Hypochlorous Acid in Pediatric Wound Management: From Cleansing to Healing Wounds

Introduction

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.

Case Reports

Case 1: pressure injury. A 15-year-old male patient was admitted to the pediatric intensive care unit with a sacral pressure injury and a history of multiple comorbidities, including tuberous sclerosis, congenital heart disease, neurodevelopmental delay, and multiple benign tumors. His neurodevelopmental status was significant for autism, aggressive behavior, and poor communication and social interactions. His hospital admission was precipitated by a worsening respiratory status due to smooth muscle overgrowth in his lung, leading to pneumonia. The patient was not very mobile at home; his immobility worsened in the hospital.

The patient’s wound was partially covered with slough, the edges were slightly thickened, and granulation tissue growth was stagnant (Figure 1A). The wound was found to be colonized by Enterococcus faecalis, likely due to the presence of stool. The patient was not incontinent, but he had difficulty verbalizing when he had a bowel movement.

The patient’s parents were resistant to trying new products because he had multiple allergies, including allergies to honey and sulfadiazine; he had experienced multiple bouts of irritant contact dermatitis related to past dressings. Staff found it difficult to keep the wound clean due to its location. Hypochlorous acid solution compresses using well-saturated gauze were provided twice a day or more if necessary (eg, if the area was contaminated with stool) for 15 minutes, and HOCl solution was poured into a spray bottle and sprayed on the wound. The wound then was patted dry and a nonalcohol liquid polymer applied to periwound tissue along with an atraumatic silicone dressing (Mepilex Border, Mölnlycke Health Care). The patient was very sensitive to mechanical debridement due to his condition, so this was avoided. Over a 1-week period, the slough was mostly removed and healthy granulation tissue started to fill in the wound bed. Figure 1B shows the pressure injury after 10 days. The patient was discharged home after 3 weeks where the parents continued the HOCl solution regimen twice a day. Figure 1C shows the remarkable improvement noted in wound healing at 6 weeks.

Case 2: deep tissue injury (DTI). A 2-day-old, full-term neonate developed hypoxemic respiratory failure secondary to meconium aspiration and was placed on venoarterial extracorporeal membrane oxygenation(ECMO). While on ECMO, the patient was continuously anticoagulated. Head and neck movement was limited due to the challenging cannula positioning. On day 5, a DTI of his left ear was noted (Figure 2A); on day 7, multiple areas of superficial skin breakdown appeared (Figure 2B). Gauze-soaked HOCl solution compresses were applied to the ear every 6 hours for 5 minutes. The skin then was covered with a thin layer of Bactroban ointment and a soft silicone-based foam (Mepilex Lite, Mölnlycke Health Care). Skin breakdown remained superficial, no infection occurred, and in 9 days the skin was mostly healed (Figure 2C).

Case 3: multiple colonized erosions. A 26-week neonate developed multiple skin lesions over the first 3 days of life. His preterm birth was due to maternal chorioamnionitis, clinical sepsis, and skin culture positive for Staphylococcus epidermidis. The patient was hypotensive and mechanically ventilated; treatment included use of a high-frequency oscillator, inhaled nitric oxide, and systemic antibiotics. On day 4, multiple superficial erosions, covered by slough, were noted on his back and sides. Several areas had serosanguinous exudate (Figure 3A); a few progressed to deeper wounds, covered by thicker slough. One wound on his midback was especially challenging: the wound was round, approximately 2 cm in diameter, and presented as would a pressure injury, although no round-profiled equipment was under the baby. This wound was deeper than the other lesions on the baby, with a hemorrhagic wound bed and thicker edges. Given the extreme immaturity and critical status of this patient, skin care needed to be simple, effective, yet nontoxic, not painful, nonirritating, and gentle on application to skin. Pure HOCl solution was applied using a spray bottle over the entire area and allowed to remain on the skin for up to 5 minutes. Gauze impregnated with HOCl solution was placed on the areas of slough and the (questionable) pressure injury during this time, and Mepilex Lite was used to cover the affected area. This protocol was provided every 6 hours in the warmed, humidified isolette to ensure the infant remained normothermic. Slough was eliminated almost completely in 4 days (Figure 3B), and new granulation tissue was found to be growing in the deeper round wound. Healthy epithelial tissue started to grow (Figure 3C), and the patient’s skin was completely healed by 2 weeks

Conclusion

Our experience with multiple children of various ages, including premature neonates, adds to the growing literature on the successful and safe management of various neonatal and pediatric wounds using a pure HOCl solution. We did not observe any pain or discomfort with HOCl acid application for our entire cohort of 15 patients, including the patients described here. Further studies involving a larger cohort would be recommended to definitively establish the efficacy of HOCl in pediatric/neonatal wound care.

Pearls for Practice is made possible through the support of Urgo Medical, Fort Worth, TX (www.urgomedical.com). The opinions and statements of the clinicians providing Pearls for Practice are specific to the respective authors and not necessarily those of Urgo Medical, Wound Management & Prevention, or HMP Global. This article was not subject to the Wound Management & Prevention peer-review process.