Use of direct (topical) oxygen delivery at normal atmospheric pressure for treatment of indolent lower extremity ulcers has long been advocated. A typical device involves a soft or semi-rigid plastic sleeve that encapsulates an extremity, is sealed proximally, and filled with oxygen from a high-pressure source or portable concentrator. Advanced options incorporate humidification and a compression cycle to address underlying edemic states. A single use/disposable plastic bag-like device was introduced to treat sacral ulcers but may also be used to cover an extremity ulcer. It is filled with oxygen in the same manner.
Topical oxygen’s effectiveness is considered by many to be presently unproven and health insurers, including Medicare, rule out its reimbursement. In 2020 a randomized, controlled, and double-blind trial (Frykberg RG, et al. Diabetes Care 43: 616-624) reported that topical oxygen plus standard care was superior to standard care alone in healing of chronic diabetic foot ulcers. Given its high-quality design and conduct, some were led to wonder if topical oxygen may eventually become a more accepted and reimbursable therapeutic option. In doing so, it might effectively compete with the practice of HBO therapy for this commonly treated condition, given its low cost, in-home use, and apparent efficacy. A closer look at the study’s design might ease any hyperbaric provider apprehension.
Inclusion criteria involved superficial type ulcers with an average size of 3 cm2. The University of Texas Wound Classification System was employed, although the hyperbaric community is more familiar with the Wagner grading system (in part because it’s a common payor requirement).
If we extrapolate across these two screening tools, most ulcers would be in the order of Wagner Grade 2. HBO therapy is not commonly used and is not reimbursed for this ulcer grade. Next, subjects were required to have moderate to normal distal perfusion with a minimum 0.7 ABI cut off. To account for any falsely elevated ABI’s, secondary screening involved one or more of tcpO2 (> 30 mmHg), skin perfusion pressure (>30 mmHg), toe pressure (> 30 mmHg) or Duplex ultrasound showing below knee biphasic wave forms. We corresponded with the first author and others associated within the study to seek raw tcpO2 data. It would be of interest to learn, as this screening tool is best associated with hyperbaric case management of DFU referrals. We were advised that very few of the participating centers had used TCOM’s. We acknowledged this but continued to request the data. We felt it would be of interest to determine if values may have been high enough to obviate any indication for HBO therapy. Nothing was forthcoming at the time of this writing. Finally, patients with major comorbid diseases were excluded.
As vascular screening inclusion criteria would suggest reasonably good healing potential, Dr. Caroline Fife posited that the question this study appeared to be asking was whether minor DFU’s would heal faster with topical oxygen, rather than healing vs. no healing. She added that this should be considered a non-generalizable study of otherwise healthy patients with superficial ulcers.
DFU’s treated in this study were not, therefore, of a grade extensive enough to prompt HBO referral. There is also nothing in the study to suggest topical oxygen is beneficial for these higher ulcer grades and in patients with less well perfused tissues commonly associated with sicker patients, some of whom are commonly suffering co-morbidities. These latter carefully selected DFU’s continue to remain within the purview of the hyperbaric practitioner while topical oxygen was reported to accelerate healing of adequately perfused superficial ulcers.