An antimicrobial wound cleanser must be noncytotoxic, nontoxic if absorbed percutaneously, effective in various forms, and painless on application.1 A cleansing solution containing the antimicrobial preservative hypochlorous acid (HOCl; Vashe Wound Solution, Urgo Medical) has been added to the wound cleansing regimen in our neonatal and pediatric care practice.
Hypochlorous acid is a substance endogenous in all mammals and is effective against a broad range of microorganisms.2 Neutrophils, eosinophils, mononuclear phagocytes, and B lymphocytes produce HOCl in response to injury and infection through the mitochondrial membrane-bound enzyme nicotinamide adenine dinucleotide phosphate oxidase.3,4
The pH of HOCl meant for use in wound care is extremely critical, both for the purity of the compound and for its ability to achieve clinical efficacy in wound healing. Pure HOCl has been proven to have maximal antimicrobial preservative properties that exceed that of the hypochlorite species largely found in the Dakin’s solution and in products that have a pH higher than approximately 5.5.5 Hypochlorous acid exists as the desirable neutral, undissociated, and antimicrobial preservative compound at a pH range of approximately 3 to 5.5; formulations with a higher pH inevitably become contaminated with sodium hypochlorite, because the HOCl begins to break down significantly to the hypochlorite anion at a pH higher than 5 to 6.5-7 The hypochlorite anion is strongly associated with cytotoxic properties,5,8,9 and its use in wound care (primarily as Dakin’s solution or, to downregulate its cytotoxicity, as quarter-strength Dakin’s solution) is declining as better choices, such as pure HOCl-based wound management solutions, have become available. The pH of Vashe is kept at a focused and tight range to avoid contamination with any amount of the hypochlorite anion. Research also has shown that this slightly acidic pH range of Vashe is similar to the acid mantle of healthy skin, in addition to being associated with positive outcomes in wound healing.10,11
Hypochlorous acid also destroys viruses by forming chloramines and nitrogen-centered radicals, resulting in single- and double-stranded DNA breaks, thus rendering the nucleic acid of the DNA nonfunctional and a virus harmless.12
Hypochlorous acid is widely used in multiple medical applications, including in dental treatment as a mouth rinse and in ophthalmology as treatment for blepharitis.2 In evidence-based wound care,13,14 HOCl also has been utilized to eliminate biofilm in chronic wounds,15,16 as an effective instillation medium for negative pressure therapy17 and ultrasound therapy,18 and in general as a cleanser for wounds that contain debris or microbes.16,19 Because of its safety profile, HOCl also has been found to be successful for use as a hand sanitizer and a disinfectant for surfaces and equipment.2 Animal studies2 have shown it to be safe if ingested as well as in ocular exposure, and several commercial eye care products containing HOCl are available in the United States. It is available in multiple commercial preparations for various modes of application, including as a solution, aerosolized droplets, or compounded gel.2
A review of evidence suggests that the intact, undissociated pure HOCl-based product has an excellent safety profile in wound care.5
The formulation (Vashe) specifically indicated for wound care described herein has been reported as safe and efficacious in previous case reports on preterm neonates.20 The following 3 cases represent a sampling of a larger cohort of 15 pediatric and neonatal patients who, when HOCl was added to their wound care regimen, experienced successful wound healing.