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Wound Care Q&A

How To Handle Black Eschar Formation

Many leading researchers and wound care practitioners have shown that one of the most important elements in treating wounds is performing regular debridement of tissue (such as eschar) which interferes with wound healing. Timothy Shea, DPM, says the standard approach is to initially debride eschar (and other non-viable tissue) until you get down to good viable tissue and do subsequent debridement every seven to 10 days until you see good granulation tissue.
But what about the presence of black eschar? According to Alexander Reyzelman, DPM, there is a bit of controversy over whether you should debride black eschar or leave it alone. Dr. Shea notes that eschar formation is more problematic when you’re treating patients who have underlying diseases (i.e. diabetes, immunological deficiencies) or have conditions (arterial or venous disease) which inhibit the normal phases of wound healing.
“In these wounds, the inflammatory process is delayed, leading to a buildup of eschar, which then interferes with the proliferative phase and leads to the creation of a chronic wound,” explains Dr. Shea.
With these issues in mind, our expert panelists discuss what goes into their decision-making when determining how to handle black eschar.

Q: Does the location of the eschar alter your decision to debride?
A: Dr. Shea says it is important to consider the location of the wound as it relates to underlying tissue, such as subcutaneous fat, ligaments, tendons and bone. If you are going to be debriding areas such as the heel or under the metatarsals, Dr. Shea says it is common to debride as far as bone and remove some of the bone as well.
“The important factor to remember here is to be more aggressive than conservative,” he advises. “If you are not aggressive enough, you will leave behind non-viable tissue and will eventually have to go back in and remove it later.”
While location does not play as big a role as the clinical appearance and cause of the eschar in their decision-making, Dr. Reyzelman and Suhad Hadi, DPM, say they are more “cautious” about heel eschars. Once the heel develops an eschar, Dr. Reyzelman points out that there is not much protecting the calcaneus except the avascular subcutaneous fat and fascia. He warns that heel ulcerations and eschars “frequently” lead to partial/total calcanectomies or a proximal leg amputation.

Dr. Hadi adds that when eschar is solely caused by an area of pressure (such as a heel pressure ulcer), it is strictly due to focal pressure necrosis. She says you can often offload these areas and the eschar will slough in time, leaving behind an epithelialized region, which avoids the creation of an ulcer.
However, when the eschar is related to a degree of vascular compromise (based upon your clinical findings), Dr. Hadi emphasizes leaving the eschar alone. In order to test eschar and its relation to vascular compromise, Dr. Hadi recommends debriding the periphery of the eschar to visible wound margins and following the patient within a week. If there is associated vascular compromise, Dr. Hadi says you will see the eschar reform. If there is no vascular compromise, you’ll see epithelialization of the debrided region.
If the eschar is freely mobile, loose, separates from the underlying tissue, has a foul odor or purulent exudates, Drs. Reyzelman and Hadi say you should suspect an underlying infection and proceed to immediately debride the eschar. If you see that the eschar has a “wet and soupy” presentation, Dr. Reyzelman recommends immediate debridement.
However, if your patient has dry black eschar that is well adhered to the underlying subcutaneous tissue, you should leave the eschar alone, according to Dr. Reyzelman. With time, he says you’ll see the edges of the eschar begin to lift away from the newly formed epithelial tissue. At this time, you can debride the loose edges while leaving the rest of the eschar alone. He emphasizes that dry black eschar implies a “significant component of peripheral arterial occlusive disease” and may necessitate further arterial workup. Debriding these eschars will expose subcutaneous fat, which increases the risk of desiccation and the development of deep infection, points out Dr. Reyzelman.

Q: Are you concerned that by debriding the eschar, you may create a deeper wound that could get infected?
A: Dr. Hadi says this is not a deciding factor on whether she’ll debride eschar. If you do debride eschar and create a wound, she maintains that appropriate wound care should “help minimize contamination and ultimately infection of the wound.”
To that end, Dr. Shea says you can reduce this concern by using aseptic technique; controlling the wound environment locally and systemically; and closely monitoring the wound healing process (by measuring the wound volume and surrounding tissue status) weekly until the wound has closed over adequately. On average, you’ll see a 50 percent reduction in wound volume within eight to 10 weeks and 100 percent closure within 16 to 20 weeks, according to Dr. Shea.
“With aggressive algorithmic wound care, wound healing time frames such as these (even in the most compromised patient) occur 85 to 90 percent of the time,” maintains Dr. Shea.
As he mentioned above, Dr. Reyzelman is mostly concerned about exposing the subcutaneous fat. “Since the fat is avascular and this area is poorly perfused, the fat starts to dry out and eventually will require debridement,” explains Dr. Reyzelman. He adds that in patients with more severe peripheral arterial occlusive disease, debridement of the eschar will quickly lead to another eschar.

Q: Are you concerned about arterial perfusion when you see black eschar formation?
A: Adequate arterial perfusion is essential to the process of wound healing and the presence of persistent eschar indicates poor arterial flow to an area, notes Dr. Shea. He says this could be the result of underlying vascular problems, like arterial sclerosis or stenosis, or pressure issues which DPMs often see in decubitus-type wounds.
Dr. Shea says you obviously want to address these issues, whether it’s by altering the pressure status via offloading or increasing perfusion by medical, interventional radiology or surgical means. Combining the clinical evaluation of the patient’s vascular status (physical exam) with ancillary testing (Doppler, TCPO2, TCOM, segmental vascular non-invasive testing, and arteriography with or without angioplasty) is essential for determining the timing and extent of eschar debridement, according to Dr. Shea.
When he evaluates patients who have black eschars, Dr. Reyzelman always performs a more advanced arterial exam. He says he frequently obtains a non-invasive arterial study to get a better appreciation of the severity of arterial occlusive disease. On many occasions, Dr. Reyzelman will refer patients with black eschars to a vascular surgeon for a bypass. After the revascularization, Dr. Reyzelman says the eschar will frequently become wet and he then performs a debridement.

Dr. Reyzelman (shown on the right) is Chairman of the Department of Medicine at the California College of Podiatric Medicine (CCPM) and has a private practice in San Francisco.

Dr. Hadi is an Assistant Professor and the Director of Resident Education at the University of Texas Health Science Center in San Antonio, Texas.

Dr. Shea is a Certified Wound Care Specialist at the John Muir Wound Care Center in Walnut Creek, Calif., is an Adjunct Associate Professor at CCPM and has a private practice in Concord, Calif.

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