Nitric Oxide Dressings for Traumatic Wounds in Dogs

In the Literature

Marvel SJ, Goldblatt B, MacPhail CM, Zersen KM. The use of a novel nitric oxide wound dressing in acute traumatic wound in dogs. Am J Vet Res. 2024;85(9):ajvr.24.04.0124. doi:10.2460/ajvr.24.04.0124

The Research …

Initial management of traumatic wounds includes clipping surrounding fur, cleaning, flushing, debriding, and applying dressings and bandages until the wound is healthy enough to close. Wound dressings should maintain local antimicrobial activity, stimulate healing, and be nontoxic, nonirritating, and easy to apply. In veterinary patients, dressings that are inexpensive and require less frequent bandage changes and debridement can reduce cost, management time, and patient and pet owner stress. Experimental studies indicate nitric oxide dressings may meet these criteria, but controlled research in dogs and cats is needed.

Research in rodent models has shown nitric oxide dressings can promote angiogenesis, decrease the inflammatory response, increase granulation tissue formation, and hasten wound closure.¹ In rabbits, daily application of nitric oxide probiotic patches improved likelihood of wound healing in ischemic and nonischemic wounds and reduced wound bacterial loads without evidence of toxicity.² Clinical research in humans is in early stages; several hydrogels are in clinical trials, but the effect of nitric oxide should be differentiated from that of the hydrogel carrying agent in controlled studies.³

This prospective case series^a of 24 dogs evaluated effects of a nitric oxide dressing on 30 full-thickness traumatic wounds present for 1 to 4 days. After fur around the wounds was clipped and wounds were cleaned and lavaged, a nitric oxide rehydrated pad or gel was applied, and the wound was covered with a secondary dressing. All dogs were given systemic antimicrobials. Open wound management was used, with bandages and dressings changed a median of every 2 days, until wounds were determined to be ready for surgical closure after a median of 6 days. No local skin reactions to the nitric oxide dressings were noted. Wounds in 5 dogs treated with the gel formulation developed a gray color but healed following closure. Four of 22 dogs available for follow-up experienced complications following closure, including dehiscence, wound drainage, and delayed healing, similar to outcomes in other wound studies.³

Commercially available nitric oxide dressings are not FDA-approved or regulated, and concentrations of nitric oxide released from these dressings are often unverified.¹ High doses of nitric oxide can be toxic to cells, and low doses may have no stimulatory effect on wound blood supply.⁴ Nitric oxide can induce methemoglobinemia, respiratory inflammation, and edema and can react with oxygen to form corrosive nitric and nitrous acids.² Controlled studies are needed to determine optimal doses and timing of application and provide guidance for detection of adverse effects.⁴ For example, delayed application may be recommended to prevent deleterious effects on wound healing because nitric oxide dressings may decrease the inflammatory response.⁴

^a Noxsano supported this study and provided all wound dressings.

… The Takeaways

Key pearls to put into practice:

• Whether nitric oxide dressings have advantages over other wound dressings is unknown.

• Outcomes of wounds treated with nitric oxide dressings are similar to outcomes with other treatments.

• Nitric oxide dressings can cause graying of wound tissues, but this does not appear to affect healing.