Is Your Wound Bioburdened? Case 6

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CASE & INITIAL EXAMINATION

• Generally healthy male with a below the knee amputation of the right leg. No history of diabetes.
• Pressure injury was the result of an ill-fitting prosthetic. Had been receiving treatment for several weeks.
• Evidence of callus formation was present with devitalized tissue around the wound edge.

CLINICAL DECISION

• Fluorescence imaging (MolecuLightDX) displayed bright yellow and blush red fluorescence in the peri-wound. Yellow and blush red fluorescence indicated to the physician the presence of elevated bacterial loads (>10⁴ CFU/g) slightly below the surface of the skin.
• Sharp debridement was performed, focusing on the yellow fluorescing regions in the callused wound edge. Debridement was performed under violet light illumination.
• As the tissue and bioburden was debrided away, more blush and red fluorescence was observed from under the callused tissue.
• Sharp debridement was done up to the point of viable tissue. The wound was cleansed with hypochlorous acid. Red/blush fluorescence still remained in the peri-wound.
• Povidone-iodine was prescribed to be applied specifically to the peri-wound, but not in the wound bed.

LEARNING OPPORTUNITY

• Yellow fluorescence signals were observed during fluorescence imaging. This color signal differs slightly from the red and cyan fluorescence which are typically associated with elevated bacterial loads.
• Fluorescence imaging can detect fluorescence signals up to ~1mm under the skin.
• Since the device filters out yellow wavelengths of light, yellow signals in the fluorescence image can only occur when red (elevated bacterial loads) and green (skin, callus) fluorescence signals mix.
• Thus, yellow fluorescence is also associated with elevated bacterial loads present just underneath the skin or callus (up to 1mm deep), and clinicians should be aware of this when interpreting the images.
• Debridement revealed more red fluorescence and less yellow as the tissue was removed. This confirmed the persistence of subsurface bacterial loads.

OUTCOME

• Having monitored this wound weekly with fluorescence imaging, the amount of callus and the bioburden (red/yellow fluorescence) had already been greatly reduced. The wound had been getting smaller.
• Fluorescence-guided debridement removed the callus tissue and red/yellow fluorescing bioburdened tissue. With the addition of povidone-iodine to the peri-wound, we suspected that we’d be able to completely reduce the bioburden in the coming weeks.
• After 16 weeks, this wound did go on to heal completely.

CLINICAL PERSPECTIVE

• Yellow fluorescence still indicates the presence of elevated bacterial loads, just under the surface of the skin. These areas require attention, just like areas of red and cyan fluorescence which indicate the presence of elevated bacterial loads.
• Oftentimes, red, blush or yellow fluorescence will occur in areas of callus or intact skin in the peri-wound. Debridement of intact skin may not be possible or clinically advisable for a given patient. In our clinic, using topical povidone-iodine in these regions has demonstrated positive results in decreasing the peri-wound bioburden when we re-image at follow-up visits.
• By monitoring the wound week to week, we’ve seen dramatic decreases in the red/yellow fluorescing bioburden and decreases in wound size with this combination of aggressive debridement/hygiene and topical application of antiseptic to the peri-wound (when indicated).
 
Dr. Ruotsi is the Medical Director of Saratoga Hospital Center for Wound Healing and Hyperbaric Medicine in Saratoga Springs, NY.