Hiroe Koyanagi

Do nutritional markers in wound fluid reflect pressure ulcer status

Evaluation of wound fluid characteristics for pressure ulcer (PU) assessment in clinical settings remains subjective, requiring considerable expertise. This cross‐sectional study focused on nutritional markers in wound fluid as possible objective tools and investigated whether they reflect the PU status according to the healing phase, infection, and granulation, especially after adjusting for serum values. Twenty‐eight patients with 32 full‐thickness PUs were studied. The concentration of albumin, total protein, glucose, and zinc in wound fluid were measured. For PU status, the healing phases and infection were evaluated by clinical signs, and the degree of granulation tissue formation was determined as the hydroxyproline concentration. The wound fluid/serum ratio for albumin was significantly lower during the inflammatory phase than during the proliferative phase (p=0.020). Infected wound fluid contained less glucose (0.3–1.0 mmol/L) than noninfected ones did (5.0–7.6 mmol/L) in an intraindividual comparison of three cases. The wound fluid/serum ratio for glucose was negatively correlated with hydroxyproline level in the proliferative phase (ρ=−0.73, p=0.007), while zinc level in wound fluid showed a positive correlation (ρ=0.61, p=0.028). Our results suggest that these traditional nutritional markers in wound fluid, especially wound fluid/serum ratio may be useful to evaluate local PU status.

Estimation of protein loss from wound fluid in older patients with severe pressure ulcers

OBJECTIVE Protein loss from wound fluid is usually recognized as one of the factors contributing to the deterioration of the nutritional status in older patients with severe pressure ulcers. We quantified the protein loss owing to pressure ulcers and investigated associations with wound-related factors and nutritional status. METHODS This cross-sectional study included 25 patients (>or=60 y) from 10 institutions, with full-thickness pressure ulcers. Wound fluid was collected once after accumulating beneath a film dressing. The amount of protein loss per day was estimated by the volume of wound fluid per hour and the total protein concentration in the wound fluid. Wound evaluations and nutritional assessments were performed. Correlations between variables were obtained using Spearmans rank correlation. RESULTS The median age of the patients was 79 y (range 61-100), and median body mass index was 19.6 kg/m(2) (12.2-24.9). The median amount of protein loss was 0.2g/d (0.04-2.1), which corresponded to 0.01 g x kg(-1) x d(-1) (<0.01-0.04) and 0.6% (0.1-13.8) of protein intake. Four wounds characterized as infected or surgically debrided lost 1.5-2.1g of protein per day, which was substantially higher than other wounds lost. Protein loss was correlated with wound severity including area, depth, the wound severity score, and infectious markers (all Ps<0.05), but not with body mass index or arm muscle circumference (P>0.05). CONCLUSION The amount of protein loss could be small and thus may not be related directly to nutritional status, although it increased as the wound became more severe.

Wound blotting: A convenient biochemical assessment tool for protein components in exudate of chronic wounds

Because wound exudate includes secreted proteins that affect wound healing, its biochemical analysis is useful for objective assessment of chronic wounds. Wound blotting allows for collection of fresh exudate by attaching a nitrocellulose membrane onto the wound surface. To determine its applicability for several analysis methods and its executability in clinical wound assessment, this study comprised an animal experiment and clinical case reports. In the animal experiment, full‐thickness wounds were created on the dorsal skin of mice, and exudate samples were collected daily by a conventional method and by wound blotting. Extremely small but adequate volumes of exudate were collected by wound blotting for subsequent analysis in the animal experiments. Immunostaining showed the concentration and distribution of tumor necrosis factor (TNF) α. The activity of alkaline phosphatase was visualized by reaction with chemiluminescent substrate. The TNF distribution analysis indicated three different patterns: wound edge distribution, wound bed distribution, and a mostly negative pattern in both the animal and clinical studies, suggesting association between the TNF distribution pattern and wound healing. Our results indicate that wound blotting is a convenient method for biochemical analysis of exudate and a candidate tool with which to predict the healing/deterioration of chronic ulcers.

Concurrent validation and reliability of digital image analysis of granulation tissue color for clinical pressure ulcers.

Granulation tissue color is one indicator for pressure ulcer (PU) assessment. However, it entails a subjective evaluation only, and quantitative methods have not been established. We developed color indicators from digital image analysis and investigated their concurrent validity and reliability for clinical PUs. A cross‐sectional study was conducted on 47 patients with 55 full‐thickness PUs. After color calibration, a wound photograph was converted into three images representing red color: erythema index (EI), modified erythema index with additional color calibration (granulation red index [GRI]), and , which represents the artificially created red–green axis of L*a*b* color space. The mean intensity of the granulation tissue region and the percentage of pixels exceeding the optimal cutoff intensity (% intensity) were calculated. Mean GRI (ρ=0.39, p=0.007) and (ρ=0.55, p<0.001), as well as their % intensity indicators, showed positive correlations with a* measured by tristimulus colorimeter, but erythema index did not. They were correlated with hydroxyproline concentration in wound fluid, healthy granulation tissue area, and blood hemoglobin level. Intra‐ and interrater reliability of the indicator calculation using both GRI and had an intraclass correlation coefficient >0.9. GRI and from digital image analysis can quantitatively evaluate granulation tissue color of clinical PUs.

Combination of thermographic and ultrasonographic assessments for early detection of deep tissue injury

Early detection and intervention of deep tissue injury are important to lead good outcome. Although the efficiency of ultrasonographic assessment of deep tissue injury has been reported previously, it requires a certain level of skill for accurate assessment. In this study, we present an investigation of the combination of thermographic and ultrasonographic assessments for early detection of deep tissue injury. We retrospectively reviewed 28 early‐stage pressure ulcers (21 patients) presenting at the University of Tokyo Hospital between April 2009 and February 2010, surveying the associated thermographic and ultrasonographic findings. The wound temperature patterns were divided into low, even and high compared with the surrounding skin. Ultrasonographic findings were classified into unclear layer structure, hypoechoic lesion, discontinuous fascia and heterogeneous hypoechoic area. All 13 ulcers that were associated with low temperature showed good outcome; three ulcers had even temperatures and 12 ulcers showed high temperature on thermographic assessment. The two deep tissue injuries were rated high on thermographic assessment and showed heterogeneous hypoechoic area findings on ultrasonographic assessment. No non‐deep tissue injury lesion was associated with these two findings simultaneously. The combination of thermographic and ultrasonographic assessments is expected to increase the accuracy of the early detection of deep tissue injuries.

Predictive validity of granulation tissue color measured by digital image analysis for deep pressure ulcer healing: a multicenter prospective cohort study

This multicenter prospective cohort study examined the predictive validity of granulation tissue color evaluated by digital image analysis for deep pressure ulcer healing. Ninety-one patients with deep pressure ulcers were followed for 3 weeks. From a wound photograph taken at baseline, an image representing the granulation red index (GRI) was processed in which a redder color represented higher values. We calculated the average GRI over granulation tissue and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) and wound surface (%wound red index 80). In the receiver operating characteristics curve analysis, most GRI parameters had adequate discriminative values for both improvement of the DESIGN-R total score and wound closure. Ulcers were categorized by the obtained cutoff points of the average GRI (≤80, >80), %GRI80 (≤55, >55–80, >80%), and %wound red index 80 (≤25, >25–50, >50%). In the linear mixed model, higher classes for all GRI parameters showed significantly greater relative improvement in overall wound severity during the 3 weeks after adjustment for patient characteristics and wound locations. Assessment of granulation tissue color by digital image analysis will be useful as an objective monitoring tool for granulation tissue quality or surrogate outcomes of pressure ulcer healing.This multicenter prospective cohort study examined the predictive validity of granulation tissue color evaluated by digital image analysis for deep pressure ulcer healing. Ninety‐one patients with deep pressure ulcers were followed for 3 weeks. From a wound photograph taken at baseline, an image representing the granulation red index (GRI) was processed in which a redder color represented higher values. We calculated the average GRI over granulation tissue and the proportion of pixels exceeding the threshold intensity of 80 for the granulation tissue surface (%GRI80) and wound surface (%wound red index 80). In the receiver operating characteristics curve analysis, most GRI parameters had adequate discriminative values for both improvement of the DESIGN‐R total score and wound closure. Ulcers were categorized by the obtained cutoff points of the average GRI (≤80, >80), %GRI80 (≤55, >55–80, >80%), and %wound red index 80 (≤25, >25–50, >50%). In the linear mixed model, higher classes for all GRI parameters showed significantly greater relative improvement in overall wound severity during the 3 weeks after adjustment for patient characteristics and wound locations. Assessment of granulation tissue color by digital image analysis will be useful as an objective monitoring tool for granulation tissue quality or surrogate outcomes of pressure ulcer healing.