Roundtable Insights On Hyperbaric Oxygen Therapy

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Weighing In On Topical HBO

Q: Is there any good proof that extremity HBO chambers are effective?

A: All of the panelists agree that this is a highly controversial subject and emphasize that HBO extremity chambers provide an entirely different type of therapy than the monoplace chambers that provide systemic HBO.

Dr. Kominsky says the buzz on extremity HBO chambers tends to be cyclical. He recalls that approximately 15 years ago, several companies touted the benefits and safety profile of extremity HBO chambers. Around the same time, Dr. Kominsky notes there were several published reports that said the units were ineffective because they could not provide the same amount of atmospheric pressure as the full body units. He also points out that the same reports said the units were dangerous and prone to exploding.

Several new companies are again promoting the benefits of employing extremity HBO chambers, but Dr. Kominsky says he doesn’t have any experience in using these devices.

Dr. Sage has used extremity HBO chambers on two occasions with successful healing in renal transplant patients who had stubborn ulcers but otherwise adequate vascular perfusion. However, he cautions that he’s not sure whether it was the topical HBO that made the difference or whether the extra care involved motivated the patients to offload more effectively and thus facilitated healing.

Dr. Armstrong has doubts about the extremity chambers. He says systemic HBO, theoretically, works by supersaturating hemoglobin and then plasma with oxygen at greater than one atmosphere absolute. “Unless one’s legs have evolved to the point where they have sprouted gills, that cannot be the mechanism of action of topical HBO,” maintains Dr. Armstrong.

Drs. Brill and Sage add that they aren’t aware of any definitive, controlled studies that demonstrate the efficacy of topical HBO.

Roundtable Insights On Hyperbaric Oxygen Therapy
Clinical Editor: Lawrence Karlock, DPM

However, Dr. Brill says there is compelling evidence that HBO does have a beneficial effect. Last year. Medicare published a decision memorandum regarding the coverage of HBO and Dr. Brill says this document provides a good synopsis of the HBO studies that have been conducted so far. However, he does caution that there are major flaws such as comparability of patients, treatment bias and the inability to adequately blind the studies.
There are numerous anecdotal and retrospective studies that support using hyperbaric oxygen in problem wounds, according to Dr. Sage. He says these studies are nicely summarized on, the Web site of the American College of Hyperbaric Medicine.
Dr. Armstrong says he is not certain if there are any good, evidence-based or even anecdotally-based protocols that would drive one to use or not use HBO. However, he does cite a few intriguing studies. Kalani, et. al., from the Karolinska Institute in Sweden, presented a small randomized, controlled trial of 38 patients. Dr. Armstrong says this study suggested that using 40 to 60 dives of HBO per patient appeared to accelerate healing and lower the prevalence of amputations in a three-year follow-up.
According to Dr. Sage, Faglia, et. al., may have done the best study to date of using HBO in Wagner Grade III ulcers with their 1996 study published in Diabetes Care. The study was comprised of 35 patients who had standard wound care and 33 patients who received HBO. Dr. Sage says the amputation rate was 100 percent in the standard care group whereas the HBO group had a 25 percent amputation rate.
However, Dr. Armstrong says studies, such as the one by Faglia, et. al., have been “fatally flawed” in one way or another. Dr. Armstrong points out that, in Faglia’s study, far more people in the HBO group received lower-extremity bypasses than in the non-HBO group, rendering the data less than helpful.
While the study may be flawed, Dr. Sage says it was considered to be “pivotal” in the recent decision by the CMS to reimburse hyperbaric oxygen therapy for diabetic ulcers, according to the American College of Hyperbaric Medicine.
While Dr. Armstrong notes there is a physiologic rationale for why HBO should work, he says “translating that into viable indications has been problematic for many.”

Q: What are the current reimbursement issues in regard to insurance companies and Medicare paying for this modality?
HBO is a reimbursable procedure under Medicare, according to Drs. Kominsky and Sage. (Editor’s Note: For further info, see “CMS Expands Coverage Of HBO To Diabetic Foot Ulcers,” News & Trends, April issue.) Dr. Kominsky says HBO is also reimbursable under many of the managed care plans as well. Dr. Kominsky does caution that pre-authorization is necessary in some instances. He also points out that some third-party carriers limit the number of dives. In these cases, Dr. Kominsky says you may need to provide photo documentation in order to continue using the therapy to wound closure.
Dr. Armstrong has heard that recent Medicare findings are very promising in terms of funding this type of therapy. However, he does express concern that when facilities invest in the chambers, there may be an accompanying pressure to use the therapy on patients who may or may not have the appropriate indications.
“Frequently, the decision by an HBO specialist is ‘Let’s give it a try and see how it works,’” explains Dr. Armstrong. “Unfortunately, giving HBO a try is a bit more expensive than modifying an offloading modality or using a different dressing. I will admit this is changing, but it’s not changing fast enough or in enough centers to satisfy many skeptical physicians.”

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