Thomas Serena, principal investigator of the recently completed Natrox clinical trial—a randomised controlled multicentre trial examining the effect of topical oxygen wound therapy on the healing rate of chronic diabetic foot ulcers—provides an overview of the pros and cons of topical oxygen therapy. He highlights that a “a growing body of evidence” favours this relatively new therapy option, and outlines the potential mechanism by which topical oxygen therapy helps heal diabetic foot ulcers.
Is there a role for topical oxygen therapy (TOT) in the armamentarium of the wound care specialist? A growing body of evidence suggests that topical oxygen promotes healing in diabetic foot ulcers (DFU). There are two published randomised controlled clinical trials and one just completed that have demonstrated a benefit of TOT compared to standard of care in healing DFUs. The most recent trial was designed to treat patients that qualify for advanced therapy. The DFUs had to have failed to heal by 40% in four weeks of good wound care including debridement, off-loading, appropriate moisture balance, and reduction in bacterial burden.
The proposed mechanisms of action for TOT included antimicrobial effects, increased production of cellular energy, stimulation of angiogenesis, increased collagen synthesis, and promotion of epithelialisation. Topical oxygen increases the oxygen tension in the wound, which in turn enhances the bacterial killing ability of leukocytes. The increased oxygen available to cells increases the production of the energy-carrying molecule adenosine triphosphate (ATP). One study revealed that topical oxygen increased the pro-angiogenic growth factor, VEGF (vascular endothelial growth factor). Collagen synthesis has several oxygen dependent steps and studies have shown that wounds that heal in a higher oxygen environment have greater tensile strength. It has long been reported that epithelial cells respond favourably to high levels of oxygen.
One of the concerns voiced about TOT is that it might replace hyperbaric oxygen therapy (HBOT). This is a myth. The indications for use and the mechanisms of action differ between the two modalities. They are complementary, not competitive. In addition, HBOT requires specialised training and expensive equipment. Not all wound centres across the world will have access to this technology. In contrast, TOT is portable, and can be used to deliver oxygen in a wide variety of care settings.
Thomas Serena is the founder and medical director of The SerenaGroup, a family of wound, hyperbaric, and research companies.
Disclosures: Serena conducted the recent Natrox clinical trial, NOW.T.
