Sanae Sasaki

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.

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.

Lower temperature at the wound edge detected by thermography predicts undermining development in pressure ulcers: a pilot study

Undermined pressure ulcers (PUs) are troublesome complications that are likely to delay wound healing. Early skin incision and debridement can prevent the deterioration of undermined PUs, thus it is necessary to identify devitalised tissue areas to determine the appropriate timing for such interventions. This retrospective cohort study evaluated whether a lower temperature at the wound edge than the wound bed and periwound skin, detected by thermography, can predict undermining development in PUs 1 week after the assessment. Twenty‐two participants with category III, IV, or unstageable PUs who were examined by interdisciplinary PU team and were followed up for at least two consecutive weeks were analysed. We found 9/11 PUs without a lower temperature at the wound edge did not develop undermining development, whereas 8/11 PUs with the lower temperature did develop undermining. The relative risk of undermining development after 1 week in PUs with the lower temperature was 4·00 (95% confidence intervals: 1·08–14·7). The sensitivity, specificity, positive predictive value and negative predictive value were 0·80, 0·75, 0·73 and 0·81, respectively. A thermal imaging assessment focusing on a lower temperature pattern at the wound edge may provide sufficient information to predict undermining development.

Biofilm detection by wound blotting can predict slough development in pressure ulcers: A prospective observational study.

Bacteria have been found to form multicellular aggregates which have collectively been termed “biofilms.” It is hypothesized that biofilm formation is a means to protect bacterial cells including protection form the immune response of humans. This protective mechanism is believed to explain persistent chronic wound infections. At times, the biofilms are abundant enough to see, and remove by simple wiping. However, recent evidence has shown that the removal of these visible portions are not sufficient, and that biofilms can continue to form even with daily wiping. In this work, we tested an approach to detect the biofilms which are present after clinically wiping or sharp wound debridement. Our method is based on a variation of impression cytology in which a nitrocellulose membrane was used to collect surface biofilm components, which were then differentially stained. In this prospective study, members of an interdisciplinary pressure ulcer team at a university hospital tested our methods ability to predict the generation of wound slough in the week that followed each blotting. A total of 70 blots collected from 23 pressure ulcers produced 27 wounds negative for staining and 43 positive. In the negative blots 55.6% were found to have decreased wound slough, while 81.4% with positive staining had either increase or unchanged wound slough generation. These results lead to an odds ratio of positive blotting cases of 9.37 (95% confidence intervals: 2.47–35.5, p = 0.001) for slough formation; suggesting that the changes in wound slough formation can be predicted clinically using a non‐invasive wound blotting method.

Inter-rater and intra-rater reliability outcomes of a rapid bacteria counting system with pressure ulcer samples

OBJECTIVE Evaluating bacterial load in pressure ulcers (PUs) is key to combat infection; therefore, using technologies to measure bacterial count can be particularly useful. A rapid bacteria counting system was recently developed and introduced to the wound care field. However, its reliability was not established. This cross-sectional study aimed to evaluate the inter-rater and intra-rater reliability of bacterial count using this rapid counting system. METHOD We took bacterial swabs from patients with category I or greater PUs to assess inter- and intra-rater reliability. An assessor swabbed the longest axis of the PU once and bacterial counts were measured using a rapid bacteria counting system. To confirm the inter-rater and intra-rater reliability, intraclass correlation coefficients (ICCs) were calculated. RESULTS We took 63 and 57 pairs of bacterial counts from 13 patients with 16 category I or greater PUs to assess inter- and intra-rater reliability, respectively. Overall ICCs [95% confidence intervals (CI)] for the bacterial counts were 0.83 [0.73-0.90, p<0.001, inter-rater reliability, n=63], and 0.89 [0.82-0.94, p< 0.001, intra-rater reliability, n=57]. CONCLUSION A high level of reliability for counting bacterial numbers in PU sites was confirmed. The results should encourage clinicians and researchers to use this type of device for the real-time assessment of wound bacterial bioburden at the patients bedside.

Visualization of Blood Flow in an Undermined Pressure Ulcer Revealed by Sonographic Imaging and Clutter Suppression Post-Processing: A Case Report

The authors report a case of a middle-age man presenting with a category IV pressure ulcer (PU) over the sacrum. Undermining of the PU was assessed with the aid of gray-scale sonography (US), color Doppler US, power Doppler US, and a microvascular imaging technique employing advanced clutter suppression. Clutter suppression post-processing the study allowed for the evaluation of low-velocity microvascular flow in the undermined PU and facilitated the choice of appropriate treatment.

Utility of a three-dimensional wound measurement device in pressure ulcers

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