How Effective Is Your Wound Cleanser?: An Evaluation Using Bacterial Fluorescence Imaging

Introduction: Wound cleansing to remove surface bacteria is an essential component of wound bed preparation. Most cleansers are cytotoxic, therefore our provincial authority mandates that only normal saline can be used. The province recently conducted an evaluation across six sites of two novel, non-cytotoxic, tissue-compatible wound cleansers: a hypochlorous acid solution, and a modified sodium hypochlorite solution (NaOCl). Our site was uniquely able to assess relative product effectiveness due to our real-time bacterial fluorescence imaging device. 

Methods: Wounds (n=9) were cleansed with normal saline, as per standard practice, after which a fluorescence image was acquired to visualize any concerning levels of bacteria remaining within and around the wound. Wounds were then soaked with hypochlorous acid for at least 6-10 minutes (per manufacturer guidelines), cleansed and re-imaged. Lastly, wounds were sprayed with a modified sodium hypochlorite solution and immediately cleansed and re-imaged. 

Results: Pseudomonas aeruginosa, which fluoresces cyan, was rampant in this patient series. Fluorescence images demonstrated that: (1) Pseudomonas and other bacteria often extend into peri-wound tissues, (2) saline cleansing left behind widespread bioburden in all wounds, and (3) sodium hypochlorite solution was superior to hypochlorous acid in removing Pseudomonas and other bacteria. In all wounds that were cultured (5/8) microbiology confirmed bacterial presence at moderate/heavy loads. Patients reported no product-related irritation or pain.

Conclusions: Our evaluation found that a modified sodium hypochlorite is superior to normal saline in cleansing a wound, and just as fast. Based on these results, we recommend that wounds exhibiting heavy bioburden be cleaned with modified sodium hypochlorite solution. These wounds can be identified from bacterial fluorescence images, without which this real-time evaluation of cleansing effectiveness would not have been possible and regions of concern could not have been specifically targeted.