Susan Mendez-Eastman is certified in both wound care and plastic surgical nursing. She has served four years as a Surgical First Assistant at Omaha's Plastic Surgical Center, and is a research nurse for the University of Nebraska Medical Center College of Nursing. Eastman maintains independent practice privileges at several Omaha health systems. She is also a wound care nurse for the Nebraska Health System Center for Wound Healing. She received her ASN degree in nursing from Metropolitan Community College of Omaha, Nebraska.
Eastman's professional dedication is pervasive. She serves as continuing education coordinator for the American Society of Plastic and Reconstructive Nurses in addition to performing legal case reviews in the area of wound care. She has delivered some thirty conference presentations and is the author of over a dozen medical articles on wound therapy.
Eastman spoke recently with Wounds1 about an important technological advance in the centuries-old practice of wound therapy.
Wounds1: Let's start with the basic definition - what is a wound?
Eastman: A wound is basically defined as any break in the integrity of the skin. There are two primary categories of wound - acute and chronic.
An acute wound is one that follows a normal process of healing. For example, if a healthy individual breaks a bone and the physician sets it and protects it with a cast, the natural healing process is expected to take over from there.
An acute wound can be surgical (that is, a planned intervention), or traumatic (for example, caused by an accident).
A chronic wound is one that does not proceed through the normal stages of healing. There are many different factors that can alter the normal healing process, including chronic illnesses, poor vascular flow, and infections.
If I had to categorize the three most common types of chronic wounds, they would be pressure ulcers, neuropathic ulcers, and vascular ulcers. These categories do not cover all chronic wounds, but represent the majority.
Those of the first type, pressure ulcers (or pressure sores), are sometimes incorrectly referred to as bedsores. The term “bed sore” leads one to believe that a bed caused the ulcer when it is actually initiated and exacerbated by unrelieved, prolonged pressure. Other synonyms are pressure wounds, decubitus ulcers, or dermal ulcers. These wounds are caused when the skin and/or underlying tissues are damaged by sustained, unrelieved pressure on part of the body, often a bony prominence. This is most likely to occur in a compromised patient (unable to respond normally).
A common cause of pressure could be the body's own weight as it lies on a bed or sits in a chair for a period of time. Normally your body is automatically going to sense when you should relieve excessive pressure by stimulating a shift in body positioning. But a paraplegic, for example, can't feel the pressure, and could not respond by moving even if she or he could feel pain.
You can also get pressure ulcers from wearing a cast or an appliance.
The second type of chronic wound is a diabetic or neuropathic ulcer. Neuropathy is a multi-faceted nervous-system impairment that often accompanies diabetes and can often cause a loss of sensation in the patient's feet and/or lower extremities. Loss of sensation allows undetected pressure that can result in serious ulceration. Many other factors related to diabetes complicate the treatment of a diabetic ulcer.
The third category of chronic wounds is the vascular type, caused by deficient blood flow - a lack of venous return or arterial flow, or a combination of both.
To me - in spite of all this scientific classification - the most important principle of wound care is that every person is an individual and that each wound has unique properties. Although you may be able to place a wound into one of the above categories, it is important not to generalize, because there are likely multiple causative factors contributing to a wound that fails to heal.
Wounds1: One of your contributions to the medical literature is titled "A Glimpse into the History of Wound Care." How would you summarize that history?
Eastman: In that article I tried to compare trends in wound care. Many of the practices throughout the centuries have come full circle – proving to be scientifically sound by today’s standards. In ancient Egyptian practice, which was surprisingly modern for its time, they treated many wounds with honey and oil. Modern medicine has revealed that honey does have some antibacterial properties and oil kept the wounds moist. So, with that said, the history of wound care includes many variations on the same types of treatments. History does repeat itself through the ages; the proven traditional remedies come back to us with modern names and marketing programs, and hopefully scientific evidence of efficacy.
In many ways wound healing is still a relatively new science. During the World Wars, if a patient's wound on the arm or leg were grossly infected, the limb would likely have to be amputated. Your body wants to heal itself at all costs. It wants to get that wound closed, even at the cost of your life. As recently as World War II, science did not fully understand the nature of chronic wounds and had not found appropriate ways to intervene and support healing of a complex chronic wound. Folk wisdom was to dry the wound out. Our mothers told us to let the sun and air get to it, but science has sense proven that this is the wrong thing to do.
Around the 1960s, researchers found that moist wound healing is the best practice in wound care. Providing a moist environment, neither wet nor dry, is particularly conducive to good healing. By the 1970s and 1980s, moist wound healing was widely adopted by specialists. But even today, unfortunately, it is not universal practice. You'll still find people using sun lamps and wet-to-dry dressings to dry the wound out.
The moist environment provides a venue for tissue regrowth, and that is necessary for success in wound healing. With a full-thickness wound (penetrating through all layers of the skin), you have to have new blood vessels form across the defect (open space). The gap has to be filled with granulation tissue, which is a combination of fibrin, collagen, and tiny blood vessels. Once filled with granulation tissue, a scar can form to close the wound. If the defect is too large, a skin graft or tissue transfer may be considered to speed up the closure process.
A partial-thickness wound leaves some skin cells intact, and these can regenerate over time, with little or no scarring. However, you will always have a scar if the wound has penetrated all layers of the skin and the dermal cells are destroyed. This is natural.
Wounds1: If wound therapy is in many respects a new science still seeking the best practices, does traditional technique have value?
Eastman: Certainly. For chronic wounds, traditionally, you have to find out what is preventing the wound from healing, and correct these problems when possible. Sometimes it is not possible, for example, when a venous stasis ulcer results from incompetent valves that allow un-oxygenated blood to pool in the lower extremities rather than being returned upward. When the blood pools, it begins to break down and leak out through the vessels' walls. This process then irritates the tissues and begins to form a stasis ulcer.
Traditionally, we ask, what can we do to repair the faulty venous system? Typically the surgical options are limited. Compression therapy is a traditional approach, applying graduated minimal pressure from the toes to the knees, where the larger veins can take over. Compression, along with the bodies muscular system aids blood return and reduces swelling.
But in some cases compression is not appropriate. We can't use it to correct arterial flow; in fact compression therapy is usually contraindicated with arterial insufficiency. With an arterial wound re-vascularization is the most commonly considered intervention. Arterial bypass surgery is a major procedure and carries with it surgical risks and no guarantees for wound healing.
Even the newer technologies for wound care often go back to the basic question of blood flow. With a venous stasis ulcer, for example, new technology focuses on how we can provide compression more consistently and comfortably for the patient. Wearing the traditional elastic wraps 24 hours a day is very difficult for an ambulatory patient. Layered compression system and prescriptive gradient stockings have offered alternatives for this group of patients. More and more, wound care specialists try to diagnose the underlying problem that caused the wound in the first place and then try to intervene in the best way possible. If the underlying problems can be fixed, or supported, the wound will likely heal.
Wounds1: Let's talk about a new technology that you advocate in wound care - negative pressure wound therapy.
Eastman: I am very much an advocate of negative pressure wound therapy. When I first started working for the Wound Center, negative pressure therapy had just been introduced in the Midwest, and it was my responsibility to teach the staff the appropriate use and benefits of this therapy. To do that, I felt I needed to understand it very thoroughly myself. I found, and continue to believe, that it is a minimally invasive, cost effective wound care modality. It was different than anything I had used before, as it was dynamic and multi-faceted compared to the topical dressings and ointments I was accustomed to. Negative pressure wound therapy is certainly not for every wound, but in my opinion, it has opened up a whole new avenue in wound care.
Wounds1: What is negative pressure wound therapy?
Eastman: Negative pressure wound therapy is controlled suction, which is applied to a wound in order to stimulate healing. By applying controlled negative pressure to a wound excessive fluids are removed, cells are stimulated to proliferate, angiogenesis is accelerated, and the sustained contraction helps to draw the wound closed. As we discussed earlier, this is another therapy has it’s roots in the very distant past. Ancient Egyptian practitioners used a similar form of suction to draw toxins out of wounds. They placed an inverted cup over the wound and heated the air inside the cup with a candle. This warmed trapped air likely provided modest negative pressure to the area under the cup.
Negative pressure wound therapy has been proven effective in both chronic and acute wounds, but, like any therapy or treatment, is not indicated for every wound. As I always emphasize, every person and every wound is unique.
Wounds1: How does the technique work?
Eastman: Negative Pressure Wound Therapy utilizes a reticulated sponge, a form that distributes pressure evenly throughout the sponge regardless of where the suction is applied. We cut the sponge to fit the size and depth of the wound. We fill the wound with this sponge, cover the area with a semi occlusive clear drape, and connect the wound via a tube to a canister that is attached to the computer-controlled unit that applies the programmed suction. The system gently pulls stagnant fluids, such as wound drainage or stagnant fluid surrounding the wound and evacuates it through the tube and collects the fluids inside the sealed canister.
Wounds1: Is "V.A.C.® therapy" the same as negative pressure wound therapy?
Eastman: V.A.C.® stands for Vacuum Assisted Closure, the trademark for the negative pressure wound therapy system developed by KCI, a Texas-based company.
Wounds1: What are the advantages of this new technology?
Eastman: Negative pressure wound therapy does several things to stimulate wound healing. The five major benefits of this therapy are, briefly, as follows:Protection. By placing the semi-occlusive drape over the open wound, you have created a “closed wound environment”. This is beneficial in that it protects the wound from external contaminants. This also helps protect other patients and staff from potential cross contamination. Negative Pressure Wound Therapy dressing changes are usually done every 48 hours – we do our dressing changes in the hospital every Monday, Wednesday, and Friday. The decreased number of dressing changes further decreases the risk of cross-contamination. Because the clear drape is semi-permeable, it allows gaseous exchange – this is important in a wound that is or potentially could become infected with anaerobic organisms.
Blood Flow. Negative pressure wound therapy supports blood flow to the wound bed. Adequate blood flow supports a moist wound environment. Many wounds develop a zone of stasis, or stagnant wound fluid, around the wound. This fluid can prevent blood from reaching the defect. By applying controlled negative pressure that helps to alleviate this redundant fluid, blood can flow into the wound bed. Negative pressure, when applied at appropriate levels, can also enhance angiogenesis, the development of new capillaries, that supply the wound bed with the healing properties that only blood can provide – such as oxygen, white blood cells, and nutrients. Negative pressure wound therapy will not re-vascularize a patient. It will, however, assist circulation to the wound bed by removing obstacles such as stagnant fluid.
Decreases bacterial load. By removing stagnant wound fluid, which is a fantastic medium for organisms, you reduce the bacterial load. In addition, negative pressure wound therapy also enhances infection control by supporting blood flow, which is a vital aspect for fighting infection.
Increased proliferation. Controlled negative pressure actually helps the wound get smaller faster. As the foam dressing contracts, the tissue cells are stretched, which encourages them to multiply. Research has proven that mechanically stretching cells encourages them to proliferate at an increased rate. A cell wants to be round and buoyant. If stretched and irritated, the cell divides so it can resume it’s normal shape. Continued irritation, via negative pressure, can increase the rate of tissue re-growth dramatically.
Wound Contraction. The mechanisms in place during negative pressure wound therapy speed the rate of wound contraction. When negative pressure is applied to the wound, it contracts. This contraction is supported during the therapy, much like a brace or splint. As the dynamics within the wound enhance healing, contraction is also accelerated.
Negative pressure therapy offers a considerable advantage in terms of patient care. Instead of putting patients through the traditional changing of moist saline dressings 4-6 times every day, we need dressing changes only 3 times a week. We gain a more efficient use of staffing resources, and you can't put a price on the increased comfort to the patient.
Wounds1: Does the patient choose this new therapy?
Eastman: I'm a huge patient advocate – it's always their choice. If the health care team believe the patient is an appropriate candidate for negative pressure wound therapy, and the patient is offered the choice, they will generally choose V.A.C.® therapy once it has been explained to them, since it minimizes their dressing changes, it usually reduces pain because it compresses and covers exposed and irritated nerves, and the overall time that they will be laid up is likely to be reduced.
Wounds1: How is the V.A.C.® system typically incorporated into wound treatment?
Eastman: First, the patient and wound must be evaluated to determine if V.A.C.® therapy is an appropriate treatment modality. In the case of a patient who comes in with a venous stasis ulcer, we want to optimize the wound bed with a likely plan to skin graft for closure. Venous stasis ulcers generally occur in an area that has little stretch, and therefore, unlikely to close by secondary intention. By applying V.A.C.® therapy prior to skin grafting, the wound is “beefed” up. V.A.C.® therapy will reduce the bacterial load; reduce any stagnant fluid surrounding the wound, and support blood flow, thus making it a prime bed for the skin graft. So we will use the V.A.C.® system on the wound for 3-5 days prior to surgery, to draw out excess fluid and prepare the bed for grafting. The surgeon that I work for routinely places the V.A.C.® over the skin graft during surgery to enhance graft incorporation. V.A.C.® therapy acts as a bolster, supports vascularization and graft incorporation proceeds very effectively.
In the case of an infected wound, we rely on appropriate antibiotics, but we also may apply the V.A.C.® system. Here it works as an adjunct to I.V. antibiotics in the treatment of an infected wound.
Pressure ulcers are very responsive to V.A.C.® therapy. A patient with a pressure ulcer will be evaluated for appropriateness, and if deemed to be so, the V.A.C.® is applied.
V.A.C.® therapy needs to be placed on viable tissue. It will not revitalize dead tissues. Therefore, any wound that is being considered for V.A.C.® therapy must be derided prior to placement. Also, a wound must have adequate systemic nutrition in order to heal. The V.A.C.® is not magic. The body must have the adequate building blocks for healing.
Wounds1: How widespread is the use of V.A.C.® therapy?
Eastman: When I started using V.A.C.® therapy four to five years ago, it was brand-new to everyone. Today, the V.A.C.® therapy option is common knowledge thanks to continued scientific research, professional discussion and media publicity. Wound specialists are very informed about V.A.C.® therapy and healthcare specialists throughout the continuum are also becoming more familiar with the science behind this therapy.
V.A.C.® therapy was initially a revolution in the care of chronic wounds. It is now being recommended in areas of acute wound therapy such as burns and abdominal compartment syndrome. A burn draws fluids from around the wound. Actually increasing the tissue destruction over time. A second-degree burn can convert to a third- or fourth-degree over 24 hours as the zone of stasis prevents blood from reaching the initial injury. If you apply controlled negative pressure on a second-degree burn, optimally within the first 6 hours following injury, it helps alleviate the stasis and reduces the potential for further tissue damage.
Abdominal compartment syndrome results from raised intra-abdominal pressure. Various clinical conditions associated with this condition include massive intra-abdominal hemorrhage, edema, and intestinal obstruction. The mortality rate associated with abdominal compartment syndrome is very high. Negative pressure wound therapy has been used as a helpful adjunctive therapy for select patients with this condition. Although V.A.C.® therapy is not yet widely used in abdominal compartment syndrome, it has proven to be effective in managing the open abdomen and assisting in reduction of intra-abdominal pressures. If V.A.C.® therapy saves even a percentage of those people, it's a success.
I have an extensive picture portfolio of wounds that our multidisciplinary team has treated over the years, illustrations of cases where people would have almost certainly died without V.A.C.® therapy. One terrible example is where a patient developed necrotizing fasciitis, better known by the media as the “flesh eating disease”.
When diagnosed with this often deadly condition, the only treatment course is massive surgical debridement (cleaning out) and extensive antibiotic therapy. Surgical intervention requires the removal of all affected tissue including a safety margin of clean tissue. This leaves the patient with truly massive wounds, which carry with them life-threatening complications – fluid balance problems, susceptibility to further infection, or muscle breakdown; all of which have serious systemic implications. Many times these patients, even with proper surgical debriedment and medical management have died just from the sheer loss of body mass.
That's changing thanks to negative pressure wound therapy technology. A patient that we treated with V.A.C.® therapy following surgical debriedment for necrotizing fasciitis, in which he lost approximately three-quarters of the tissue on one of his legs, is now back to work. The V.A.C.® was one aspect in the overall plan of care, but it is unlikely that the patient would have saved his leg without this therapy. After eight months of rehabilitation, he is back at work with a functional leg, if not a beautiful leg, but he is walking on it!