Skin & Aging’s sister journal Wounds is the nation’s leading wound care research journal, and it’s the major source of current research, treatment methodology, and protocol in the field of wound care. In addition, this journal is the standard reference tool for those healthcare professionals who are leaders in establishing wound care programs and treatment centers both nationally and internationally.
This month, we bring you the top 10 selections from the whole body of research published in Wounds in 2007.
Dermatologist and wound care expert, Dr. Robert Kirsner, who is Section Editor for Wounds and an Editorial Advisory Board Member for Skin & Aging, selected the following research findings as the most relevant to dermatology. Read on for Dr. Kirsner’s commentary on the relevance of this research as well as a synopses of these wound care findings.
1 The Year of the Pressure Ulcer: Understanding Who’s At Risk
Dr. Kirsner’s Comments:
This year may be the year of the pressure ulcer. The reason for this is that the federal government has mandated that hospital-acquired pressure ulcers not be reimbursed by CMS starting in October 2008.
Of all chronic wounds, pressure ulcers are the most common and the most costly to the Medicare system. This is significant and is one of 9 “quality measures” that the government wishes to implement this year.
Others of importance to dermatologists may include surgical site infections. This is significant because one out of every five Medicare-age hospitalized patients will develop a pressure ulcer during their hospital stay. Therefore, it is paramount to identify the patients at greatest risk and institute risk prevention strategies to obviate the development of these costly pressure ulcers. Often, at-risk patients are thought to have significant cognitive impairment. However, even mentally intact patients are at risk as demonstrated by Magalhães et al.
Risk factors such as humidity, activity, mobility, friction and shear can be assessed accurately by prediction scales such as the Braden scale. These factors are known to be important in pressure ulcer development. Monitoring for these factors and then implementing preventive strategies can lessen ulcer development and the financial impact of impending regulations.
Synopsis of the Research:
Pressure ulcers are blamed for the deaths of an estimated 60,000 patients a year in the United States. Clinicians do not fully understand which people are most likely to develop the condition, but Brazilian researchers have shed some light on the problem.
Marta G. Magalhães, M.D., and her colleagues at the Hospital das Clinicas Samuel Libanio, in Pouso Alegre, looked for the risk factors for pressure ulcers in 40 elderly, hospitalized patients (average age above 70 years) without evidence of significant cognitive impairment. Of those, 20 had been diagnosed with at least one ulcer, most of which were classified as Stage II or Stage I.
The most frequent co-morbidities in ulcer patients were hypertension, diabetes, dyslipidemia and heart failure, the researchers said. Reasons for hospitalization included hip fracture, heart failure, pneumonia, trauma, airway disease and other ailments.
Ulcer patients spent about 10 days longer in the hospital, on average, than patients without the lesions (23.2±18.8 vs. 13±10.4 days), the researchers found. However, this difference in hospital stays did not reach statistical significance.
Patients who developed ulcers had significantly lower scores on the Braden Scale — which takes account of the intensity and duration of pressure, as well as tissue tolerance — than did those who did not develop the lesions, according to the researchers. The investigators set Braden score of 18 as a threshold so that 90% of patients at risk for a pressure ulcer would be included in the analysis.
The researchers found that moisture, activity, mobility and shear force and friction were statistically significant risk factors for development of a pressure ulcer (P<0.05).
Intriguingly, although sex has not been previously identified as a risk factor for pressure ulcers, Dr. Magalhães’s group found that 14 (70%) of the patients who developed ulcers were women.
“Data from the present study illustrate that older patients without significant cognitive impairment have increased risk factors for developing pressure ulcers,” concluded the researchers.
SOURCE: Marta G. Magalhães, M.D.; Alfredo Gragnani, M.D., Ph.D.; Daniela F. Veiga, M.D., et al. Risk Factors for Pressure Ulcers in Hospitalized Elderly without Significant Cognitive Impairment. Wounds. January 2007;19:20-24.
2 The Year of the Pressure Ulcer: Reducing Risk
Dr. Kirsner’s Comments:
Offloading is the standard of care for patients with pressure ulcers and for diabetic neuropathic foot ulcers. The emerging importance of pressure ulcers in the hospital setting and its rapid and quick treatment are imperative. Therefore, understanding when a person is at risk because of increased pressure is important.
Scales developed to predict risk, such as the Braden ad Norton scales, are helpful, but direct measurement of pressure to help design a critical off loading plan is needed.
Pressure sensing devices have been developed experimentally to try to assist clinicians in treating patients with pressure. Their utility in clinical practice is limited, but the need exists for an everyday, easy-to-use, inexpensive device to monitor pressure. Ideally, this pressure sensing device might provide alerts or alarms as well and have collectable data to download and analyze to provide a basis for continuous quality improvement.
Synopsis of the Research:
Pressure ulcers are a major source of morbidity for diabetics and bedridden patients. The lesions result from mechanical stress on and lack of blood flow to skin that has become compressed between the skeleton and a hard surface such as a wheelchair cushion, shoe inner or a mattress.
Recent advances in pressure-sensing technology are enabling clinicians to better prevent pressure ulcers. These devices, which include sensors that can be placed inside shoes and total contact casts to measure foot offloading, or placed under the buttocks to measure sitting pressure, can give doctors a detailed picture of where particular patients are at highest risk of developing an ulcer.
As Amit Gefen, Ph.D., a biomedical engineer at Tel Aviv University in Israel describes in a recent review article in Wounds, “visualization of pressure data is commonly done by means of color-coded diagrams, which show the area of contact (under the foot or buttocks) with regions of high pressure marked using ‘warm’ colors (red or yellow), and regions of low pressure marked using ‘cold’ colors (blue or green).”
However, Dr. Gefen adds, the data also can be presented as isobars and, less commonly, three-dimensional topographical maps. Commercially available software can perform pressure analysis, calculating contact area, compression force peak pressure and other parameters. All these data can be collected in real time at the point of care.
As Dr. Gefen explained, pressure measurements help clinicians and patients in two ways. The technology can provide feedback to patients with nerve damage, from diabetic neuropathy, for example, that has deadened sensation in a body part. It can also help evaluate the suitability of a wheelchair cushion or other padding in order to provide a patient the most comfortable fit —and one less likely to cause a pressure ulcer.
“Body-support pressure measurement systems should be considered a practical tool for protecting insensitive patients from diabetic foot ulcers and sitting-acquired pressure ulcers,” Dr. Gefen wrote. “The computerized pressure-sensing devices currently available on the market … provide real-time quantitative and objective feedback to the clinicians, which allows on-the-spot decision-making during patient evaluation.
SOURCE: Gefen, Amit, Ph.D. Pressure-Sensing Devices for Assessment of Soft Tissue Loading Under Bony Prominences: Technological Concepts and Clinical Utilization. Wounds. December 2007;19:350-362.
3 Improving Diagnostic Accuracy of Swab Cultures
Dr. Kirsner’s Comments:
The diagnosis of infection is currently based on clinical evaluation of a wound. Certainly, wounds of that are surrounded by an advancing erythematous border associated with pain, tenderness and warmth are suggestive of a wound infection. However, other situations exist in which bacteria within the wound may be of importance. For example, in the absence of infection critical colonization may impede healing.
In this situation, bacteria could be in numbers large enough to prevent a wound from healing but not be tissue invasive or cause a host response. These patients may experience failure to heal and the only signs might be increased drainage.
Better diagnostic tests are needed to diagnose infection in those cases and to direct antibiotic therapy. Targeted antibiotic therapy relies on culture results. Therefore, the technique of culturing is important.
Gardner and colleagues reported that technique of culturing called the Levine technique can produce superior culture results. Levine’s techniques involves collecting swab cultures by rotating a swab over a 1 cm2 area of the wound with sufficient pressure to extract fluid from the wound.
This technique is superior to other culture techniques and is currently the preferred culture technique. Of note, anesthesia with EMLA may have antibacterial properties and is not recommended prior to obtaining cultures.
Synopsis of the Research:
Semiquantitative swab cultures provide less accurate information about both the presence and type of bacteria in wounds than do quantitative methods, a recent study found. However, the researchers say, even the more sophisticated sampling must be performed properly to assure good test results.
Sue E. Gardner, R.N., Ph.D., of the University of Iowa College of Nursing, and her colleagues sought to compare semiquantitative culturing with quantitative culturing in 44 chronic wounds. Swab cultures were conducted with Levine’s technique.
Using receiver operating characteristic curve analysis, the researchers found that semiquantitative swab cultures had an area under the curve (AUC) of about 0.64 — not much higher than the 0.5 figure reflective of chance (P=0.0501). The AUC for quantitative cultures, however, was 0.821 (P=0.0128).
Similarly, semiquantitative cultures showed less concordance with tissue cultures at recovering all organisms present in a wound than did quantitative cultures (57% vs. 72%).
The researchers acknowledged that semiquantitative cultures are simpler and less costly to analyze than quantitative samples. But, they added that the lack of precise information the semiquantitative tests provided calls into question how the results should be interpreted.
“Use of a semiquantitative swab culture is of less value in guiding wound care decisions than a quantitative swab culture because the semiquantitative swab provides less accurate information regarding the true bacterial burden of the wound tissue,” the researchers wrote. “However, care must be taken to collect swab specimens in a manner that insures the acquisition of microbes from within the wound tissue such as that provided with Levine’s technique.”
The authors noted that local anesthetic agents have been shown to affect the validity of swab cultures by killing bacteria. As a result, they recommended using preservative-free 1% lidocaine that had been applied no more than 2 hours prior to sampling.
SOURCE: Sue E. Gardner, R.N., Ph.D.; Rita Frantz, R.N., Ph.D.; Stephen L. Hillis, R.N., Ph.D., et al. Diagnostic Validity of Semiquantitative Swab Cultures. Wounds. February 2007;19:31-38.
4 Chronic Wounds: Which Heal, Which Don’t — Using Your Crystal Ball
Dr. Kirsner’s Comments:
Predicting which wound will heal and which won’t is important to ensure superior patient compliance as well as for offering more rapid and efficacious use of adjuvant therapy. Factors such as wound size and wound duration have been eloquently shown to be predictive of healing both diabetic foot and venous leg ulcers.
For example: A venous leg ulcer that is less than 6 months duration and smaller than 5 cm2 is likely (93%) to heal with standard of care (which is multilayered compression bandages). While a wound with large size (>5 cm2) and long duration (present >6 months) is unlikely to heal (13% with standard of care).
Understanding these factors helps stratify risk, enables better comparison of outcomes, and allows clinicians to use judicious adjunctive therapy in a more cost- effective manner.
Jones et al added to the literature by finding that insurance status and socioeconomic status (Medicaid insurance) and race (non-white) are also predictive of failure to heal. These patients are greater risk for having problematic wounds. Therefore, rapid intervention is critical to improve outcomes in this subset of patients
Synopsis of the Research:
Many factors, from the quality of treatment to patients’ race and the source of their health insurance, appear to influence the likelihood that their chronic wounds will heal swiftly.
A retrospective study looked for predictors of fast- and slow-healing wounds in 400 men and women with three kinds of chronic lesions:
1. pressure
2. diabetic
3. venous ulcers.
These lesions were treated at four different institutions ranging from a teaching hospital to a wound care clinic.
Of the total, 51 (12%) experienced healing within 3 weeks of starting treatment. Among the 347 patients with “nonhealing” ulcers, 195 (56%) wounds did not resolve within the 6-month study period.
Dr. Jones’s group confirmed several well-known risk factors for poorly healing wounds, including larger, deeper lesions and ulcers with significant exudates, yellow slough and black eschar. Patients whose wounds showed multiple signs of infection within the first 3 months also experienced protracted healing, as did those who repeatedly received antibiotics during the study.
Interestingly, the investigators said, wounds treated more frequently with antimicrobial dressings also appeared to be less likely to heal rapidly, as did lesions that were mechanically debrided. Finally, racial minorities and patients with Medicaid were more likely to be non-healers than whites and those with other forms of insurance.
Factors linked to rapid healing included treatment with commercial cleaning products, being obese (as opposed to being malnourished) and having smaller, shallower wounds, having more than one ulcer and having ulcers linked to peripheral vascular disease or deep vein thrombosis.
Although some risk factors for stubborn ulcers are beyond the control of clinicians, the researchers say the results suggest that healthcare providers can do a better job of managing chronic wounds.
“Earlier identification and referral for treatment might lead to improved healing rates for some patients,” they wrote. “Remaining factors require the attention of those delivering wound care services. These include more carefully matching wound characteristics to selected dressings, and eliminating the use of mechanical debridement and cytotoxic agents.
These results also demonstrate the need for more complete documentation of wound characteristics for selection of appropriate interventions and for better monitoring of healing progression.”
SOURCE: Katherine R. Jones, R.N., Ph.D., FAAN; Kristopher Fennie, Ph.D., M.P.H.; Amber Leniha. Chronic Wounds: Factors Influencing Healing Within 3 Months and Nonhealing After 5–6 Months of Care. Wounds. March 2007;19:551-561.
5 The Blockbuster: Insights into Mechanisms
Dr. Kirsner’s Comments:
Negative pressure wound therapy (NPWT), a.k.a. vacuum-assisted closure (VAC) is a commonly employed adjuvant to heal large and deep wounds. A blockbuster device, NPWT has annual sales of more than $1 billion. The NPWT employs 125 mmHg negative pressure to a wound and has been shown in large series and more recently in randomized controlled trials to speed the healing of various wound types.
Clinically appealing because of the collection of large amounts of drainage, the mechanism by which the vacuum works, is more hypothesized than truly known. Among the factors thought to be important to its benefit include the physiologic stretching of cells, which renders them more productive, the collection of exudate that in many situations may have a negative effect on healing, and the stimulation of angiogenesis.
Norbury et al contributed to our knowledge of the mechanisms by which NPWT works by studying porcine full-thickness wounds. They found that NPWT reduced the number of peripheral monocytes and neutrophils with accompanying reduction in inflammatory cytokines such as IL-8, tumor necrosis factor alpha and transforming growth factor beta.
This information fits very well into one of the paradigms of why chronic wounds develop. n addition to cellular senescence, bacterial burden and deficient and/or unavailable growth factors, inflammation and the subsequent development of a proteolytic environment in the wound are thought causal in maintaining a chronic wound state. Reducing inflammatory cytokines would therefore be helpful in altering this abnormality.
Synopsis of the Research:
Porcine wounds treated with vacuum-assisted closure (VAC) therapy show less evidence of local and systemic inflammation than those treated with a moist dressing alone, a recent study suggested.
The study, by researchers at Kinetic Concepts, Inc., makers of the VAC device (also called negative pressure wound therapy), looked at the technology’s effect on inflammatory markers in 10 pigs given 2 “full-thickness” excisional wounds 5 cm in diameter. Six of the animals were treated with vacuum therapy and four received moist dressings without negative pressure.
Wounds treated with VAC appeared to heal faster than those in the control animals, the researchers noted. Blood tests of the treated pigs 36 hours after wounding revealed significantly lower amounts of monocytes (0.2 vs. 0.9 per nl; P<05). At 84 hours after wounding, treated animals also had fewer circulating neutrophils (5.4 vs. 13.6 per nl; P<0.05) than controls.
Statistically significant differences were seen in serum levels of INF-g and interleukin-6 (IL-6), although no differences were observed for other interleukins or in levels of tumor growth factor-b(TGF-b) or tumor necrosis factor-a.
Tests of fluid from the wounds themselves showed statistically significant reductions in IL-8 in the vacuum-treated lesions but only at the 12-hour mark, the researchers say. Concentrations of TGF-b also were lower in the fluid of VAC-treated wounds than in the control wounds (P<0.05) at the 132- and 180-hour mark.
“The results of this study support the hypothesis that [VAC Therapy] attenuates the early inflammatory response in a porcine acute wound healing model,” the researchers wrote. “Collectively, these responses corresponded to increased wound closure.”
SOURCE: Kenneth Norbury, B.S., Ph.D., and Kris Kieswetter, B.S., Ph.D., M.B.A. Vacuum-assisted Closure Therapy Attenuates the Inflammatory Response in a Porcine Acute Wound Healing Model. Wounds. April 2007;19:97-106.
6 Hope for Large Venous Ulcers
Dr. Kirsner’s Comments:
Skin grafting has been employed for centuries to cover non-healing wounds. Used in dermatology, primarily to improve the cosmetic outcome of full-thickness wounds, split-thickness skin grafts (STSG) have the benefit of more rapid take because of their relatively thin nature. However, they are generally employed for refractory or non-healing chronic wounds and controlled trials of autologous STSG have been not forthcoming. Additionally, the use of engineered skin which has the benefit of an off- the-shelf capability has in many cases precluded the use of autologous STSG that require the creation of the second wound with associated morbidity. Yet, the utility of split skin graft cannot be denied; this type of graft is still routinely practiced, so understanding the outcomes of its use is critical.
Jankunas et al now provide some objective data regarding the utility of STSG in treating venous leg ulcers. Although not a randomized study, they prospectively evaluated more than 70 patients with extremely large (50 cm2) venous ulcers. Two-thirds of the wounds healed after STSG and others improved compared with no complete healing in the control group that didn’t undergo grafting.
This report serves to reinforce our clinical perception of the benefits of STSG. Without doubt, in large ulcers of long duration, STSG should be considered as an option.
Synopsis of the Research:
Skin grafts are superior to non-surgical care for treating chronic venous leg ulcers, according to a recent study by Lithuanian researchers. The study found that patients with large ulcers who underwent grafts were more likely to experience complete epithelialization, a reduction in lesion size and to have the wounds remain closed 6 months after treatment.
Chronic venous leg ulcers (CVLUs), which generally result from venous insufficiency, are a significant source of morbidity in Lithuania, where nearly 2% of the population suffers from the condition, and elsewhere. They occur about twice as frequently among people over age 65 years.
In the latest study, Vytautas Jankunas, Ph.D., M.D., from Klaipeda County Hospital and his colleagues compared the effectiveness of partial-thickness skin autografting (ADP) with conservative care — hydrocolloid bandages and compression therapy — in 71 patients with CVLUs that had not resolved with other therapy.
None of the 31 patients who received conservative care saw their ulcers heal completely, the researchers reported. Average ulcer size in this group fell in 14 patients but rose in 17, while wound size shrank to 171 cm2 from 182 cm2 over the 6-month study period (P>0.5).
Of the 40 patients who underwent ADP followed by compression therapy, however, 27 (67%) had complete epithelialization of their ulcers, with the average wound area falling to 16 cm2 from 279 cm2 within 2 to 3 weeks after treatment. “In comparison with the previous area, the current area was rather small and did not (or was insignificant) influence patient quality of life,” the researchers wrote.
The researchers also looked at the bacteria present in the CLVUs, finding that Staphylococcus aureus and Pseudomonas aeruginosa were the most common organisms.
“Although the patients were taking medications to improve microcirculation, venous flow, and lymph drainage, the authors believe that the compressive therapy was responsible for the 6-month period where there were no cases of new ulcers opening in the group of operated patients,” they wrote.
SOURCE: Vytautas Jankunas, Ph.D., M.D.; Rokas Bagdonas, Ph.D., M.D.; Donatas Samsanavicius, M.D.; Rytis Rimdeika, Ph.D., M.D. An Analysis of the Effectiveness of Skin Grafting to Treat Chronic Venous Leg Ulcers. Wounds. May 2007;19:128-137.
7 More Arrows in your Quiver: PHMB, (Polyhexamethylene Biguanide)
Dr. Kirsner’s Comments:
The presence of bacteria in non-healing wounds and their potential effect on inhibiting healing has led to clinical agents used to address altering wound bacteria. A number of agents are currently available to treat bacteria within wounds including various silver dressings and cadexomer iodine preparations.
A relative newcomer to the antimicrobial scene has been polyhexamethylene biguanide (PHMB). This is a commonly employed household antiseptic used in various cleansers including pool cleansers as well as contact lens solution. It is therefore safe and well tolerated and thought to have little, if any, toxicity.
More recently, several dressings are currently available on the market that incorporate PHMB in the dressing material with labeled indication to prevent bacterial invasion from the outside into the wound. In practice and in animal studies, PHMB also reduced wound bacteria as well. Possessing a broad spectrum of antimicrobial action and little toxicity, PHMB is another option in combating excessive bacteria for wounds either critically colonized or infected.
Synopsis of the Research:
Wound dressings containing the antimicrobial agent PHMB promote cost-effective healing, according to a recent study which suggests that although the dressings are initially more expensive than conventional wet-to-dry gauze, they may pay for themselves over time.
The randomized, controlled study by Gerit Mulder, D.M.P., M.S., at the University of California, San Diego, comprised 12 patients with wounds of various causes, including venous statis, trauma, diabetes and other conditions. Results from four patients were used for a cost-effectiveness analysis.
Treatment with biosynthesized cellulose wound dressings (XCell) containing 0.3% PHMB led to an average decrease in wound size of 42% (to 4.57 cm2 from 6.79 cm2). Two, relatively small wounds healed completely during the study while two others expanded slightly, the researchers say. The average duration of use of PHMB was 25 days (range 5 to 52 days).
Although the antimicrobial dressings were initially more expensive than wet-to-dry gauze, they were more cost-effective when considering the time to achieve debridement of 50% or better. “The average cost of material was calculated to be $5.99 to $9.01 per day with the wounds demonstrating improvement or healing,” they write. The researchers did not include other costs of treatment, such as those involving clinic visits and staff time.
“The limited amount of information on the ability of antimicrobial dressings to significantly affect the healing process and wound closure supports the need for well designed and adequately powered clinical trials to determine the true role of these devices in the treatment of chronic wounds,” the authors concluded. “Current information and publications indicate a potential benefit regarding the use of these products in wound where bacterial burden may be delaying or impeding wound closure.”
SOURCE: Gerit D. Mulder, D.P.M., M.S.; Joseph P. Cavorsi, M.D.; Daniel K. Lee, D.P.M. An Analysis of the Effectiveness of Skin Grafting to Treat Chronic Venous Leg Ulcers. Wounds. July 2007;19:173-182.
8 Honey Sweet Death to Microbes
Dr. Kirsner’s Comments:
A spoonful of sugar may be the medicine. English researchers have confirmed that medicinal honey has significant antibacterial prowess against several strains of virulent pathogens, including those resistant to multiple antibiotics. Used for centuries, honey has been purported to speed healing of various wound types. Honey is thought to work because of its occlusive nature and its osmotic properties.
For many, honey has been thought by some to present an inexpensive alternative in developing countries to more occlusive expensive dressings. Not all honeys are equivalent. A specific brand of honey, the so-called Manuka honey predominantly sourced from Leptospermum species from New Zealand and Australia has been found to have other properties that may render it superior to other honeys. Specifically, this Manuka honey appears to have superior and broad- spectrum antimicrobial properties. To the average person, this may be seen as the lesser need for preservatives within honey. However, to patients with wounds, this antimicrobial action may have a beneficial effect on wound healing.
The first honey bandage to hit the market in the United States is called Medihoney. The public’s interest in and desire for natural products will likely draw significant interest in this product. The low-tech nature may not be as attractive to physicians and the hope is that well-done studies like those published by George and Cutting will help clarify a sticky subject.
Synopsis of the Research:
The researchers tested one form of medicinal honey, Medihoney (Medihoney Pty LTD), which is made in Australia from the Manuka plant, a member of the Leptospermum family.
Honey is believed to kill bacteria in at least four ways, according to the researchers.
1. Its high sugar content and low water activity promotes osmotic action
2. its acidic pH (3.2-4.5) blocks the growth of germs
3. it contains the enzyme glucose oxidase that stimulates the production of hydrogen peroxide; and
4. it may have plant-derived molecules, yet unidentified, that attack microorganisms.
The researchers exposed 130 bacteria isolates, including multidrug resistant Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, to various concentrations of Medihoney. They identified the minimum inhibitory concentrations (MIC) of the product for each strain to determine its antibiotic efficacy.
The effective concentration of Medihoney ranged from 4% to achieve a MIC of 90% for many bugs, such as methicillin-resistant and methicillin-susceptible S. aureus, to 14% for a MIC of 90% for extended-spectrum b-lactamase-positive P. aeruginosa.
Although the latest work was in vitro, the researchers note that a previous study by Johnson, et al (J Am Soc Nephrol. 2005;16:1456-1462) found that Medihoney was as effective as mupirocin at preventing catheter-associated infections.
“Given that mupirocin can reduce infection rates by at least 7 to 13 fold,” they wrote, “the prospect that Medihoney will prove to be an effective prophylactic is extremely helpful.”
SOURCE: Narelle May George; Keith F. Cutting. Antibacterial Honey(Medihoney): in-vitro Activity Against Clinical Isolates of MRSA, VRE, and Other Multiresistant Gram-negative Organisms Including Pseudomonas aeruginosa. Wounds. September 2007;19:231-236.
* Mr. Cutting disclosed that he has received research funding from Medihoney Pty.
9 Patient: Don’t Heal Thyself
Dr. Kirsner’s Comments:
The standard of care of venous leg ulcers is a use of multilayer compression bandages. Without compression bandages the likelihood of healing drops dramatically for patients with venous ulcers. These dressings are typically applied anywhere from twice weekly to every other week by skilled professionals. Unfortunately, this requires the patient to either have a home health nurse to visit him or to make visits to the office to have the bandages changed.
Conceptually, self-bandaging would be an alternative to this. However, the skills of applying a multilayer compression bandage are numerous, and potential adverse outcomes may result. It appears from the work of Fife and colleagues that asking patients to apply their own dressings in unrealistic. Studying a group of more than 500 patients, they found more than 50% needed assistance with routine activities of daily living. It is hard to imagine that this population of patients could manage dressing applications. This is critical information for physicians who might ask patients to apply their own bandages and payers who do not pay for alternative methods for dressing applications.
Synopsis of the Research:
More than half of patients with venous stasis ulcers reported having trouble going to the bathroom, bathing, walking and performing other routine activities — difficulty that may translate into their inability to properly dress their wounds.
The results come from a database analysis of more than 7,250 wound patients at 29 treatment centers. Of those patients, 547 were identified as having venous stasis ulcers.
Led by Caroline Fife, M.D., of the University of Texas Health Science Center in Houston, the researchers found that 55% of the patients required some help with activities of daily living, chiefly using the toilet and getting dressed.
“If a patient cannot dress him or herself or has a problem toileting, it is likely that the person will have problems applying a compression bandage, presuming that he or she has the knowledge to do so, which is a separate issue,” the researchers wrote. “Thus, more than half of these patients are unlikely to be able to participate in the necessary therapy to treat their venous stasis ulcers unless the help of family members or healthcare professionals is available.”
The authors noted that the cost to the U.S. healthcare system of treating venous stasis ulcers is estimated to range from $2.5 billion to $3.5 billion per year.
“If patients cannot afford the costs of basic compression bandaging and cannot self-bandage, costs to the healthcare system and patients alike will ultimately rise as ulcers become far less likely to heal,” the authors concluded.
SOURCE: Caroline Fife, M.D., B.S.; David Walker, C.H.T.; Brett Thomson, B.S.; Marissa Carter, Ph.D., M.A. Limitations of Daily Living Activities in Patients With Venous Stasis Ulcers Undergoing Compression Bandaging: Problems With the Concept of Self-bandaging. Wounds. October 2007;19:255-257.
10 More than the Eye Can See
Dr. Kirsner’s Comments:
Dermatology is the most visual of specialties, yet this aspect of dermatology is both a blessing and a curse. It allows the novice to assume expertise but also provides an easier maker for disease activity and progression.
Wound healing is similar. The clinical outcome for most wound healing studies is complete healing, as determined by visual inspection. However, both injury and repair occur at a microscopic and genomic level. Additionally, many products are aimed at improving the healing process and may not result in complete healing. For example, products aimed at improving the wound bed may reduce infection and therefore may not result in complete healing.
Measuring various outcomes may be important. Additionally, using surrogate endpoints for healing may aid in preliminary data collection and reduce the initial costs of emerging therapies. Marco Romanelii and colleagues examine objective methods to measure healing. These will be increasingly important in both research endeavors and clinical activities.
Synopsis of the Research:
The question of how well a wound is healing boils down to whether it is shrinking in size, with proper tissue recovery and no signs of infection. Increasingly, wound specialists are turning to technology to help find answers.
From venous leg ulcers to pressure lesions, standardized, objective methods of assessing wound healing are emerging. As a group of Italian wound specialists describe in a recent review article on the subject, technologies such as dedicated wound photography, laser Doppler perfusion imaging, transcutaneous oximetry and others can provide clinically important information about the health of injured tissue.
However, other key assessment tools require only a ruler and a sharpened pencil. Recording the product of a wound’s length by width to determine its area — and whether that number is getting smaller with treatment — has been shown to be a useful gauge of healing for venous leg ulcers, according to the article. “Of all the healing rate parameters assessed, early percent reduction in wound area has been the most reliable in predicting complete venous ulcer healing.”
A similar rule of thumb applies to patients with pressure ulcers, for whom percent reduction in pressure area is a strong predictor of healing prognosis during the first 2 weeks of treatment, and for patients with diabetic foot ulcers, the researchers write.
Optimal wound assessment hinges on the development of a “uniform, standardized, and well-established” combination of noninvasive measurements, the researchers wrote. “The objective assessment of chronic wounds during tissue repair will become a specific aspect within wound management, which will not replace the clinical assessment of expert caregivers, but may bring numerous advantages in terms of understanding and awareness of each wound management challenge,”
SOURCE: Marco Romanelli, M.D., Ph.D.; Valentina Dini, M.D.; Maria Stefania Bertone, N.T.; Cinzia Brilli, R.N. Outcomes Research — Measuring Wound Outcomes. Wounds. November 2007;19:294-298.
Skin & Aging’s sister journal Wounds is the nation’s leading wound care research journal, and it’s the major source of current research, treatment methodology, and protocol in the field of wound care. In addition, this journal is the standard reference tool for those healthcare professionals who are leaders in establishing wound care programs and treatment centers both nationally and internationally.
This month, we bring you the top 10 selections from the whole body of research published in Wounds in 2007.
Dermatologist and wound care expert, Dr. Robert Kirsner, who is Section Editor for Wounds and an Editorial Advisory Board Member for Skin & Aging, selected the following research findings as the most relevant to dermatology. Read on for Dr. Kirsner’s commentary on the relevance of this research as well as a synopses of these wound care findings.
1 The Year of the Pressure Ulcer: Understanding Who’s At Risk
Dr. Kirsner’s Comments:
This year may be the year of the pressure ulcer. The reason for this is that the federal government has mandated that hospital-acquired pressure ulcers not be reimbursed by CMS starting in October 2008.
Of all chronic wounds, pressure ulcers are the most common and the most costly to the Medicare system. This is significant and is one of 9 “quality measures” that the government wishes to implement this year.
Others of importance to dermatologists may include surgical site infections. This is significant because one out of every five Medicare-age hospitalized patients will develop a pressure ulcer during their hospital stay. Therefore, it is paramount to identify the patients at greatest risk and institute risk prevention strategies to obviate the development of these costly pressure ulcers. Often, at-risk patients are thought to have significant cognitive impairment. However, even mentally intact patients are at risk as demonstrated by Magalhães et al.
Risk factors such as humidity, activity, mobility, friction and shear can be assessed accurately by prediction scales such as the Braden scale. These factors are known to be important in pressure ulcer development. Monitoring for these factors and then implementing preventive strategies can lessen ulcer development and the financial impact of impending regulations.
Synopsis of the Research:
Pressure ulcers are blamed for the deaths of an estimated 60,000 patients a year in the United States. Clinicians do not fully understand which people are most likely to develop the condition, but Brazilian researchers have shed some light on the problem.
Marta G. Magalhães, M.D., and her colleagues at the Hospital das Clinicas Samuel Libanio, in Pouso Alegre, looked for the risk factors for pressure ulcers in 40 elderly, hospitalized patients (average age above 70 years) without evidence of significant cognitive impairment. Of those, 20 had been diagnosed with at least one ulcer, most of which were classified as Stage II or Stage I.
The most frequent co-morbidities in ulcer patients were hypertension, diabetes, dyslipidemia and heart failure, the researchers said. Reasons for hospitalization included hip fracture, heart failure, pneumonia, trauma, airway disease and other ailments.
Ulcer patients spent about 10 days longer in the hospital, on average, than patients without the lesions (23.2±18.8 vs. 13±10.4 days), the researchers found. However, this difference in hospital stays did not reach statistical significance.
Patients who developed ulcers had significantly lower scores on the Braden Scale — which takes account of the intensity and duration of pressure, as well as tissue tolerance — than did those who did not develop the lesions, according to the researchers. The investigators set Braden score of 18 as a threshold so that 90% of patients at risk for a pressure ulcer would be included in the analysis.
The researchers found that moisture, activity, mobility and shear force and friction were statistically significant risk factors for development of a pressure ulcer (P<0.05).
Intriguingly, although sex has not been previously identified as a risk factor for pressure ulcers, Dr. Magalhães’s group found that 14 (70%) of the patients who developed ulcers were women.
“Data from the present study illustrate that older patients without significant cognitive impairment have increased risk factors for developing pressure ulcers,” concluded the researchers.
SOURCE: Marta G. Magalhães, M.D.; Alfredo Gragnani, M.D., Ph.D.; Daniela F. Veiga, M.D., et al. Risk Factors for Pressure Ulcers in Hospitalized Elderly without Significant Cognitive Impairment. Wounds. January 2007;19:20-24.
2 The Year of the Pressure Ulcer: Reducing Risk
Dr. Kirsner’s Comments:
Offloading is the standard of care for patients with pressure ulcers and for diabetic neuropathic foot ulcers. The emerging importance of pressure ulcers in the hospital setting and its rapid and quick treatment are imperative. Therefore, understanding when a person is at risk because of increased pressure is important.
Scales developed to predict risk, such as the Braden ad Norton scales, are helpful, but direct measurement of pressure to help design a critical off loading plan is needed.
Pressure sensing devices have been developed experimentally to try to assist clinicians in treating patients with pressure. Their utility in clinical practice is limited, but the need exists for an everyday, easy-to-use, inexpensive device to monitor pressure. Ideally, this pressure sensing device might provide alerts or alarms as well and have collectable data to download and analyze to provide a basis for continuous quality improvement.
Synopsis of the Research:
Pressure ulcers are a major source of morbidity for diabetics and bedridden patients. The lesions result from mechanical stress on and lack of blood flow to skin that has become compressed between the skeleton and a hard surface such as a wheelchair cushion, shoe inner or a mattress.
Recent advances in pressure-sensing technology are enabling clinicians to better prevent pressure ulcers. These devices, which include sensors that can be placed inside shoes and total contact casts to measure foot offloading, or placed under the buttocks to measure sitting pressure, can give doctors a detailed picture of where particular patients are at highest risk of developing an ulcer.
As Amit Gefen, Ph.D., a biomedical engineer at Tel Aviv University in Israel describes in a recent review article in Wounds, “visualization of pressure data is commonly done by means of color-coded diagrams, which show the area of contact (under the foot or buttocks) with regions of high pressure marked using ‘warm’ colors (red or yellow), and regions of low pressure marked using ‘cold’ colors (blue or green).”
However, Dr. Gefen adds, the data also can be presented as isobars and, less commonly, three-dimensional topographical maps. Commercially available software can perform pressure analysis, calculating contact area, compression force peak pressure and other parameters. All these data can be collected in real time at the point of care.
As Dr. Gefen explained, pressure measurements help clinicians and patients in two ways. The technology can provide feedback to patients with nerve damage, from diabetic neuropathy, for example, that has deadened sensation in a body part. It can also help evaluate the suitability of a wheelchair cushion or other padding in order to provide a patient the most comfortable fit —and one less likely to cause a pressure ulcer.
“Body-support pressure measurement systems should be considered a practical tool for protecting insensitive patients from diabetic foot ulcers and sitting-acquired pressure ulcers,” Dr. Gefen wrote. “The computerized pressure-sensing devices currently available on the market … provide real-time quantitative and objective feedback to the clinicians, which allows on-the-spot decision-making during patient evaluation.
SOURCE: Gefen, Amit, Ph.D. Pressure-Sensing Devices for Assessment of Soft Tissue Loading Under Bony Prominences: Technological Concepts and Clinical Utilization. Wounds. December 2007;19:350-362.
3 Improving Diagnostic Accuracy of Swab Cultures
Dr. Kirsner’s Comments:
The diagnosis of infection is currently based on clinical evaluation of a wound. Certainly, wounds of that are surrounded by an advancing erythematous border associated with pain, tenderness and warmth are suggestive of a wound infection. However, other situations exist in which bacteria within the wound may be of importance. For example, in the absence of infection critical colonization may impede healing.
In this situation, bacteria could be in numbers large enough to prevent a wound from healing but not be tissue invasive or cause a host response. These patients may experience failure to heal and the only signs might be increased drainage.
Better diagnostic tests are needed to diagnose infection in those cases and to direct antibiotic therapy. Targeted antibiotic therapy relies on culture results. Therefore, the technique of culturing is important.
Gardner and colleagues reported that technique of culturing called the Levine technique can produce superior culture results. Levine’s techniques involves collecting swab cultures by rotating a swab over a 1 cm2 area of the wound with sufficient pressure to extract fluid from the wound.
This technique is superior to other culture techniques and is currently the preferred culture technique. Of note, anesthesia with EMLA may have antibacterial properties and is not recommended prior to obtaining cultures.
Synopsis of the Research:
Semiquantitative swab cultures provide less accurate information about both the presence and type of bacteria in wounds than do quantitative methods, a recent study found. However, the researchers say, even the more sophisticated sampling must be performed properly to assure good test results.
Sue E. Gardner, R.N., Ph.D., of the University of Iowa College of Nursing, and her colleagues sought to compare semiquantitative culturing with quantitative culturing in 44 chronic wounds. Swab cultures were conducted with Levine’s technique.
Using receiver operating characteristic curve analysis, the researchers found that semiquantitative swab cultures had an area under the curve (AUC) of about 0.64 — not much higher than the 0.5 figure reflective of chance (P=0.0501). The AUC for quantitative cultures, however, was 0.821 (P=0.0128).
Similarly, semiquantitative cultures showed less concordance with tissue cultures at recovering all organisms present in a wound than did quantitative cultures (57% vs. 72%).
The researchers acknowledged that semiquantitative cultures are simpler and less costly to analyze than quantitative samples. But, they added that the lack of precise information the semiquantitative tests provided calls into question how the results should be interpreted.
“Use of a semiquantitative swab culture is of less value in guiding wound care decisions than a quantitative swab culture because the semiquantitative swab provides less accurate information regarding the true bacterial burden of the wound tissue,” the researchers wrote. “However, care must be taken to collect swab specimens in a manner that insures the acquisition of microbes from within the wound tissue such as that provided with Levine’s technique.”
The authors noted that local anesthetic agents have been shown to affect the validity of swab cultures by killing bacteria. As a result, they recommended using preservative-free 1% lidocaine that had been applied no more than 2 hours prior to sampling.
SOURCE: Sue E. Gardner, R.N., Ph.D.; Rita Frantz, R.N., Ph.D.; Stephen L. Hillis, R.N., Ph.D., et al. Diagnostic Validity of Semiquantitative Swab Cultures. Wounds. February 2007;19:31-38.
4 Chronic Wounds: Which Heal, Which Don’t — Using Your Crystal Ball
Dr. Kirsner’s Comments:
Predicting which wound will heal and which won’t is important to ensure superior patient compliance as well as for offering more rapid and efficacious use of adjuvant therapy. Factors such as wound size and wound duration have been eloquently shown to be predictive of healing both diabetic foot and venous leg ulcers.
For example: A venous leg ulcer that is less than 6 months duration and smaller than 5 cm2 is likely (93%) to heal with standard of care (which is multilayered compression bandages). While a wound with large size (>5 cm2) and long duration (present >6 months) is unlikely to heal (13% with standard of care).
Understanding these factors helps stratify risk, enables better comparison of outcomes, and allows clinicians to use judicious adjunctive therapy in a more cost- effective manner.
Jones et al added to the literature by finding that insurance status and socioeconomic status (Medicaid insurance) and race (non-white) are also predictive of failure to heal. These patients are greater risk for having problematic wounds. Therefore, rapid intervention is critical to improve outcomes in this subset of patients
Synopsis of the Research:
Many factors, from the quality of treatment to patients’ race and the source of their health insurance, appear to influence the likelihood that their chronic wounds will heal swiftly.
A retrospective study looked for predictors of fast- and slow-healing wounds in 400 men and women with three kinds of chronic lesions:
1. pressure
2. diabetic
3. venous ulcers.
These lesions were treated at four different institutions ranging from a teaching hospital to a wound care clinic.
Of the total, 51 (12%) experienced healing within 3 weeks of starting treatment. Among the 347 patients with “nonhealing” ulcers, 195 (56%) wounds did not resolve within the 6-month study period.
Dr. Jones’s group confirmed several well-known risk factors for poorly healing wounds, including larger, deeper lesions and ulcers with significant exudates, yellow slough and black eschar. Patients whose wounds showed multiple signs of infection within the first 3 months also experienced protracted healing, as did those who repeatedly received antibiotics during the study.
Interestingly, the investigators said, wounds treated more frequently with antimicrobial dressings also appeared to be less likely to heal rapidly, as did lesions that were mechanically debrided. Finally, racial minorities and patients with Medicaid were more likely to be non-healers than whites and those with other forms of insurance.
Factors linked to rapid healing included treatment with commercial cleaning products, being obese (as opposed to being malnourished) and having smaller, shallower wounds, having more than one ulcer and having ulcers linked to peripheral vascular disease or deep vein thrombosis.
Although some risk factors for stubborn ulcers are beyond the control of clinicians, the researchers say the results suggest that healthcare providers can do a better job of managing chronic wounds.
“Earlier identification and referral for treatment might lead to improved healing rates for some patients,” they wrote. “Remaining factors require the attention of those delivering wound care services. These include more carefully matching wound characteristics to selected dressings, and eliminating the use of mechanical debridement and cytotoxic agents.
These results also demonstrate the need for more complete documentation of wound characteristics for selection of appropriate interventions and for better monitoring of healing progression.”
SOURCE: Katherine R. Jones, R.N., Ph.D., FAAN; Kristopher Fennie, Ph.D., M.P.H.; Amber Leniha. Chronic Wounds: Factors Influencing Healing Within 3 Months and Nonhealing After 5–6 Months of Care. Wounds. March 2007;19:551-561.
5 The Blockbuster: Insights into Mechanisms
Dr. Kirsner’s Comments:
Negative pressure wound therapy (NPWT), a.k.a. vacuum-assisted closure (VAC) is a commonly employed adjuvant to heal large and deep wounds. A blockbuster device, NPWT has annual sales of more than $1 billion. The NPWT employs 125 mmHg negative pressure to a wound and has been shown in large series and more recently in randomized controlled trials to speed the healing of various wound types.
Clinically appealing because of the collection of large amounts of drainage, the mechanism by which the vacuum works, is more hypothesized than truly known. Among the factors thought to be important to its benefit include the physiologic stretching of cells, which renders them more productive, the collection of exudate that in many situations may have a negative effect on healing, and the stimulation of angiogenesis.
Norbury et al contributed to our knowledge of the mechanisms by which NPWT works by studying porcine full-thickness wounds. They found that NPWT reduced the number of peripheral monocytes and neutrophils with accompanying reduction in inflammatory cytokines such as IL-8, tumor necrosis factor alpha and transforming growth factor beta.
This information fits very well into one of the paradigms of why chronic wounds develop. n addition to cellular senescence, bacterial burden and deficient and/or unavailable growth factors, inflammation and the subsequent development of a proteolytic environment in the wound are thought causal in maintaining a chronic wound state. Reducing inflammatory cytokines would therefore be helpful in altering this abnormality.
Synopsis of the Research:
Porcine wounds treated with vacuum-assisted closure (VAC) therapy show less evidence of local and systemic inflammation than those treated with a moist dressing alone, a recent study suggested.
The study, by researchers at Kinetic Concepts, Inc., makers of the VAC device (also called negative pressure wound therapy), looked at the technology’s effect on inflammatory markers in 10 pigs given 2 “full-thickness” excisional wounds 5 cm in diameter. Six of the animals were treated with vacuum therapy and four received moist dressings without negative pressure.
Wounds treated with VAC appeared to heal faster than those in the control animals, the researchers noted. Blood tests of the treated pigs 36 hours after wounding revealed significantly lower amounts of monocytes (0.2 vs. 0.9 per nl; P<05). At 84 hours after wounding, treated animals also had fewer circulating neutrophils (5.4 vs. 13.6 per nl; P<0.05) than controls.
Statistically significant differences were seen in serum levels of INF-g and interleukin-6 (IL-6), although no differences were observed for other interleukins or in levels of tumor growth factor-b(TGF-b) or tumor necrosis factor-a.
Tests of fluid from the wounds themselves showed statistically significant reductions in IL-8 in the vacuum-treated lesions but only at the 12-hour mark, the researchers say. Concentrations of TGF-b also were lower in the fluid of VAC-treated wounds than in the control wounds (P<0.05) at the 132- and 180-hour mark.
“The results of this study support the hypothesis that [VAC Therapy] attenuates the early inflammatory response in a porcine acute wound healing model,” the researchers wrote. “Collectively, these responses corresponded to increased wound closure.”
SOURCE: Kenneth Norbury, B.S., Ph.D., and Kris Kieswetter, B.S., Ph.D., M.B.A. Vacuum-assisted Closure Therapy Attenuates the Inflammatory Response in a Porcine Acute Wound Healing Model. Wounds. April 2007;19:97-106.
6 Hope for Large Venous Ulcers
Dr. Kirsner’s Comments:
Skin grafting has been employed for centuries to cover non-healing wounds. Used in dermatology, primarily to improve the cosmetic outcome of full-thickness wounds, split-thickness skin grafts (STSG) have the benefit of more rapid take because of their relatively thin nature. However, they are generally employed for refractory or non-healing chronic wounds and controlled trials of autologous STSG have been not forthcoming. Additionally, the use of engineered skin which has the benefit of an off- the-shelf capability has in many cases precluded the use of autologous STSG that require the creation of the second wound with associated morbidity. Yet, the utility of split skin graft cannot be denied; this type of graft is still routinely practiced, so understanding the outcomes of its use is critical.
Jankunas et al now provide some objective data regarding the utility of STSG in treating venous leg ulcers. Although not a randomized study, they prospectively evaluated more than 70 patients with extremely large (50 cm2) venous ulcers. Two-thirds of the wounds healed after STSG and others improved compared with no complete healing in the control group that didn’t undergo grafting.
This report serves to reinforce our clinical perception of the benefits of STSG. Without doubt, in large ulcers of long duration, STSG should be considered as an option.
Synopsis of the Research:
Skin grafts are superior to non-surgical care for treating chronic venous leg ulcers, according to a recent study by Lithuanian researchers. The study found that patients with large ulcers who underwent grafts were more likely to experience complete epithelialization, a reduction in lesion size and to have the wounds remain closed 6 months after treatment.
Chronic venous leg ulcers (CVLUs), which generally result from venous insufficiency, are a significant source of morbidity in Lithuania, where nearly 2% of the population suffers from the condition, and elsewhere. They occur about twice as frequently among people over age 65 years.
In the latest study, Vytautas Jankunas, Ph.D., M.D., from Klaipeda County Hospital and his colleagues compared the effectiveness of partial-thickness skin autografting (ADP) with conservative care — hydrocolloid bandages and compression therapy — in 71 patients with CVLUs that had not resolved with other therapy.
None of the 31 patients who received conservative care saw their ulcers heal completely, the researchers reported. Average ulcer size in this group fell in 14 patients but rose in 17, while wound size shrank to 171 cm2 from 182 cm2 over the 6-month study period (P>0.5).
Of the 40 patients who underwent ADP followed by compression therapy, however, 27 (67%) had complete epithelialization of their ulcers, with the average wound area falling to 16 cm2 from 279 cm2 within 2 to 3 weeks after treatment. “In comparison with the previous area, the current area was rather small and did not (or was insignificant) influence patient quality of life,” the researchers wrote.
The researchers also looked at the bacteria present in the CLVUs, finding that Staphylococcus aureus and Pseudomonas aeruginosa were the most common organisms.
“Although the patients were taking medications to improve microcirculation, venous flow, and lymph drainage, the authors believe that the compressive therapy was responsible for the 6-month period where there were no cases of new ulcers opening in the group of operated patients,” they wrote.
SOURCE: Vytautas Jankunas, Ph.D., M.D.; Rokas Bagdonas, Ph.D., M.D.; Donatas Samsanavicius, M.D.; Rytis Rimdeika, Ph.D., M.D. An Analysis of the Effectiveness of Skin Grafting to Treat Chronic Venous Leg Ulcers. Wounds. May 2007;19:128-137.
7 More Arrows in your Quiver: PHMB, (Polyhexamethylene Biguanide)
Dr. Kirsner’s Comments:
The presence of bacteria in non-healing wounds and their potential effect on inhibiting healing has led to clinical agents used to address altering wound bacteria. A number of agents are currently available to treat bacteria within wounds including various silver dressings and cadexomer iodine preparations.
A relative newcomer to the antimicrobial scene has been polyhexamethylene biguanide (PHMB). This is a commonly employed household antiseptic used in various cleansers including pool cleansers as well as contact lens solution. It is therefore safe and well tolerated and thought to have little, if any, toxicity.
More recently, several dressings are currently available on the market that incorporate PHMB in the dressing material with labeled indication to prevent bacterial invasion from the outside into the wound. In practice and in animal studies, PHMB also reduced wound bacteria as well. Possessing a broad spectrum of antimicrobial action and little toxicity, PHMB is another option in combating excessive bacteria for wounds either critically colonized or infected.
Synopsis of the Research:
Wound dressings containing the antimicrobial agent PHMB promote cost-effective healing, according to a recent study which suggests that although the dressings are initially more expensive than conventional wet-to-dry gauze, they may pay for themselves over time.
The randomized, controlled study by Gerit Mulder, D.M.P., M.S., at the University of California, San Diego, comprised 12 patients with wounds of various causes, including venous statis, trauma, diabetes and other conditions. Results from four patients were used for a cost-effectiveness analysis.
Treatment with biosynthesized cellulose wound dressings (XCell) containing 0.3% PHMB led to an average decrease in wound size of 42% (to 4.57 cm2 from 6.79 cm2). Two, relatively small wounds healed completely during the study while two others expanded slightly, the researchers say. The average duration of use of PHMB was 25 days (range 5 to 52 days).
Although the antimicrobial dressings were initially more expensive than wet-to-dry gauze, they were more cost-effective when considering the time to achieve debridement of 50% or better. “The average cost of material was calculated to be $5.99 to $9.01 per day with the wounds demonstrating improvement or healing,” they write. The researchers did not include other costs of treatment, such as those involving clinic visits and staff time.
“The limited amount of information on the ability of antimicrobial dressings to significantly affect the healing process and wound closure supports the need for well designed and adequately powered clinical trials to determine the true role of these devices in the treatment of chronic wounds,” the authors concluded. “Current information and publications indicate a potential benefit regarding the use of these products in wound where bacterial burden may be delaying or impeding wound closure.”
SOURCE: Gerit D. Mulder, D.P.M., M.S.; Joseph P. Cavorsi, M.D.; Daniel K. Lee, D.P.M. An Analysis of the Effectiveness of Skin Grafting to Treat Chronic Venous Leg Ulcers. Wounds. July 2007;19:173-182.
8 Honey Sweet Death to Microbes
Dr. Kirsner’s Comments:
A spoonful of sugar may be the medicine. English researchers have confirmed that medicinal honey has significant antibacterial prowess against several strains of virulent pathogens, including those resistant to multiple antibiotics. Used for centuries, honey has been purported to speed healing of various wound types. Honey is thought to work because of its occlusive nature and its osmotic properties.
For many, honey has been thought by some to present an inexpensive alternative in developing countries to more occlusive expensive dressings. Not all honeys are equivalent. A specific brand of honey, the so-called Manuka honey predominantly sourced from Leptospermum species from New Zealand and Australia has been found to have other properties that may render it superior to other honeys. Specifically, this Manuka honey appears to have superior and broad- spectrum antimicrobial properties. To the average person, this may be seen as the lesser need for preservatives within honey. However, to patients with wounds, this antimicrobial action may have a beneficial effect on wound healing.
The first honey bandage to hit the market in the United States is called Medihoney. The public’s interest in and desire for natural products will likely draw significant interest in this product. The low-tech nature may not be as attractive to physicians and the hope is that well-done studies like those published by George and Cutting will help clarify a sticky subject.
Synopsis of the Research:
The researchers tested one form of medicinal honey, Medihoney (Medihoney Pty LTD), which is made in Australia from the Manuka plant, a member of the Leptospermum family.
Honey is believed to kill bacteria in at least four ways, according to the researchers.
1. Its high sugar content and low water activity promotes osmotic action
2. its acidic pH (3.2-4.5) blocks the growth of germs
3. it contains the enzyme glucose oxidase that stimulates the production of hydrogen peroxide; and
4. it may have plant-derived molecules, yet unidentified, that attack microorganisms.
The researchers exposed 130 bacteria isolates, including multidrug resistant Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, to various concentrations of Medihoney. They identified the minimum inhibitory concentrations (MIC) of the product for each strain to determine its antibiotic efficacy.
The effective concentration of Medihoney ranged from 4% to achieve a MIC of 90% for many bugs, such as methicillin-resistant and methicillin-susceptible S. aureus, to 14% for a MIC of 90% for extended-spectrum b-lactamase-positive P. aeruginosa.
Although the latest work was in vitro, the researchers note that a previous study by Johnson, et al (J Am Soc Nephrol. 2005;16:1456-1462) found that Medihoney was as effective as mupirocin at preventing catheter-associated infections.
“Given that mupirocin can reduce infection rates by at least 7 to 13 fold,” they wrote, “the prospect that Medihoney will prove to be an effective prophylactic is extremely helpful.”
SOURCE: Narelle May George; Keith F. Cutting. Antibacterial Honey(Medihoney): in-vitro Activity Against Clinical Isolates of MRSA, VRE, and Other Multiresistant Gram-negative Organisms Including Pseudomonas aeruginosa. Wounds. September 2007;19:231-236.
* Mr. Cutting disclosed that he has received research funding from Medihoney Pty.
9 Patient: Don’t Heal Thyself
Dr. Kirsner’s Comments:
The standard of care of venous leg ulcers is a use of multilayer compression bandages. Without compression bandages the likelihood of healing drops dramatically for patients with venous ulcers. These dressings are typically applied anywhere from twice weekly to every other week by skilled professionals. Unfortunately, this requires the patient to either have a home health nurse to visit him or to make visits to the office to have the bandages changed.
Conceptually, self-bandaging would be an alternative to this. However, the skills of applying a multilayer compression bandage are numerous, and potential adverse outcomes may result. It appears from the work of Fife and colleagues that asking patients to apply their own dressings in unrealistic. Studying a group of more than 500 patients, they found more than 50% needed assistance with routine activities of daily living. It is hard to imagine that this population of patients could manage dressing applications. This is critical information for physicians who might ask patients to apply their own bandages and payers who do not pay for alternative methods for dressing applications.
Synopsis of the Research:
More than half of patients with venous stasis ulcers reported having trouble going to the bathroom, bathing, walking and performing other routine activities — difficulty that may translate into their inability to properly dress their wounds.
The results come from a database analysis of more than 7,250 wound patients at 29 treatment centers. Of those patients, 547 were identified as having venous stasis ulcers.
Led by Caroline Fife, M.D., of the University of Texas Health Science Center in Houston, the researchers found that 55% of the patients required some help with activities of daily living, chiefly using the toilet and getting dressed.
“If a patient cannot dress him or herself or has a problem toileting, it is likely that the person will have problems applying a compression bandage, presuming that he or she has the knowledge to do so, which is a separate issue,” the researchers wrote. “Thus, more than half of these patients are unlikely to be able to participate in the necessary therapy to treat their venous stasis ulcers unless the help of family members or healthcare professionals is available.”
The authors noted that the cost to the U.S. healthcare system of treating venous stasis ulcers is estimated to range from $2.5 billion to $3.5 billion per year.
“If patients cannot afford the costs of basic compression bandaging and cannot self-bandage, costs to the healthcare system and patients alike will ultimately rise as ulcers become far less likely to heal,” the authors concluded.
SOURCE: Caroline Fife, M.D., B.S.; David Walker, C.H.T.; Brett Thomson, B.S.; Marissa Carter, Ph.D., M.A. Limitations of Daily Living Activities in Patients With Venous Stasis Ulcers Undergoing Compression Bandaging: Problems With the Concept of Self-bandaging. Wounds. October 2007;19:255-257.
10 More than the Eye Can See
Dr. Kirsner’s Comments:
Dermatology is the most visual of specialties, yet this aspect of dermatology is both a blessing and a curse. It allows the novice to assume expertise but also provides an easier maker for disease activity and progression.
Wound healing is similar. The clinical outcome for most wound healing studies is complete healing, as determined by visual inspection. However, both injury and repair occur at a microscopic and genomic level. Additionally, many products are aimed at improving the healing process and may not result in complete healing. For example, products aimed at improving the wound bed may reduce infection and therefore may not result in complete healing.
Measuring various outcomes may be important. Additionally, using surrogate endpoints for healing may aid in preliminary data collection and reduce the initial costs of emerging therapies. Marco Romanelii and colleagues examine objective methods to measure healing. These will be increasingly important in both research endeavors and clinical activities.
Synopsis of the Research:
The question of how well a wound is healing boils down to whether it is shrinking in size, with proper tissue recovery and no signs of infection. Increasingly, wound specialists are turning to technology to help find answers.
From venous leg ulcers to pressure lesions, standardized, objective methods of assessing wound healing are emerging. As a group of Italian wound specialists describe in a recent review article on the subject, technologies such as dedicated wound photography, laser Doppler perfusion imaging, transcutaneous oximetry and others can provide clinically important information about the health of injured tissue.
However, other key assessment tools require only a ruler and a sharpened pencil. Recording the product of a wound’s length by width to determine its area — and whether that number is getting smaller with treatment — has been shown to be a useful gauge of healing for venous leg ulcers, according to the article. “Of all the healing rate parameters assessed, early percent reduction in wound area has been the most reliable in predicting complete venous ulcer healing.”
A similar rule of thumb applies to patients with pressure ulcers, for whom percent reduction in pressure area is a strong predictor of healing prognosis during the first 2 weeks of treatment, and for patients with diabetic foot ulcers, the researchers write.
Optimal wound assessment hinges on the development of a “uniform, standardized, and well-established” combination of noninvasive measurements, the researchers wrote. “The objective assessment of chronic wounds during tissue repair will become a specific aspect within wound management, which will not replace the clinical assessment of expert caregivers, but may bring numerous advantages in terms of understanding and awareness of each wound management challenge,”
SOURCE: Marco Romanelli, M.D., Ph.D.; Valentina Dini, M.D.; Maria Stefania Bertone, N.T.; Cinzia Brilli, R.N. Outcomes Research — Measuring Wound Outcomes. Wounds. November 2007;19:294-298.
Skin & Aging’s sister journal Wounds is the nation’s leading wound care research journal, and it’s the major source of current research, treatment methodology, and protocol in the field of wound care. In addition, this journal is the standard reference tool for those healthcare professionals who are leaders in establishing wound care programs and treatment centers both nationally and internationally.
This month, we bring you the top 10 selections from the whole body of research published in Wounds in 2007.
Dermatologist and wound care expert, Dr. Robert Kirsner, who is Section Editor for Wounds and an Editorial Advisory Board Member for Skin & Aging, selected the following research findings as the most relevant to dermatology. Read on for Dr. Kirsner’s commentary on the relevance of this research as well as a synopses of these wound care findings.
1 The Year of the Pressure Ulcer: Understanding Who’s At Risk
Dr. Kirsner’s Comments:
This year may be the year of the pressure ulcer. The reason for this is that the federal government has mandated that hospital-acquired pressure ulcers not be reimbursed by CMS starting in October 2008.
Of all chronic wounds, pressure ulcers are the most common and the most costly to the Medicare system. This is significant and is one of 9 “quality measures” that the government wishes to implement this year.
Others of importance to dermatologists may include surgical site infections. This is significant because one out of every five Medicare-age hospitalized patients will develop a pressure ulcer during their hospital stay. Therefore, it is paramount to identify the patients at greatest risk and institute risk prevention strategies to obviate the development of these costly pressure ulcers. Often, at-risk patients are thought to have significant cognitive impairment. However, even mentally intact patients are at risk as demonstrated by Magalhães et al.
Risk factors such as humidity, activity, mobility, friction and shear can be assessed accurately by prediction scales such as the Braden scale. These factors are known to be important in pressure ulcer development. Monitoring for these factors and then implementing preventive strategies can lessen ulcer development and the financial impact of impending regulations.
Synopsis of the Research:
Pressure ulcers are blamed for the deaths of an estimated 60,000 patients a year in the United States. Clinicians do not fully understand which people are most likely to develop the condition, but Brazilian researchers have shed some light on the problem.
Marta G. Magalhães, M.D., and her colleagues at the Hospital das Clinicas Samuel Libanio, in Pouso Alegre, looked for the risk factors for pressure ulcers in 40 elderly, hospitalized patients (average age above 70 years) without evidence of significant cognitive impairment. Of those, 20 had been diagnosed with at least one ulcer, most of which were classified as Stage II or Stage I.
The most frequent co-morbidities in ulcer patients were hypertension, diabetes, dyslipidemia and heart failure, the researchers said. Reasons for hospitalization included hip fracture, heart failure, pneumonia, trauma, airway disease and other ailments.
Ulcer patients spent about 10 days longer in the hospital, on average, than patients without the lesions (23.2±18.8 vs. 13±10.4 days), the researchers found. However, this difference in hospital stays did not reach statistical significance.
Patients who developed ulcers had significantly lower scores on the Braden Scale — which takes account of the intensity and duration of pressure, as well as tissue tolerance — than did those who did not develop the lesions, according to the researchers. The investigators set Braden score of 18 as a threshold so that 90% of patients at risk for a pressure ulcer would be included in the analysis.
The researchers found that moisture, activity, mobility and shear force and friction were statistically significant risk factors for development of a pressure ulcer (P<0.05).
Intriguingly, although sex has not been previously identified as a risk factor for pressure ulcers, Dr. Magalhães’s group found that 14 (70%) of the patients who developed ulcers were women.
“Data from the present study illustrate that older patients without significant cognitive impairment have increased risk factors for developing pressure ulcers,” concluded the researchers.
SOURCE: Marta G. Magalhães, M.D.; Alfredo Gragnani, M.D., Ph.D.; Daniela F. Veiga, M.D., et al. Risk Factors for Pressure Ulcers in Hospitalized Elderly without Significant Cognitive Impairment. Wounds. January 2007;19:20-24.
2 The Year of the Pressure Ulcer: Reducing Risk
Dr. Kirsner’s Comments:
Offloading is the standard of care for patients with pressure ulcers and for diabetic neuropathic foot ulcers. The emerging importance of pressure ulcers in the hospital setting and its rapid and quick treatment are imperative. Therefore, understanding when a person is at risk because of increased pressure is important.
Scales developed to predict risk, such as the Braden ad Norton scales, are helpful, but direct measurement of pressure to help design a critical off loading plan is needed.
Pressure sensing devices have been developed experimentally to try to assist clinicians in treating patients with pressure. Their utility in clinical practice is limited, but the need exists for an everyday, easy-to-use, inexpensive device to monitor pressure. Ideally, this pressure sensing device might provide alerts or alarms as well and have collectable data to download and analyze to provide a basis for continuous quality improvement.
Synopsis of the Research:
Pressure ulcers are a major source of morbidity for diabetics and bedridden patients. The lesions result from mechanical stress on and lack of blood flow to skin that has become compressed between the skeleton and a hard surface such as a wheelchair cushion, shoe inner or a mattress.
Recent advances in pressure-sensing technology are enabling clinicians to better prevent pressure ulcers. These devices, which include sensors that can be placed inside shoes and total contact casts to measure foot offloading, or placed under the buttocks to measure sitting pressure, can give doctors a detailed picture of where particular patients are at highest risk of developing an ulcer.
As Amit Gefen, Ph.D., a biomedical engineer at Tel Aviv University in Israel describes in a recent review article in Wounds, “visualization of pressure data is commonly done by means of color-coded diagrams, which show the area of contact (under the foot or buttocks) with regions of high pressure marked using ‘warm’ colors (red or yellow), and regions of low pressure marked using ‘cold’ colors (blue or green).”
However, Dr. Gefen adds, the data also can be presented as isobars and, less commonly, three-dimensional topographical maps. Commercially available software can perform pressure analysis, calculating contact area, compression force peak pressure and other parameters. All these data can be collected in real time at the point of care.
As Dr. Gefen explained, pressure measurements help clinicians and patients in two ways. The technology can provide feedback to patients with nerve damage, from diabetic neuropathy, for example, that has deadened sensation in a body part. It can also help evaluate the suitability of a wheelchair cushion or other padding in order to provide a patient the most comfortable fit —and one less likely to cause a pressure ulcer.
“Body-support pressure measurement systems should be considered a practical tool for protecting insensitive patients from diabetic foot ulcers and sitting-acquired pressure ulcers,” Dr. Gefen wrote. “The computerized pressure-sensing devices currently available on the market … provide real-time quantitative and objective feedback to the clinicians, which allows on-the-spot decision-making during patient evaluation.
SOURCE: Gefen, Amit, Ph.D. Pressure-Sensing Devices for Assessment of Soft Tissue Loading Under Bony Prominences: Technological Concepts and Clinical Utilization. Wounds. December 2007;19:350-362.
3 Improving Diagnostic Accuracy of Swab Cultures
Dr. Kirsner’s Comments:
The diagnosis of infection is currently based on clinical evaluation of a wound. Certainly, wounds of that are surrounded by an advancing erythematous border associated with pain, tenderness and warmth are suggestive of a wound infection. However, other situations exist in which bacteria within the wound may be of importance. For example, in the absence of infection critical colonization may impede healing.
In this situation, bacteria could be in numbers large enough to prevent a wound from healing but not be tissue invasive or cause a host response. These patients may experience failure to heal and the only signs might be increased drainage.
Better diagnostic tests are needed to diagnose infection in those cases and to direct antibiotic therapy. Targeted antibiotic therapy relies on culture results. Therefore, the technique of culturing is important.
Gardner and colleagues reported that technique of culturing called the Levine technique can produce superior culture results. Levine’s techniques involves collecting swab cultures by rotating a swab over a 1 cm2 area of the wound with sufficient pressure to extract fluid from the wound.
This technique is superior to other culture techniques and is currently the preferred culture technique. Of note, anesthesia with EMLA may have antibacterial properties and is not recommended prior to obtaining cultures.
Synopsis of the Research:
Semiquantitative swab cultures provide less accurate information about both the presence and type of bacteria in wounds than do quantitative methods, a recent study found. However, the researchers say, even the more sophisticated sampling must be performed properly to assure good test results.
Sue E. Gardner, R.N., Ph.D., of the University of Iowa College of Nursing, and her colleagues sought to compare semiquantitative culturing with quantitative culturing in 44 chronic wounds. Swab cultures were conducted with Levine’s technique.
Using receiver operating characteristic curve analysis, the researchers found that semiquantitative swab cultures had an area under the curve (AUC) of about 0.64 — not much higher than the 0.5 figure reflective of chance (P=0.0501). The AUC for quantitative cultures, however, was 0.821 (P=0.0128).
Similarly, semiquantitative cultures showed less concordance with tissue cultures at recovering all organisms present in a wound than did quantitative cultures (57% vs. 72%).
The researchers acknowledged that semiquantitative cultures are simpler and less costly to analyze than quantitative samples. But, they added that the lack of precise information the semiquantitative tests provided calls into question how the results should be interpreted.
“Use of a semiquantitative swab culture is of less value in guiding wound care decisions than a quantitative swab culture because the semiquantitative swab provides less accurate information regarding the true bacterial burden of the wound tissue,” the researchers wrote. “However, care must be taken to collect swab specimens in a manner that insures the acquisition of microbes from within the wound tissue such as that provided with Levine’s technique.”
The authors noted that local anesthetic agents have been shown to affect the validity of swab cultures by killing bacteria. As a result, they recommended using preservative-free 1% lidocaine that had been applied no more than 2 hours prior to sampling.
SOURCE: Sue E. Gardner, R.N., Ph.D.; Rita Frantz, R.N., Ph.D.; Stephen L. Hillis, R.N., Ph.D., et al. Diagnostic Validity of Semiquantitative Swab Cultures. Wounds. February 2007;19:31-38.
4 Chronic Wounds: Which Heal, Which Don’t — Using Your Crystal Ball
Dr. Kirsner’s Comments:
Predicting which wound will heal and which won’t is important to ensure superior patient compliance as well as for offering more rapid and efficacious use of adjuvant therapy. Factors such as wound size and wound duration have been eloquently shown to be predictive of healing both diabetic foot and venous leg ulcers.
For example: A venous leg ulcer that is less than 6 months duration and smaller than 5 cm2 is likely (93%) to heal with standard of care (which is multilayered compression bandages). While a wound with large size (>5 cm2) and long duration (present >6 months) is unlikely to heal (13% with standard of care).
Understanding these factors helps stratify risk, enables better comparison of outcomes, and allows clinicians to use judicious adjunctive therapy in a more cost- effective manner.
Jones et al added to the literature by finding that insurance status and socioeconomic status (Medicaid insurance) and race (non-white) are also predictive of failure to heal. These patients are greater risk for having problematic wounds. Therefore, rapid intervention is critical to improve outcomes in this subset of patients
Synopsis of the Research:
Many factors, from the quality of treatment to patients’ race and the source of their health insurance, appear to influence the likelihood that their chronic wounds will heal swiftly.
A retrospective study looked for predictors of fast- and slow-healing wounds in 400 men and women with three kinds of chronic lesions:
1. pressure
2. diabetic
3. venous ulcers.
These lesions were treated at four different institutions ranging from a teaching hospital to a wound care clinic.
Of the total, 51 (12%) experienced healing within 3 weeks of starting treatment. Among the 347 patients with “nonhealing” ulcers, 195 (56%) wounds did not resolve within the 6-month study period.
Dr. Jones’s group confirmed several well-known risk factors for poorly healing wounds, including larger, deeper lesions and ulcers with significant exudates, yellow slough and black eschar. Patients whose wounds showed multiple signs of infection within the first 3 months also experienced protracted healing, as did those who repeatedly received antibiotics during the study.
Interestingly, the investigators said, wounds treated more frequently with antimicrobial dressings also appeared to be less likely to heal rapidly, as did lesions that were mechanically debrided. Finally, racial minorities and patients with Medicaid were more likely to be non-healers than whites and those with other forms of insurance.
Factors linked to rapid healing included treatment with commercial cleaning products, being obese (as opposed to being malnourished) and having smaller, shallower wounds, having more than one ulcer and having ulcers linked to peripheral vascular disease or deep vein thrombosis.
Although some risk factors for stubborn ulcers are beyond the control of clinicians, the researchers say the results suggest that healthcare providers can do a better job of managing chronic wounds.
“Earlier identification and referral for treatment might lead to improved healing rates for some patients,” they wrote. “Remaining factors require the attention of those delivering wound care services. These include more carefully matching wound characteristics to selected dressings, and eliminating the use of mechanical debridement and cytotoxic agents.
These results also demonstrate the need for more complete documentation of wound characteristics for selection of appropriate interventions and for better monitoring of healing progression.”
SOURCE: Katherine R. Jones, R.N., Ph.D., FAAN; Kristopher Fennie, Ph.D., M.P.H.; Amber Leniha. Chronic Wounds: Factors Influencing Healing Within 3 Months and Nonhealing After 5–6 Months of Care. Wounds. March 2007;19:551-561.
5 The Blockbuster: Insights into Mechanisms
Dr. Kirsner’s Comments:
Negative pressure wound therapy (NPWT), a.k.a. vacuum-assisted closure (VAC) is a commonly employed adjuvant to heal large and deep wounds. A blockbuster device, NPWT has annual sales of more than $1 billion. The NPWT employs 125 mmHg negative pressure to a wound and has been shown in large series and more recently in randomized controlled trials to speed the healing of various wound types.
Clinically appealing because of the collection of large amounts of drainage, the mechanism by which the vacuum works, is more hypothesized than truly known. Among the factors thought to be important to its benefit include the physiologic stretching of cells, which renders them more productive, the collection of exudate that in many situations may have a negative effect on healing, and the stimulation of angiogenesis.
Norbury et al contributed to our knowledge of the mechanisms by which NPWT works by studying porcine full-thickness wounds. They found that NPWT reduced the number of peripheral monocytes and neutrophils with accompanying reduction in inflammatory cytokines such as IL-8, tumor necrosis factor alpha and transforming growth factor beta.
This information fits very well into one of the paradigms of why chronic wounds develop. n addition to cellular senescence, bacterial burden and deficient and/or unavailable growth factors, inflammation and the subsequent development of a proteolytic environment in the wound are thought causal in maintaining a chronic wound state. Reducing inflammatory cytokines would therefore be helpful in altering this abnormality.
Synopsis of the Research:
Porcine wounds treated with vacuum-assisted closure (VAC) therapy show less evidence of local and systemic inflammation than those treated with a moist dressing alone, a recent study suggested.
The study, by researchers at Kinetic Concepts, Inc., makers of the VAC device (also called negative pressure wound therapy), looked at the technology’s effect on inflammatory markers in 10 pigs given 2 “full-thickness” excisional wounds 5 cm in diameter. Six of the animals were treated with vacuum therapy and four received moist dressings without negative pressure.
Wounds treated with VAC appeared to heal faster than those in the control animals, the researchers noted. Blood tests of the treated pigs 36 hours after wounding revealed significantly lower amounts of monocytes (0.2 vs. 0.9 per nl; P<05). At 84 hours after wounding, treated animals also had fewer circulating neutrophils (5.4 vs. 13.6 per nl; P<0.05) than controls.
Statistically significant differences were seen in serum levels of INF-g and interleukin-6 (IL-6), although no differences were observed for other interleukins or in levels of tumor growth factor-b(TGF-b) or tumor necrosis factor-a.
Tests of fluid from the wounds themselves showed statistically significant reductions in IL-8 in the vacuum-treated lesions but only at the 12-hour mark, the researchers say. Concentrations of TGF-b also were lower in the fluid of VAC-treated wounds than in the control wounds (P<0.05) at the 132- and 180-hour mark.
“The results of this study support the hypothesis that [VAC Therapy] attenuates the early inflammatory response in a porcine acute wound healing model,” the researchers wrote. “Collectively, these responses corresponded to increased wound closure.”
SOURCE: Kenneth Norbury, B.S., Ph.D., and Kris Kieswetter, B.S., Ph.D., M.B.A. Vacuum-assisted Closure Therapy Attenuates the Inflammatory Response in a Porcine Acute Wound Healing Model. Wounds. April 2007;19:97-106.
6 Hope for Large Venous Ulcers
Dr. Kirsner’s Comments:
Skin grafting has been employed for centuries to cover non-healing wounds. Used in dermatology, primarily to improve the cosmetic outcome of full-thickness wounds, split-thickness skin grafts (STSG) have the benefit of more rapid take because of their relatively thin nature. However, they are generally employed for refractory or non-healing chronic wounds and controlled trials of autologous STSG have been not forthcoming. Additionally, the use of engineered skin which has the benefit of an off- the-shelf capability has in many cases precluded the use of autologous STSG that require the creation of the second wound with associated morbidity. Yet, the utility of split skin graft cannot be denied; this type of graft is still routinely practiced, so understanding the outcomes of its use is critical.
Jankunas et al now provide some objective data regarding the utility of STSG in treating venous leg ulcers. Although not a randomized study, they prospectively evaluated more than 70 patients with extremely large (50 cm2) venous ulcers. Two-thirds of the wounds healed after STSG and others improved compared with no complete healing in the control group that didn’t undergo grafting.
This report serves to reinforce our clinical perception of the benefits of STSG. Without doubt, in large ulcers of long duration, STSG should be considered as an option.
Synopsis of the Research:
Skin grafts are superior to non-surgical care for treating chronic venous leg ulcers, according to a recent study by Lithuanian researchers. The study found that patients with large ulcers who underwent grafts were more likely to experience complete epithelialization, a reduction in lesion size and to have the wounds remain closed 6 months after treatment.
Chronic venous leg ulcers (CVLUs), which generally result from venous insufficiency, are a significant source of morbidity in Lithuania, where nearly 2% of the population suffers from the condition, and elsewhere. They occur about twice as frequently among people over age 65 years.
In the latest study, Vytautas Jankunas, Ph.D., M.D., from Klaipeda County Hospital and his colleagues compared the effectiveness of partial-thickness skin autografting (ADP) with conservative care — hydrocolloid bandages and compression therapy — in 71 patients with CVLUs that had not resolved with other therapy.
None of the 31 patients who received conservative care saw their ulcers heal completely, the researchers reported. Average ulcer size in this group fell in 14 patients but rose in 17, while wound size shrank to 171 cm2 from 182 cm2 over the 6-month study period (P>0.5).
Of the 40 patients who underwent ADP followed by compression therapy, however, 27 (67%) had complete epithelialization of their ulcers, with the average wound area falling to 16 cm2 from 279 cm2 within 2 to 3 weeks after treatment. “In comparison with the previous area, the current area was rather small and did not (or was insignificant) influence patient quality of life,” the researchers wrote.
The researchers also looked at the bacteria present in the CLVUs, finding that Staphylococcus aureus and Pseudomonas aeruginosa were the most common organisms.
“Although the patients were taking medications to improve microcirculation, venous flow, and lymph drainage, the authors believe that the compressive therapy was responsible for the 6-month period where there were no cases of new ulcers opening in the group of operated patients,” they wrote.
SOURCE: Vytautas Jankunas, Ph.D., M.D.; Rokas Bagdonas, Ph.D., M.D.; Donatas Samsanavicius, M.D.; Rytis Rimdeika, Ph.D., M.D. An Analysis of the Effectiveness of Skin Grafting to Treat Chronic Venous Leg Ulcers. Wounds. May 2007;19:128-137.
7 More Arrows in your Quiver: PHMB, (Polyhexamethylene Biguanide)
Dr. Kirsner’s Comments:
The presence of bacteria in non-healing wounds and their potential effect on inhibiting healing has led to clinical agents used to address altering wound bacteria. A number of agents are currently available to treat bacteria within wounds including various silver dressings and cadexomer iodine preparations.
A relative newcomer to the antimicrobial scene has been polyhexamethylene biguanide (PHMB). This is a commonly employed household antiseptic used in various cleansers including pool cleansers as well as contact lens solution. It is therefore safe and well tolerated and thought to have little, if any, toxicity.
More recently, several dressings are currently available on the market that incorporate PHMB in the dressing material with labeled indication to prevent bacterial invasion from the outside into the wound. In practice and in animal studies, PHMB also reduced wound bacteria as well. Possessing a broad spectrum of antimicrobial action and little toxicity, PHMB is another option in combating excessive bacteria for wounds either critically colonized or infected.
Synopsis of the Research:
Wound dressings containing the antimicrobial agent PHMB promote cost-effective healing, according to a recent study which suggests that although the dressings are initially more expensive than conventional wet-to-dry gauze, they may pay for themselves over time.
The randomized, controlled study by Gerit Mulder, D.M.P., M.S., at the University of California, San Diego, comprised 12 patients with wounds of various causes, including venous statis, trauma, diabetes and other conditions. Results from four patients were used for a cost-effectiveness analysis.
Treatment with biosynthesized cellulose wound dressings (XCell) containing 0.3% PHMB led to an average decrease in wound size of 42% (to 4.57 cm2 from 6.79 cm2). Two, relatively small wounds healed completely during the study while two others expanded slightly, the researchers say. The average duration of use of PHMB was 25 days (range 5 to 52 days).
Although the antimicrobial dressings were initially more expensive than wet-to-dry gauze, they were more cost-effective when considering the time to achieve debridement of 50% or better. “The average cost of material was calculated to be $5.99 to $9.01 per day with the wounds demonstrating improvement or healing,” they write. The researchers did not include other costs of treatment, such as those involving clinic visits and staff time.
“The limited amount of information on the ability of antimicrobial dressings to significantly affect the healing process and wound closure supports the need for well designed and adequately powered clinical trials to determine the true role of these devices in the treatment of chronic wounds,” the authors concluded. “Current information and publications indicate a potential benefit regarding the use of these products in wound where bacterial burden may be delaying or impeding wound closure.”
SOURCE: Gerit D. Mulder, D.P.M., M.S.; Joseph P. Cavorsi, M.D.; Daniel K. Lee, D.P.M. An Analysis of the Effectiveness of Skin Grafting to Treat Chronic Venous Leg Ulcers. Wounds. July 2007;19:173-182.
8 Honey Sweet Death to Microbes
Dr. Kirsner’s Comments:
A spoonful of sugar may be the medicine. English researchers have confirmed that medicinal honey has significant antibacterial prowess against several strains of virulent pathogens, including those resistant to multiple antibiotics. Used for centuries, honey has been purported to speed healing of various wound types. Honey is thought to work because of its occlusive nature and its osmotic properties.
For many, honey has been thought by some to present an inexpensive alternative in developing countries to more occlusive expensive dressings. Not all honeys are equivalent. A specific brand of honey, the so-called Manuka honey predominantly sourced from Leptospermum species from New Zealand and Australia has been found to have other properties that may render it superior to other honeys. Specifically, this Manuka honey appears to have superior and broad- spectrum antimicrobial properties. To the average person, this may be seen as the lesser need for preservatives within honey. However, to patients with wounds, this antimicrobial action may have a beneficial effect on wound healing.
The first honey bandage to hit the market in the United States is called Medihoney. The public’s interest in and desire for natural products will likely draw significant interest in this product. The low-tech nature may not be as attractive to physicians and the hope is that well-done studies like those published by George and Cutting will help clarify a sticky subject.
Synopsis of the Research:
The researchers tested one form of medicinal honey, Medihoney (Medihoney Pty LTD), which is made in Australia from the Manuka plant, a member of the Leptospermum family.
Honey is believed to kill bacteria in at least four ways, according to the researchers.
1. Its high sugar content and low water activity promotes osmotic action
2. its acidic pH (3.2-4.5) blocks the growth of germs
3. it contains the enzyme glucose oxidase that stimulates the production of hydrogen peroxide; and
4. it may have plant-derived molecules, yet unidentified, that attack microorganisms.
The researchers exposed 130 bacteria isolates, including multidrug resistant Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus, to various concentrations of Medihoney. They identified the minimum inhibitory concentrations (MIC) of the product for each strain to determine its antibiotic efficacy.
The effective concentration of Medihoney ranged from 4% to achieve a MIC of 90% for many bugs, such as methicillin-resistant and methicillin-susceptible S. aureus, to 14% for a MIC of 90% for extended-spectrum b-lactamase-positive P. aeruginosa.
Although the latest work was in vitro, the researchers note that a previous study by Johnson, et al (J Am Soc Nephrol. 2005;16:1456-1462) found that Medihoney was as effective as mupirocin at preventing catheter-associated infections.
“Given that mupirocin can reduce infection rates by at least 7 to 13 fold,” they wrote, “the prospect that Medihoney will prove to be an effective prophylactic is extremely helpful.”
SOURCE: Narelle May George; Keith F. Cutting. Antibacterial Honey(Medihoney): in-vitro Activity Against Clinical Isolates of MRSA, VRE, and Other Multiresistant Gram-negative Organisms Including Pseudomonas aeruginosa. Wounds. September 2007;19:231-236.
* Mr. Cutting disclosed that he has received research funding from Medihoney Pty.
9 Patient: Don’t Heal Thyself
Dr. Kirsner’s Comments:
The standard of care of venous leg ulcers is a use of multilayer compression bandages. Without compression bandages the likelihood of healing drops dramatically for patients with venous ulcers. These dressings are typically applied anywhere from twice weekly to every other week by skilled professionals. Unfortunately, this requires the patient to either have a home health nurse to visit him or to make visits to the office to have the bandages changed.
Conceptually, self-bandaging would be an alternative to this. However, the skills of applying a multilayer compression bandage are numerous, and potential adverse outcomes may result. It appears from the work of Fife and colleagues that asking patients to apply their own dressings in unrealistic. Studying a group of more than 500 patients, they found more than 50% needed assistance with routine activities of daily living. It is hard to imagine that this population of patients could manage dressing applications. This is critical information for physicians who might ask patients to apply their own bandages and payers who do not pay for alternative methods for dressing applications.
Synopsis of the Research:
More than half of patients with venous stasis ulcers reported having trouble going to the bathroom, bathing, walking and performing other routine activities — difficulty that may translate into their inability to properly dress their wounds.
The results come from a database analysis of more than 7,250 wound patients at 29 treatment centers. Of those patients, 547 were identified as having venous stasis ulcers.
Led by Caroline Fife, M.D., of the University of Texas Health Science Center in Houston, the researchers found that 55% of the patients required some help with activities of daily living, chiefly using the toilet and getting dressed.
“If a patient cannot dress him or herself or has a problem toileting, it is likely that the person will have problems applying a compression bandage, presuming that he or she has the knowledge to do so, which is a separate issue,” the researchers wrote. “Thus, more than half of these patients are unlikely to be able to participate in the necessary therapy to treat their venous stasis ulcers unless the help of family members or healthcare professionals is available.”
The authors noted that the cost to the U.S. healthcare system of treating venous stasis ulcers is estimated to range from $2.5 billion to $3.5 billion per year.
“If patients cannot afford the costs of basic compression bandaging and cannot self-bandage, costs to the healthcare system and patients alike will ultimately rise as ulcers become far less likely to heal,” the authors concluded.
SOURCE: Caroline Fife, M.D., B.S.; David Walker, C.H.T.; Brett Thomson, B.S.; Marissa Carter, Ph.D., M.A. Limitations of Daily Living Activities in Patients With Venous Stasis Ulcers Undergoing Compression Bandaging: Problems With the Concept of Self-bandaging. Wounds. October 2007;19:255-257.
10 More than the Eye Can See
Dr. Kirsner’s Comments:
Dermatology is the most visual of specialties, yet this aspect of dermatology is both a blessing and a curse. It allows the novice to assume expertise but also provides an easier maker for disease activity and progression.
Wound healing is similar. The clinical outcome for most wound healing studies is complete healing, as determined by visual inspection. However, both injury and repair occur at a microscopic and genomic level. Additionally, many products are aimed at improving the healing process and may not result in complete healing. For example, products aimed at improving the wound bed may reduce infection and therefore may not result in complete healing.
Measuring various outcomes may be important. Additionally, using surrogate endpoints for healing may aid in preliminary data collection and reduce the initial costs of emerging therapies. Marco Romanelii and colleagues examine objective methods to measure healing. These will be increasingly important in both research endeavors and clinical activities.
Synopsis of the Research:
The question of how well a wound is healing boils down to whether it is shrinking in size, with proper tissue recovery and no signs of infection. Increasingly, wound specialists are turning to technology to help find answers.
From venous leg ulcers to pressure lesions, standardized, objective methods of assessing wound healing are emerging. As a group of Italian wound specialists describe in a recent review article on the subject, technologies such as dedicated wound photography, laser Doppler perfusion imaging, transcutaneous oximetry and others can provide clinically important information about the health of injured tissue.
However, other key assessment tools require only a ruler and a sharpened pencil. Recording the product of a wound’s length by width to determine its area — and whether that number is getting smaller with treatment — has been shown to be a useful gauge of healing for venous leg ulcers, according to the article. “Of all the healing rate parameters assessed, early percent reduction in wound area has been the most reliable in predicting complete venous ulcer healing.”
A similar rule of thumb applies to patients with pressure ulcers, for whom percent reduction in pressure area is a strong predictor of healing prognosis during the first 2 weeks of treatment, and for patients with diabetic foot ulcers, the researchers write.
Optimal wound assessment hinges on the development of a “uniform, standardized, and well-established” combination of noninvasive measurements, the researchers wrote. “The objective assessment of chronic wounds during tissue repair will become a specific aspect within wound management, which will not replace the clinical assessment of expert caregivers, but may bring numerous advantages in terms of understanding and awareness of each wound management challenge,”
SOURCE: Marco Romanelli, M.D., Ph.D.; Valentina Dini, M.D.; Maria Stefania Bertone, N.T.; Cinzia Brilli, R.N. Outcomes Research — Measuring Wound Outcomes. Wounds. November 2007;19:294-298.
