selection.
The main goal for any wound care clinician is to achieve the fastest wound closure possible. Therefore, matching wound characteristics to the appropriate dressing is the first step to achieving your objective. The condition of each wound will determine the type of dressing best suited for achieving that immediate goal, whether it is exudate management, autolytic debridement, promotion of granulation tissue formation, etc.
Dressing selections can be based on many factors. Wound characteristics change over time and this requires flexibility with dressing selection as well. It is important to keep the dressings organized and minimize the inventory in your facility as most dressings have a shelf life of a few years listed on their sterile packages. One must also consider the cost of the dressing. If one is treating a hospitalized patient, the options for dressings may be limited to what is on the formulary.
Seeing patients in multiple settings and facilities can also present a challenge as one may have to change dressing orders if a patient gets transferred in the middle of treatment. Patients who are in home health situations are often further limited by access to dressings.
Current Insights On Moist Wound Healing And Medicolegal Concerns
It has been proven that a moist wound environment provides the fastest healing.1 However, wet wound beds can harbor bacterial overgrowth. On the other hand, a wound bed that is too dry can lead to tissue desiccation and the wound would not improve. The Cochrane Review, which is a widely available collection of clinical evidence, notes that hydrogels and hydrocolloids that maintained a moist wound environment healed diabetic foot ulcers faster than dry gauze dressing.1
Medicolegally speaking, Krasner and colleagues provide this insight: “National and international wound care guidelines and best practice documents mean that there is no longer a local standard of care. No matter where you practice, you will be held to a national/international standard of wound care practice. Some experts have argued that the selection of the wrong dressing is just as problematic as the administration of the wrong drug and the clinician would be just as liable in a court of law.”2 We second their statement and believe it is indeed malpractice and inappropriate to apply a dry gauze dressing or a “wet-to-dry gauze dressing” to every single wound without assessing the true needs of each patient.
Why The ‘Wet-To-Dry Gauze Dressing’ Is No Longer Acceptable
When it comes to surgery, “wet-to-dry gauze dressing” used to be the gold standard of surgical wound dressing. One would moisten gauze with saline, applying this over an open wound and then removing it forcibly after the gauze dries out. This kind of dressing change often occurs daily.
However, there are many problems with this method. First, this method may be quite painful and it removes anything that adheres to the wound including viable skin and healthy granulation tissue. It often leaves gauze fiber residues behind in the wound, which may be the source of infection or inflammation later. In addition, we know a moist wound environment provides optimal healing and saline-moistened gauze evaporates too quickly to achieve this task. Many experts in the wound care field believe that the wet-to-dry gauze dressing is not a dressing method but rather a crude debridement method that one should reserve only to control grossly contaminated or infected wounds in the short term.
The latest studies have shown that gauze dressings are not a good barrier to bacteria.3 In fact, higher infection rates were present when physicians used gauze dressings to treat chronic wounds in comparison to transparent film dressings. One in-vitro study demonstrated that bacteria can pass through up to 64 layers of dry gauze while moistened gauze is even less effective as a barrier to bacteria.4 Indeed, the emerging evidence demonstrates that the wet-to-dry gauze dressing is no longer considered the best practice as it was in the past.
When Dressings And Topicals Can Provide Additional Debridement
The current best practice of outpatient wound care is to provide sharp debridement at the time of the first visit and repeat it every week as maintenance debridement for the fastest wound closure.5 If additional debridement is necessary between visits or if the wound is too painful for sharp debridement, many clinicians use dressings and topical agents that provide an additional debridement effect.
Hydrogels. These are water-based, jelly-like topical gels that hydrate dry wounds and provide autolytic debridement. Adding moisture to open wounds softens desiccated, necrotic tissues while promoting the enzymes that occur naturally in open wounds. Hydrocolloids have a similar function as a dressing that reacts with wound exudate to maintain the moisture at the wound surface. As we noted previously, there is sufficient evidence that hydrogels and hydrocolloids are effective in healing diabetic foot ulcers.1
Medical-grade honey dressing. MediHoney (Derma Sciences) and other medical-grade honey dressings can be topical debridement agents. These dressings come in various forms such as gel, hydrocolloid and impregnated gauze. Due to the high concentration of sugar, medical honey provides effective yet gentle osmotic debridement by drawing out fluids from the wound bed.6 This special brand of honey is strongly antimicrobial, destroying many of the resistant bacteria found in chronic wounds.
Collagenase ointment. Collagenase (Santyl, Smith and Nephew) is an enzyme naturally found in humans and especially in wounds. By applying collagenase ointment daily, you can debride wounds slowly and gently. In the hospital setting, we often use this product for dry black eschar, which is common in heel pressure ulcers. This agent can be costly since it is a biologic pharmaceutical and expensive to produce.
Maggots. Medical maggots (Monarch Labs) are FDA approved. They are produced and prepared in a sterile environment, and one can apply them over wounds for debridement. These maggots mature quickly so they need quick shipping and immediate application to the wound with a special “cage dressing” as well as replacement every 48 hours. Although maggots are a highly effective debriding tool, we do not use medical-grade maggots routinely because of the high acquisition cost (approximately $100 per one vial) and difficulty of use.
When Are Foam Dressings Appropriate?
Foam dressings are made of polyurethane, which absorbs a large amount of exudate while maintaining the moist wound environment on the wound surface. In comparison, gauze and gauze pads have limited capability in fluid absorption. These foam dressings are appropriate for most open wounds and we use them most often in our wound care center as they allow a wear time up to seven days before needing a dressing change.
Alternatively, alginate is a seaweed-derived material that acts similarly and creates a gel-like substance with wound drainage while holding onto the moisture. Drawtex dressing (SteadMed Medical) is a unique hydroconductive dressing that actively “draws” wound drainage and absorbs it efficiently. One can layer Drawtex dressings on top of one another to increase the fluid absorption.
There are many specialized dressings on the market that are meant for heavier draining wounds. They are much like diapers and contain special polymers that control very large amounts of fluid. Examples include Cutisorb Ultra (BSN Medical). These superabsorbent dressings may be beneficial in terms of longer wear time and comfort for the patient as frequent dressing changes may be painful and costly in terms of the material and labor of daily dressing changes with fewer capable alternatives.
How NPWT Can Bolster Wound Dressings
Negative pressure wound therapy (NPWT) devices can help manage deep or tunneling wounds that have a lot of drainage and require granulation tissue formation to fill the defect. Today, there are many choices for NPWT. The conventional VAC therapy (KCI) offers a rechargeable battery and a large canister that one can use in any open wounds including skin grafts and surgical incisions. Smaller wounds in the ambulatory setting may benefit from new disposable devices that are lighter and smaller, and do not require battery charging. These include the SNaP device (Spiracur) and Pico (Smith and Nephew). These devices may be more appropriate for frail patients with fall risk.
The latest development is instillation NPWT therapy using a specially equipped device, the VAC Ulta (KCI). According to a recent study, the use of instillation NPWT in selected patients facilitated a half-day reduction in operating room visits, a two-day reduction in time to final closure and a four-day reduction in length of stay, equating to a savings of nearly $8,600 per patient.7
What You Should Know About Collagen Dressings And Advanced Biologic Modalities
Collagen is the main component (70 to 80 percent) of human skin and we have numerous collagen dressings to facilitate wound healing by inhibiting matrix metalloproteinases (MMP). Some collagen dressings are combined with other materials such as cellulose to maintain a moist wound surface. Some examples include Puracol (Medline) and Promogran (Systagenix/KCI).
Clinicians can also apply other collagen products much like an artificial skin graft and code and bill them as such. These skin substitute grafts are manufactured from various human and animal collagen sources, including cadaveric human skin (Graftjacket, KCI), human amniotic membrane (EpiFix, MiMedx), bovine (PriMatrix Ag, TEI Biosciences), porcine (Oasis, Smith and Nephew) and many others. At the time of this writing, each skin substitute product has a different Q code for reimbursement.
There are also two biologic “cell therapy” skin substitutes with proven efficacy and safety in large randomized, controlled clinical trials. Apligraf (Organogenesis) and Dermagraft (Organogenesis) are biologically expanded human foreskin cells that are delivered either refrigerated or frozen. We also have one biologic growth factor gel, becaplermin (Regranex, Smith and Nephew), which is a human platelet-derived growth factor. This product is available as a prescription gel that the patient applies daily to the wound bed. Platelet-rich plasma (AutoloGel, Cytomedix), which is produced with a centrifuge using the patient’s own blood, is another product that is now approved and reimbursed for use in chronic wounds.
Comparing Antimicrobial Dressings Versus Regular Sterile Dressings
The conventional wisdom states that if the wound is clean, all you need to use is a sterile dressing. Nonetheless, we are learning more about the existence of wound surface “biofilm” impeding the healing of chronic wounds. It is our opinion that it may be beneficial to use an antimicrobial dressing on most wounds in order to hasten the healing process even when wounds do not show overt clinical signs of infection.
It appears that in order to break down the biofilm over the chronic wound, one would have to combine sharp debridement along with a topical antimicrobial agent or dressing.7 These antimicrobial dressings may reduce the rate of wound infection. However, we have not seen any real-life human data supporting the claim as this particular study would be difficult to design and even more difficult to pass the FDA approval for therapeutic claims.
Exploring The Antimicrobial Dressing Options
There are many different options for antimicrobial dressings. Silver-impregnated dressings and cadexomer iodine (Iodosorb gel and pads, Smith and Nephew) are popular options. The metal ions have an effect of destroying the bacterial cell wall by contact. In our wound care center, we routinely use silver-based dressings such as Mepilex Ag (Molnlycke Health Care) or Aquacel Ag (ConvaTec). As we noted previously, medical-grade manuka honey products have excellent antimicrobial properties and also provide gentle debridement due to their high osmotic concentration of sugar. Clinicians should always be cautious of patients with silver, iodine or honey allergies although such allergies are very rare.
For larger wounds, we often use Cutimed Sorbact WCL wound contact layer dressing (BSN Medical), which in our clinical experience is effective in controlling bacterial burden. It is a non-adherent bacteriostatic contact layer dressing coated with dialkyl-carbamoyl-chloride, a fatty acid derivative that binds to bacteria cell walls and prevents bacterial growth. This product is inexpensive in comparison to silver-containing dressings, non-metallic and not linked to any allergic reaction or bacterial resistance.
Emphasizing The Importance Of Non-Adherent Dressing In Reducing Patient Trauma
We strive to maximize the patient comfort and reduce pain with dressing changes as much as possible. In our wound care center, we use various non-adherent dressings in combination with other absorbent dressings. Petrolatum-impregnated gauze, such as Adaptic (Systagenix) and Xeroform, are inexpensive and widely available across most clinic and hospital settings. Alternatively, one can use Cutimed Sorbact WCL (BSN Medical) when skin maceration is a concern with petrolatum-impregnated gauze.
Mepitel (Molnlycke Health Care) is a plastic mesh dressing with silicone adhesive that may be useful in fixating skin tears, skin grafts or skin substitutes. In general, silicone materials have reduced trauma during dressing removal, facilitate overall comfort and help decrease shearing with pressure ulcers. We use various foam dressings coated with silicone adhesive, including Mepilex and Allevyn Gentle (Smith and Nephew) and others, for treating geriatric patients with atrophic skin instead of conventional acrylic adhesive strips, which may cause further skin trauma.
Pre-medicating with pain medication is another strategy to reduce pain and make the patient encounter more tolerable for the patient’s sake. We provide water and Tylenol to our patients who request them upon their visit to our center. Patients should not pre-medicate with narcotic medication if they drive to your clinic as it may be considered “driving under the influence.”
Dressing removal can be quite painful, especially if the dressing stays on for a long time or there is excess bleeding under the dressing. You can address this situation by saturating the dressing with saline or lidocaine solution for a few minutes. We often inject lidocaine solution into a polyurethane NPWT foam prior to the dressing removal as the granulation tissues tend to get embedded into the foam and cause pain.
Lastly, there are a few clinical studies that demonstrate that applying foam dressings proactively can be effective in preventing pressure ulcers from developing. In one particular randomized study, authors compared a soft multi-layer foam dressing (Mepilex border) applied to the heel versus control in 440 trauma and critically ill patients in an emergency department, maintaining the dressings throughout their ICU stay.8 As a result, there were significantly fewer heel pressure ulcers. In response, at our institution, we use adhesive-bordered dressings on ICU patients’ heels and buttocks as a preventative measure for hospital-acquired pressure ulcers.
Matching the wound characteristics and the appropriate dressing will achieve the fastest wound healing and wound closure. The key is to be flexible and switch the dressing regimen that is most suitable to accomplish moist wound healing as most chronic wounds require a series of different dressings to achieve wound closure. There are a plethora of wound dressings available today. We urge you to select dressings that work the best for you while keeping an open mind as the technology will continue to provide better dressings every year.
Ms. Hakakian is the Director of Research at the University Stem Cell Center at Cedars-Sinai Medical Center in Los Angeles.
Dr. Suzuki is the Medical Director of the Tower Wound Care Center at the Cedars-Sinai Medical Towers. He is also on the medical staff of the Cedars-Sinai Medical Center in Los Angeles and is a Visiting Professor at the Tokyo Medical and Dental University in Tokyo. One can reach Dr. Suzuki via e-mail at Kazu.Suzuki@CSHS.org .
1. Dumville JC, O’Meara S, Deshpande S, Speak K. Hydrogel dressings to promote diabetic foot ulcer healing. Available at http://summaries.cochrane.org/CD009101/hydrogel-dressings-to-promote-dia... . Published July 12, 2013. Accessed June 25, 2014.
2. Krasner DL, Sibbald RG, Woo KY. Wound dressing product selection: a holistic, interprofessional, patient-centered approach. Wound Source: The Kestrel Wound Product Sourcebook. Available at http://www.woundsource.com/wound-dressing-product-selection-white-paper . Published September 2010. Accessed June 25, 2014.
3. Ovington LG. Hanging wet-to-dry dressings out-to-dry. Advances Skin Wound Care. 2002; 15(2):79-84.
4. Lawrence JC. Dressings and wound infection. Am J Surg. 1994; 167:(Suppl 1A):21S-24S.
5. Cardinal M, Eisenbud DE, Armstrong DG, et al. Serial surgical debridement: a retrospective study on clinical outcomes in chronic lower extremity wounds. Wound Repair Regen. 2009; 17(3):306-11.
6. Jull AB, Walker N, Deshpande S. Honey as a topical treatment for wounds. Cochrane Database Syst Rev. 2013;2:CD005083.
7. Kim PJ, Attinger CE, Steinberg JS, et al. The impact of negative-pressure wound therapy with instillation compared with standard negative-pressure wound therapy: a retrospective, historical, cohort, controlled study. Plast Reconstr Surg. 2014;133(3):709-16.
8. Santamaria N, Gerdtz M, Sage S, et al. A Randomised controlled trial of the effectiveness of soft silicone multi-layered foam dressings in prevention of sacral and heel pressure ulcers in trauma and critically ill patients; the border trial. Int Wound J. Epub ahead of print.