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Evaluating the Effectiveness of a Dressing for Use in Malodorous, Exuding Wounds
Patients with chronic wounds - for example, pressure ulcers, leg ulcers, gangrenous wounds, and fungating malignant wounds - are at risk of developing body malodor.1 Although exuding, malodorous wounds are a difficult clinical problem,2 exact data on the incidence and/or prevalence of such wounds are not known. Problems associated with malodor include social isolation, loss of appetite, inhibition of intimacy, and distress for patients and their caregivers.3-6
In chronic wounds, odor is due to tissue degradation or anaerobic bacteria generating odor by emitting compounds such as putrescine, cadaverine, volatile sulphur compounds, and short chain fatty acids, although aerobic bacteria such as Pseudomonas and Klebsiella species also can produce offensive odors.7 Putrescine and cadaverine often are described as acrid-smelling; they are persistent and constantly detectable8 and can cause a vomit or gag reflex.
Through a mechanical process of adaptation, the body protects an individual from being saturated by weak stimuli (smells) by desensitizing sensory cells.9 This may occur in the case of a patient with a malodorous wound but not necessarily for the nurse caring for the patient. Failure to adapt can result in increased sensitivity from repeated exposures to the malodor; this can become a stressor and can eventually elicit health symptoms such as nausea.10 This is commonly reported by patients with fungating breast carcinomas. For many, awareness of a particular smell usually occurs quickly, but for chronic unpleasant odors, this may not be the case.
Preventing or treating microbial colonization or the infection that is causing the offensive smell may achieve odor reduction. This can be accomplished using systemic or topical antibiotics. However, the optimal dose to ensure efficacy is not clear. Other odor-control mechanisms include cleansing the wound, implementing general hygiene measures, and using odor- controlling dressings. These products are designed to act like filters and adsorb odor-causing molecules. The first successful use of charcoal cloth incorporated into gauze and water repellent fabric in the treatment of fungating breast cancer, gangrene, and postoperative colostomy management to reduce the odor was reported in 1976.11 The efficiency of such dressings seems to depend on the presentation of activated charcoal.12-15
Study Dressing
The dressing under evaluation, Carboflex® (ConvaTec, a Bristol-Myers Squibb Company, Princeton, NJ), is a multicomponent wound dressing designed specifically for controlling malodor and wound exudate. The product consists of a skin friendly wound contact layer of nonwoven fibers (Kaltostat® and Aquacel®, both from ConvaTec, a Bristol-Myers Squibb Company, Princeton, NJ) capable of absorbing exudate and maintaining a moist wound environment. Between the wound contact layer and charcoal cloth is a one-way, perforated, water-resistant film. The film protects the charcoal cloth by delaying the passage of fluid through to the cloth; thereby, enhancing the ability of the charcoal to control odor. Above the charcoal cloth is an additional absorbent padding layer of mixed fibers that provides greater security against the problem of fluid strikethrough. An outer, perforated layer delays the passage of fluid through the dressing and completes the structure of the dressing. The aim of this study was to evaluate the effectiveness and performance of the odor-control dressing in the treatment of exuding, malodorous, acute and chronic wounds.
Study Design
This was an open, prospective, noncomparative, multicenter study. Ethical review board approval was obtained for the six centers involved. Patients were included in the study if they presented with an exuding, malodorous (moderate or strong) wound and could give informed consent. Patients were excluded from participating if they had a known history of poor compliance, a known sensitivity to the test product, and multiple malodorous wounds. Patients with dementia or who were unable to participate effectively and those who had entered similar studies before also were excluded. Patients with known olfactory abnormalities, including anosmia (complete loss of olfactory ability) or hyposmia (diminished sense of smell), were excluded from the study.
Measurements
Odor was assessed by both the study nurse and the patient at the initial assessment, at each dressing change prior to removal of the secondary dressings and/or bandages, and after dressing removal but before wound cleansing. The study nurse was at arms' length from the wound when performing odor assessment. Odor was rated using the following verbal rating scale:
Strong = Intolerable
Moderate = Noticeable but tolerable
Minimal = Scarcely noticeable
Absent = No unpleasant smell
In addition, the patient was asked to assess whether the odor was worse, the same, or less than at baseline.
Exudate level was subjectively assessed by the study nurses' observations. In an attempt to standardize measurements, guidelines were followed accordingly. If gauze dressings had been used, the level of exudate based on dressing change frequency would have been:
> 3 days = minimal exudate level
24 to 48 hours = moderate exudate level
< 24 hours = heavy exudate level
At each dressing change, the study nurse subjectively rated the dressings' ease of removal by the level of nonadherence. Photographs were taken on study entry and exit; dressings were changed as clinically indicated.
As part of the initial evaluation, the nurse recorded the condition of the wound bed and estimated the percentage of eschar, slough, granulation tissue, and epithelium present. The surrounding skin also was examined for the presence of maceration, erythema, or pruritus. The same assessment was repeated on completion of the study.
Sample Size
A target sample of 40 patients with exuding, malodorous, chronic or acute wounds was to be enrolled. Five study centers participated in the study. Within the United Kingdom, these included, a tertiary wound research center, a community wound care research center, and an acute hospital. The United States centers included a Veterans Administration medical center and a cancer center. Forty-six patients were recruited, 25 from the United Kingdom and 21 from the United States, respectively.
Methods
After obtaining informed consent, a wound history was obtained and baseline assessments completed. The dressing could be used alone or in combination with a wound filler for deeper wounds. Wounds were assessed at each dressing change. Patients were followed for a maximum of 2 weeks, 10 dressing changes, or healing, whichever was sooner. The dressing frequency was dictated by clinical indication. If the wound became infected during the study, the doctor prescribed systemic antibiotic therapy if considered appropriate and the patient remained in the study. If topical antimicrobial treatment was deemed more appropriate, the patient was withdrawn from the study. Where appropriate, compression therapy was used for ulcers of venous origin; however, because of the frequency of dressing changes required, this was not always the treatment of choice.
Results
Forty-six patients were recruited into the study (see Table 1). Their mean age was 70.7 years, with a higher percentage of male (61%) participants. The mean wound duration was 231.6 weeks. Wounds were predominantly leg ulcers, shallow, and moderately exuding. A majority of wounds previously had been dressed with either an alginate (29%) or gauze and a low-adherent dressing; the average and standard deviation for dressing wear time are shown in Table 2. The greatest numbers of dressing changes were performed on leg ulcers with a mean wear time of 1.76 days (SD = 1.17).
Changes in wound bed condition were assessed by comparing baseline to final evaluation information. In general, study wounds experienced a decrease in wound bed slough matched by an increase in granulation tissue and epithelium (see Table 3).
In order to be recruited into the study, patients had to report wound odor as strong or moderate. All wounds in this study had odor levels described as either moderate (n = 37, 80%) or strong (n = 9, 20%) with moderate (n = 31, 67%) or strong odor (n = 15, 33%) upon dressing removal (see Table 4) while the prestudy dressing was in place. After the study dressing was in place, a nurse assessment indicated that wound odor was minimal or absent before 252 (72%) dressing changes (see Table 4).
Following removal of the dressing when the wound was exposed, odor was reported as minimal or absent on 191 (55%) occasions. The patient's subjective assessment of odor levels recorded an improvement from the beginning of the study for 226 (65%) dressing changes (see Table 4). At the end of the study, exudate management was rated as excellent or good for 82% of patients (see Table 5). The dressing was reported to be comfortable to wear and was rated as excellent or good in 38 (86%) cases. Ease of dressing removal was rated as excellent (54%) and good (36%) by the nurses.
Discussion
Previous research found that wounds most commonly associated with odor are leg ulcers and fungating lesions.13 Confirming these observations, more than half (59%) of the malodorous wounds in this study were leg ulcers. The presence of odor is often linked with tissue degradation - this is reflected in the number of patients presenting with slough/eschar who reported strong or moderate odor at baseline. However, patients reported odor to be minimal or absent in 75% of dressing changes during the study.
Odor was measured in terms of the patients' and nurses' perceptions, which is a subjective measurement that could be affected by many variables, including the natural decline in olfactory sensitivity.16 Interestingly, patient and nurse perceptions of odor appeared similar. This may be partly due to the relationship between patient and nurse during the trial. However, drawing any statistical conclusions from the data for the subject and the investigator was not possible because the odor rating scales were different. Previous authors have recognized the problems associated with subjective measurements and the potential for individual interpretation.17 To date, no device is available to objectively measure odor,7 and although objective physiological tests of smell are described,18 they are difficult to measure in practice. More recent technological advances have the potential to monitor odor more sensitively.19,20 These could be explored and used in any future research that may be initiated.
In addition to managing odor, a key function of charcoal dressings is the management of exudate commonly associated with malodorous wounds. Drawing any specific conclusions from the data regarding wounds of varying etiologies with consideration to wear time and odor was difficult, as the numbers were too small in each group. This issue also could be addressed in a future study. The adsorption efficiency of charcoal decreases when it becomes wet by wound exudate,21 yet this dressing was rated as excellent or good (82%) for exudate management; it was comfortable and easily removed.
Conclusion
The use of this particular odor-control dressing is of benefit to patients with malodorous, exuding wounds of a range of etiologies. By reducing malodor and aiding exudate control, the quality of life of patients with malodorous wounds may improve in terms of their discomfort and feelings of social isolation. In infected malodorous wounds, appropriate treatment of any underlying infection is important. The immediate management of exudate and malodor is equally important. Benefits were apparent in terms of odor reduction reported by patients. Treatment that included the odor-control dressing successfully managed wounds with previously moderate or intolerable odor. Studying larger patient populations and examining the types of organisms that are involved with wound odor would be helpful.
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