Hypochlorous Acid Solution as a Transmission Medium for Non-Contact Ultrasound in Colonized Wounds of the Lower Extremity

Background: Both High-Frequency Ultrasound (HFUS) and Low-Frequency Non-Contact Ultrasound (LFNUS) have been explored as treatments for venous leg ulcers (VLU) and share similar efficacy in wound healing. However, HFUS has been established to have a greater incidence of adverse effects than the standard of care (SOC) for wound healing. Of particular interest is LFUS non-contact ultrasound therapy, where a spray aerosol is used as a medium for ultrasound transmission. Recent studies have demonstrated evidence of better wound closure, faster healing time, decreased pain, and increased clearing of exudate and slough with use of LFNUS therapy with a saline liquid agent. Though this modality is relatively new, there is sufficient evidence to warrant further investigation of the efficacy of LFNUS therapy in healing venous leg ulcers.

Purpose: To the authors’ knowledge, few publications exist to date on the use of Hypochlorous Acid (HOCl) in conjunction with LFNUS therapy for specific treatment of lower extremity ulcerations LEUs.

Case History: HOCl is a weak acid that is naturally produced by neutrophils. It leads to bactericidal effects through the activation of intra- and extra- cellular protein kinase pathways. HOCl functions as an effective wound cleanser that demonstrates a number of benefits in wound healing. These include rapid killing of most pathogens in under 30 seconds, a reduction of bioburden in chronic wounds, improved wound healing in presence of comorbidities, and less cytotoxicity than other typical antiseptic agents. Prior studies have demonstrated efficacy of HOCl in reducing bioburden in VLUs, particularly with MRSA and P. Aeruginosa biofilms. In one small study, HOCl in combination with ultrasound treatment was found to lower tissue bioburden in chronic wounds of multiple etiologies. Here we present a case report demonstrating the efficacy of HOCl as a transmission medium with LFNUS therapy on 4 patients with LEUs.