By Temple University School of Podiatric Medicine Journal Review Club

Editor's note: This post is part of the Temple University School of Podiatric Medicine (TUSPM) journal review club blog series. In each blog post, a TUSPM student will review a journal article relevant to wound management and related topics and provide their evaluation of the clinical research therein.

Article: Use of a Bacterial Fluorescence Imaging Device: Wound Measurement, Bacterial Detection and Targeted Debridement

Authors: Raizman R, Dunham D, Lindvere-Teene L, et al.

Journal: J Wound Care. 2019;28(12):824-834

Reviewed by: Dhara Doshi, class of 2021, Temple University School of Podiatric Medicine

Introduction

The treatment of wounds has advanced significantly over the years and has involved a variety of therapy options, but the percentage of wounds that heal after 12 weeks remains at a mere 40%. One idea to improve wound healing is to improve diagnostic imaging of wounds, similar to the technological advances seen in many other specialties. Wound healing is costly, especially given that many wounds are hard to heal or there is difficulty in identifying the best course of treatment for the wound. If the current wound healing treatments show minimal improvement in four weeks and there are still thousands of bacteria-forming units on the wound, the clinician should re-evaluate the therapies being utilized and consider a change in treatment.

A fluorescent imaging device is an accurate tool used to identify areas on the wound with pathological bacterial loads and to aid in measuring wound areas in real time. Visit-to-visit, point-of-care analysis is becoming more common in wound care practices across the country. The fluorescent imaging device uses a non-invasive, contrast-free violet light to identify the fluorescent bacteria that emit red and cyan colors on the imaging software while at the same time providing an accurate measurement of wound area. Once the increased bacterial colonies are identified, targeted debridement can occur to decrease bacterial quantities and improve wound granulation.

Wound Assessment, Treatment and Follow-Up

Methods

In this study, five clinicians measured images taken by the fluorescent imaging device for accuracy and intrarater and interrater reliability. The Fitzpatrick scale was used to standardize skin tones because the melanin in the patient’s skin could affect cyan fluorescence. Of the 50 wounds analyzed, 36 were diabetic foot ulcers, four were venous leg ulcers, three were arterial leg ulcers, and seven were wounds with unknown infections. To record the images of the wounds, measurement calibration stickers were placed near the wound, and measurements were recorded under normal light.

The next set of images was taken with the lights off, and violet light was used to capture the bacterial load on and around the wound area. A positive test result was noted if the wounds fluoresced red, pink, blush, or cyan, and then those areas were swabbed to determine the bacteria species. After noting where the wounds fluoresced, the clinicians determined whether they should sharply debride the wound and its margins, and consecutive images were taken to see whether there was an improvement in the bacterial load. Of note, the most fluorescence was frequently observed in the periwound tissue rather than the wound bed itself.

Results

The Levine sampling technique was used in the study, but the results show an underrepresentation of the bacterial load in the wounds. However, this technique did reveal the presence of bacteria in the wound beds. Because the study identified the areas of high bacterial loads, the study investigators used fluorescence imaging to assist with debridement of wounds. Although fluorescence initially helped with targeted debridement, not all the infected tissue was removed because the imaging software can penetrate only to a depth of 1.5 mm, and diabetic foot ulcers with heavily calloused skin are thicker than 1.5 mm.

Conclusion

This study discussed the benefits of using an imaging device to improve wound treatment by providing accurate wound care measurements, as opposed to the ruler method, which lacks interrater reliability and often overestimates the area of the wound. Also, digital measurement offers an easier way to input documentation into the system and eliminates some subjective assessments that offer low sensitivity for bacteria and infection. Using this or any new imaging device to measure wounds and detect bacteria for targeted debridement can improve the administration of wound therapies and aid in dressing and advanced therapy applications.

About The Author

Dhara Doshi is a third-year podiatric medical student at Temple University School of Podiatric Medicine (TUSPM) in Philadelphia, Pennsylvania. She graduated from SUNY Stony Brook University in 2012 with a Bachelor of Science in Psychology and a minor in Biology. She entered TUSPM in 2017 and became involved within her class. She is Curriculum Representative for her student council for the past three years. She is President of the Community Service Club, where she volunteers at the local churches providing awareness of the podiatry field and other local events. She is also the academic chair for the TUPSM Wound Care Club. Dr. James McGuire is the director of the Leonard S. Abrams Center for Advanced Wound Healing and an associate professor of the Department of Podiatric Medicine and Orthopedics at the Temple University School of Podiatric Medicine in Philadelphia.