Wound Series Part 2c: Wound Bed Cleansing

This wound care course serves as a continuation of the course series, Wound Series 2b: Wound Care, but it also can be taken alone for those interested in refreshing their knowledge and skills of the process of proper wound bed cleansing. This course will go over pain management considerations prior to wound cleansing and debridement, a brief review of the TIME/TIMES mnemonic from the prior course (Wound Series 2b: Wound Care), a more in-depth breakdown of this mnemonic to emphasize common debridement methods and how to differentiate inflammation of a wound versus an active infection and an explanation of how to determine when it is appropriate to utilize antimicrobial wound cleansing solutions versus less cytotoxic methods.

The Joint Commission (Joint Commission for Accreditation of Health Care Organizations [JCAHO], 2017) lists pain management as a quality indicator for acute care settings. Basic pain management includes an accurate assessment and documentation of wound pain. While pain management may be addressed most in burn wound settings, it is increasingly addressed in other chronic wounds (and rightly so!), as especially prior to wound cleansing and dressing changes.

The gold standard for an accurate assessment of the patient's pain is a self-reported pain level. Whether a pain scale of 0 (no pain) to 10 (excruciating pain) is used, or smiling faces/grimacing faces, the pain level should be documented exactly as the patient reports it. The onset, location of the pain, and the quality of pain (stabbing, shooting, throbbing, sharp, dull, constant or intermittent, intensity) along with what factors relieve the pain or make the pain worse (walking, standing, elevating the leg, etc.) should be ascertained and documented. The pain effects on the patient and any pain management history and current pain regimen should also be determined. Also, determine the patient's pain management goals (Sibbald et al., 2021).

Worsening wound pain is one hallmark of a deteriorating wound. It may indicate infection than other observable signs such as edema, warmth, and erythema surrounding chronic wounds. Woo and Sibbald developed a Chronic Wound Associated Pain (WAP) model (Krasner, 2014) to address the patient, the cause, and the wound. This algorithm may help determine an evidence-based approach to wound pain management. Persistent chronic pain is highly individualized and requires highly specialized medical care. If wound-related pain is not well managed, patients should be referred to specialists to address their wound pain. Persistent or chronic pain itself may impair wound healing by causing vasoconstriction and decreasing perfusion, so every attempt should be made to address chronic wound pain (Sibbald et al., 2021).

Pain with wound cleansing and dressing changes may be managed by topical anesthetic products such as 2% or 4% topical Lidocaine Jelly or EMLA cream or systemic medications such as NSAIDs or opioids. Topical anesthetics (Lidocaine, Prilocaine, etc.) should be applied with enough time before debridement or dressing change for the medication to take effect (approximately 10 min). Similarly, the systemic pain medication should also be administered to allow enough time for pain relief prior to starting (at least 30 minutes).

Addressing the pain when an infection is suspected would include addressing the infection. Certain wound products may assist with pain management in specific types of wounds. Matrix applications using small intestine submucosa (SIS) technology (typically porcine) have successfully relieved some wound pain, particularly over donor sites from split-thickness skin grafts. Glycerin or silicone-based gel sheets and hydrogel sheets (cross-linked polyethylene oxide and water) such as Vigilon may be cool and soothing to partial thickness wounds such as second-degree burns silicone helps reduce scarring after wound closure. Be on the alert for new, different (especially worsening), or persistent pain associated with chronic wounds. Persistent pain in a neuropathic extremity with a chronic wound may be associated with osteomyelitis (Baranoski & Ayello, 2020).

As introduced in the previous course in this wound series, Wound Series Part 2b: Wound Care, the TIME mnemonic is valuable for individuals participating in wound care. This wound bed preparation concept describes a systematic approach to addressing the wound bed's specific needs in full-thickness open wounds (Sibbald et al., 2021; Doughty & McNichol, 2015).

Evidence-based literature describes this mnemonic, T-I-M-E, to help clinicians perform evidence-based wound care (Gupta et al., 2017).

"Cleansing" the wound should not only address washing or rinsing a wound but also includes debridement or addressing the removal of non-viable or devitalized (necrotic) tissue from the wound bed as part of the 1st step in the TIME approach to wound management (Gupta et al., 2017).

Types of cleansing or debridement approaches should be based on a holistic approach to wound management, including the specific condition(s) of the wound (and patient), the established goals of treatment, and patient preferences (if possible) (Sibbald et al., 2021).

Necrotic tissue is a breeding ground for bacteria. It impairs wound healing (e.g., impairs optimal cellular communication and proliferation and acts as a physiological barrier to new tissue deposition and wound contraction) (Willy, 2013; Maheswary et al., 2021; Sibbald et al., 2021). Removing this unhealthy tissue (debridement) may be achieved by a variety of means (Salisbury & Percival, 2018; Maheswary et al., 2021; Sibbald et al., 2021):

1. Sharp debridement, either selective or non-selective (with a scalpel, scissors, curette)
2. Surfactants
3. Enzymatic (collagenase ointment or similar)
4. Autolytic (promoting the body's enzymatic activities)
5. Mechanical (rough friction or wet-to-dry)
6. Irrigation (including surgical water jet)
7. Biosurgical or larval debridement (medical maggots)

In almost all cases, necrotic tissue should be removed when safely possible. This removal includes (Maheswary et al., 2021):

• Slough (white, yellow, grey "chicken fat" appearing tissue)
• Fibrin (adherent, white-yellow, or grey fibrous non-viable tissue)
• Eschar (typically thick, brown to black, "leathery" dead tissue)

There are a few exceptions to this rule. One important exception is in the case of intact, hard, black eschar, such as on the foot's heel, without any signs of infection. There is no way to determine the depth of tissue damage underneath this eschar. Removing it may expose the bone and predispose the patient to infection and osteomyelitis. "Intact" is the keyword here. If this eschar is dry, NOT soft, boggy, or fluctuant, and does not have any lifting at any of the wound edges or drainage, it may be beneficial to leave this eschar alone. Of course, pressure should be offloaded from the area, and the eschar should be kept clean and dry (Doughty & McNichol, 2015).

Another exception is dry eschar in a person with advanced lower extremity arterial disease. Cover the eschar with dry gauze for protection and (if not contraindicated) "paint" it daily with a small amount of 10% povidone-iodine solution (commonly known as Betadine solution, providing 1% available Iodine) and let it air dry thoroughly before applying dry gauze for protection and padding (Gupta et al., 2017). With this tissue in place, it may act as a protective "body bandage" – keeping bacteria and contaminants out of the wound. Under this eschar, the wound healing process may continue if other wound healing impediments are addressed (offloading pressure, adequate nutrition & blood flow, adequate immune function, and tissue perfusion). If the wound under the eschar follows a healing trajectory, the eschar may lift itself after several weeks and display newly epithelialized skin underneath. In some cases, the eschar may lift prematurely at an edge or start feeling boggy or fluctuant underneath the eschar and may start draining or showing signs of infection. It may be best to remove the eschar (Sibbald et al., 2020).

One of the main functions of a wound dressing or wound therapy is moisture management. Specifically, maintaining a moist wound bed while also eliminating excessive wound drainage. Since George Winter's seminal work in 1962 (Winter, 1962) demonstrated open wounds treated with dressings that maintained a moist environment healed almost 50% faster than wounds allowed to dry out, no published studies have been able to refute the effectiveness of moist wound healing. Current scientific investigations not only support what has been known about moist wound healing but serve to explain further the role of a moist wound bed in relation to the local cellular activity associated with wound healing (cytokine signaling, fibroblast cell proliferation, collagen and matrix synthesis, epithelial cell migration, etc.) and preventing additional trauma from wounding bed during dressing changes (Ermer-Seltun & Rolstad, 2016; Jaszarowski & Murphree, 2016).

Assessment (and documentation of the wound edges) is important for wound care. Rounded, "rolled" wound edges can prevent epidermal cell migration, ultimately impairing wound contraction and closure. Tracking or tunneling in the wound bed and undermining (a 'lip' or ledge under the wound edge) may also impair healing. Undermining is often caused by shearing forces upon the wound area, frequently seen in pressure ulcers around the sacral area, such as when the patient is repeatedly sliding down while attempting to sit up in the bed (Sibbald, 2021). In these cases, the potential cause needs to be considered (such as shearing forces) and eliminated where possible. In the case of a "rolled" wound edge, it may be necessary for surgical intervention or chemical cauterization (such as with silver nitrate sticks) by a qualified specialist.

The condition of the skin and tissue surrounding the open wound should be examined and palpated for (Gupta et al., 2017):

• Pain/tenderness
• Induration
• Unusual warmth or coolness (different from the skin on the same extremity at a different location)
• Maceration
• New or satellite areas of erythema
• Rash
• Dryness
• Scaling
• Thickening
• Bogginess
• Crepitus
• Bruising
• Skin lightness or darkness compared to the patient's skin tone
• Blistering
• Hyperkeratotic tissue

These findings should be reported/documented and monitored at each wound care visit (Gupta et al., 2017).

Now that you have completely pre-medicated for pain completed a full wound assessment for inflammation versus infection, and collected any necessary tissue samples, you are ready to clean/debride the wound before dressing it.

Many experts agree that it is necessary to cleanse wounds at each dressing change to remove wound exudates, cellular waste, debris, bacteria, etc. (Doughty & McNichol, 2015). However, caution is warranted regarding the use of antimicrobial wound cleansers.

Cytotoxicity relates to a substance being toxic to human tissue cells. Cytotoxic wound cleansers will kill germs and kill healthy cells such as fibroblasts (white blood cells that manufacture collagen/new tissue) or epidermal keratinocytes (skin cells) (Doughty & McNichol, 2015). Also, many of these cleansers are antimitotic (they actually prevent cellular mitosis and regeneration), which is how some chemotherapy agents function to prevent cancer cell growth. While that may be a desirable trait for cancer treatment, it may not be desirable for a wound cleanser!

In most cases, wound experts recommend using water or saline to cleanse the wound. Some articles suggest potable tap water may be appropriate to cleanse chronic wounds (Sibbald et al., 2021). However, it has been concluded that the decision to use tap water to cleanse wounds should consider the quality of water, the nature of the wounds, and the patient's general condition, including the presence of comorbid conditions (Gupta et al., 2017; Doughty & McNichol, 2015). Water must be potable for tap water to be considered for wound cleansing. Caution may be warranted for several reasons when considering tap water. It is not known if the water used for wound cleansing vs. normal saline was tested for bacteria, cysts, fungi, or the presence of any other contaminants. If obtained from a well, tap water may contain contaminants such as bacteria or other contaminants undetectable to the human eye. Alternatively, "city water" is typically chlorinated at around three parts per million or 0.3mg/L and also typically contains fluoride (0.5mg/L to 1.0mg/L). Therefore, it is unknown what effect this may have on cellular activity in the wound bed (Gupta et al., 2017; Doughty & McNichol, 2015).

An exception to using cytotoxic wound cleansers is when the benefits outweigh the risks. For instance, in the case of localized bacterial invasion in which the host is unable to overcome the bioburden of the infecting organism(s) with its immune defenses (such as pseudomonas aeruginosa infection resulting in further wound deterioration), the fibroblasts and epidermal keratinocytes are not likely to survive this hostile wound environment anyway. Therefore, it may justify using a short-term application of cytotoxic wound cleanser, such as a dilute Dakin's Solution (sodium hypochlorite), long enough to eradicate the infecting organisms (Gupta et al., 2017; Doughty & McNichol, 2015). Yes, this is likely to impair cellular function temporarily. Still, the infecting organisms would do far worse if you did not address/control them. Once the wound is "cleaned up" (perhaps for even a few weeks), you should return to non-cytotoxic moist wound healing principles for wound care.

Dakin’s Solution is a long-used cleansing solution that is used to kill bacteria and prevent bacterial growth in wounds (Keyes et al., 2022). It is a dilute sodium hypochlorite (NaClO) solution, more commonly referred to as “bleach” (Keyes et al., 2022). The main active ingredient in Dakin’s Solution is created when the chlorine in the solution reacts with water to form hypochlorous acid (HClO) (Keyes et al., 2022). It is this hypochlorous acid that produces an antibacterial effect in tissues (Keyes et al., 2022).

Ohio State University Medical Center (OSUMC) Department of Inpatient Nursing published a nice patient education pamphlet, "How to Make Dakin's Solution," available here. (Ohio State University Medical Center [OSUMC], 2002).

This pamphlet describes diluting 3 ounces of common (unscented) household bleach (5.25% sodium hypochlorite solution) with 32 ounces of clean, boiled water (buffered with ½ teaspoon baking soda/sodium bicarbonate) to make a full-strength Dakin's Solution (0.5% sodium hypochlorite solution).

To make ½ strength Dakin's Solution (0.25% sodium hypochlorite), use only 3 tablespoons (48ml) bleach mixed with the same amount of water (32 ounces) and baking soda (1/2 tsp). OSUMC reports tightly sealed jars of these solutions may be stored at room temperature for up to one month (in a dark jar), but once opened, any unused solution should be discarded within 48 hours.

Many clinicians are misinformed about Dakin's solution, specifically regarding when to use and not to use it, solution storage, documentation, and cytotoxic versus non-cytotoxic strengths. Here are some things every clinician should know about Dakin's:

1. As described above, full strength Dakin's Solution is a 0.5% sodium chlorite (hypochlorous acid) solution. Most are buffered with sodium bicarbonate to bring the pH up to one more easily tolerated by human tissues.
2. Dakin's Solution is cytotoxic at full strength, half strength, quarter strength (0.125% sodium hypochlorite), and even one-eighth strength (0.0625% sodium hypochlorite) fibroblasts and keratinocytes. Full strength Dakin's Solution would need to be diluted 50 times (one-fiftieth dilution) to reach a 0.01% sodium hypochlorite solution (a non-cytotoxic strength).
3. Clinicians should ask:
   1. What strength was ordered?
   2. Is this strength appropriate?
   3. Is it ordered short-term or long-term? (Short-term use of quarter-strength Dakin’s may be appropriate to address a high localized bioburden because the benefits may outweigh the risks).
4. Documentation of the use of any sodium hypochlorite solution should always be done by recording the exact strength used. Many times, all strengths are just recorded as "Dakin's Solution," but this is, in effect, the same as documenting that insulin was given without recording the exact strength. Dakin's Solution is a 0.5% sodium hypochlorite solution and is often diluted because of its high cytotoxic properties. Make sure to RECORD the correct strength!!!

A chart called "Know the Code" describes the different dilutions of sodium hypochlorite solution is available here. (Century Pharmaceuticals, n.d.).

Common side effects of Dakin’s Solution are necessary to know for patient safety. These side effects include swelling, redness, and local skin irritation (Keyes et al., 2022). Additional concerns regarding Dakin’s include skin hypersensitivity, allergic reactions, and impaired wound healing (Keyes et al., 2022). If there appears to be an adverse reaction occurring after the introduction of Dakin’s Solution, it should be discontinued immediately (Keyes et al., 2022).

This course covered pain management considerations prior to wound cleansing and debridement, a brief review of the TIME mnemonic, a more in-depth breakdown of this mnemonic to emphasize common debridement methods and how to differentiate inflammation of a wound versus an active infection, and an explanation of how to determine when it is appropriate to utilize antimicrobial wound cleansing solutions versus less cytotoxic methods. For more information regarding wound dressings, please continue forth within the wound care series to Wound Series Part 2d: Wound Dressings.

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