Wound Assessment Paradigm Shift: A 350-Patient Multi-Site Clinical Trial Incorporating Bacterial Fluorescence Imaging into Standard of Care

Objective: Moderate-to-heavy bacterial loads delay healing and can lead to infection; therefore, clinical evaluation of signs and symptoms (CSS) of the bacterial-infection continuum is imperative to wound assessment. However, patients with heavily colonized and infected wounds are often asymptomatic, leading to poor diagnostic accuracy. Point-of-care fluorescence imaging (FL) rapidly provides information on the presence and location of bacteria. This clinical trial aimed to evaluate diagnostic accuracy when fluorescence imaging was used in combination with CSS for identifying wounds with moderate-to-heavy bacterial loads (>104 CFU/g).

Methods: A total of 350 chronic wounds patients (138 DFU/106 VLU/22 PU/60 SSI/24 Other) were assessed for CSS based on International Wound Infection Institute guidelines by 20 clinicians across 14 trial sites. Only then were fluorescence images of the wound acquired and bacterial fluorescence (red or cyan) determined to be present or absent. Wounds were biopsied to confirm true bacterial load.

Results: The sensitivity of CSS assessment alone (15%) was very poor across all study sites, wound types, and bacterial loads; multiple wounds with loads of 109 CFU/g were asymptomatic. FL-imaging in combination with CSS led to a fourfold increase in sensitivity (61%, p<0.001) for detecting moderate-to-heavy loads, and a 45% increase in the number of appropriately identified wounds. This was consistent across all wound types, sizes, durations, study sites. Specificity of FL images was high (89%) and diagnostic odds ratio of CSS+FL was 8.28 vs. 2.67 for CSS alone, a 3.1-fold increase in assessment effectiveness.

Conclusions: Proper placement of wounds on the bacteria-infection continuum enables appropriate wound management, preventing bacterial escalation and association complications. Incorporation of FL information led to immediate, appropriate, evidence-based patient care in the 45% of wounds that were FL-positive but CSS-negative. These findings, consistent across all study clinicians and sites, support incorporation of FL imaging into standard of care best practices worldwide.