Top Ten Things You Need to Know About HBOT #2: The Difference Between Topical Oxygenation Therapy and HBOT

In the ninth article in a series, this review article will discuss and give updates on the top ten things we need to know about hyperbaric oxygen therapy (HBOT).
 

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Did you know that topical oxygen therapy is not hyperbaric oxygen therapy?

It is well known that oxygen is vital for wound healing.¹ Throughout the years, attempts have been made to address wound hypoxia and deliver adequate amounts of oxygen to both the wound and peri-wound. Some have been more successful than others. Today we are discussing difference between topical oxygenation therapy (TOT) and hyperbaric oxygen therapy.
 
TOT is an adjunctive, non-invasive modality that can be used in the management of chronic wounds. It is not to be confused with HBOT, which requires the patient to be placed inside a pressurized hyperbaric chamber, where oxygen is delivered systemically and reaches the wound through the plasma. As the name suggests, TOT is delivered topically, but despite the stark contrasts with HBOT, some clinicians have erroneously referred to this treatment modality as “topical hyperbaric oxygen wound therapy” or “topical hyperbaric oxygen,” leading to misconceptions and confusion.
 
TOT is delivered via a variety of applicators available on the market. These range from large high-flow oxygen systems to small oxygen delivery systems.² They allow for direct, topical application of oxygen to the wound site and do not require diving at an HBO therapy center, as the delivery of the oxygen is topical and not systemic. Usually, the oxygen delivery via TOT devices is done through cycles and is managed at home by the patient, which is another key difference between TOT and HBOT and can be viewed by many as an advantage.
 
In terms of research and literature, HBOT is well studied and there are many publications regarding its efficacy in wound healing. Boerema, regarded as the father of hyperbaric medicine, published the first clinical paper on HBOT in 1956 at the University of Amsterdam.³ The first paper on TOT was published on 1962 in The Lancet by Fischer, but comparatively, the research efforts geared towards this specific modality have been much less than that of HBOT. While some studies support the fact that TOT improves healing⁴, other studies also indicate that wounds treated with TOT heal slower than those who receive HBOT.⁵ Despite there being some evidence-based guidance as to the use of TOT for wound healing, the body of work is still lacking.

Additionally, for many years, the efficacy of the use of TOT for wound healing was largely anecdotal. This reinforces the fact that TOT is a modality that has yet to be further studied and a consensus reached regarding its efficacy.

However, we are not suggesting that TOT is to be completely dismissed but rather to consider that TOT is not to be used as a single modality in the treatment of chronic wounds but rather as an adjunct to optimal wound care. 2 Studies have shown that adding TOT to standard of care hastens wound closure in diabetic foot ulcers that are hard to heal.⁶ In fact, studies show that TOT as an adjunct to standard of care can increase the likelihood of healing by four and a half times.⁷
 
TOT is a completely different modality than hyperbaric oxygen therapy and they both should not be confused. There is no alternative to hyperbaric oxygen therapy. TOT should be considered as another adjunct advanced wound care modality that could be utilized in the management of hard to heal wounds. It is important to point out that the clinician must be careful to select the appropriate patient and the appropriate wound for TOT vs HBOT. The ultimate goal is a good patient outcome combined with patient safety and for this reason, TOT can be a safe and valid alternative for patients in which HBOT is not a feasible modality. At this time, TOT is not approved for reimbursement by most insurances.
 
Denise Nemeth is a second-year medical student at the University of the Incarnate Word School of Osteopathic Medicine in San Antonio, TX. Formerly a general and vascular surgery PA in a rural community, Ms. Nemeth aspires to become a general surgeon. She is a certified wound specialist with the American Board of Wound Management. Her interests include rural health, wound healing, colorectal surgery, and minimally invasive surgery.
 
Jayesh B. Shah is the Immediate Past President of the American College of Hyperbaric Medicine and serves as medical director for two wound centers based in San Antonio, TX. In addition, he is president of South Texas Wound Associates, San Antonio. He is also the Past President of both the American Association of Physicians of Indian Origin and the Bexar County Medical Society and Current Board of Trustees of the Texas Medical Association.   

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References
1. Castilla DM, Liu ZJ, Velazquez OC. Oxygen: Implications for wound healing. Adv Wound Care (New Rochelle). 2012;1(6):225-230. doi: 10.1089/wound.2011.0319 [pii].
2. Oropallo A, Andersen CA. Topical oxygen. In: StatPearls. Treasure Island (FL): StatPearls Publishing LLC; 2022. NBK574579 [bookaccession].
3. Hajhosseini B, Kuehlmann BA, Bonham CA, Kamperman KJ, Gurtner GC. Hyperbaric oxygen therapy: Descriptive review of the technology and current application in chronic wounds. Plast Reconstr Surg Glob Open. 2020;8(9):e3136. doi: 10.1097/GOX.0000000000003136 [doi].
4. Niederauer MQ, Michalek JE, Liu Q, Papas KK, Lavery LA, Armstrong DG. Continuous diffusion of oxygen improves diabetic foot ulcer healing when compared with a placebo control: A randomised, double-blind, multicentre study. J Wound Care. 2018;27:S30-S45. https://doi.org/10.12968/jowc.2018.27.Sup9.S30. doi: 10.12968/jowc.2018.27.Sup9.S30.
5. Winfield B.  Topical oxygen and hyperbaric oxygen therapy use and healing rates in diabetic foot ulcers. Wounds. 2014(5):E39-E47.
6. Serena TE, Bullock NM, Cole W, et al. Topical oxygen therapy in the treatment of diabetic foot ulcers: A multicentre, open, randomised controlled clinical trial. J Wound Care. 2021;30(Sup5):S7-S14. doi: 10.12968/jowc.2021.30.Sup5.S7 [doi].
7. Frykberg RG, Franks PJ, Edmonds M, et al. A multinational, multicenter, randomized, double-blinded, placebo-controlled trial to evaluate the efficacy of cyclical topical wound oxygen (TWO₂) therapy in the treatment of chronic diabetic foot ulcers: The TWO₂ study. Diabetes Care. 2020;43(3):616-624. doi: 10.2337/dc19-0476 [doi].