Point-Counterpoint: HBOT: Is It Worthwhile For DFUs?
Patients are incapable of supersaturating the hemoglobin in their blood, even when breathing 100% oxygen. Under hyperbaric conditions, however, the plasma that normally has an insignificant amount of dissolved oxygen is now saturated with enough oxygen to support the body’s metabolic needs even in the absence of all hemoglobin.32 For a patient who has diabetes and concomitant atherosclerosis with microvascular disease, the use of HBOT permits oxygen to flow past areas of critical stenosis and reach areas of previously ischemic tissue, allowing for the natural wound healing process to resume.
In 2003, the Centers for Medicare and Medicaid Services (CMS) determined reimbursement policies for HBOT with regard to diabetic foot ulcers based on a single, pivotal randomized controlled trial (RCT) that assessed hospitalized patients with serious foot infections (e.g., Wagner Grade 3 and 4 DFUs).4 This study showed patients benefited from HBOT when clinicians used it in conjunction with aggressive surgical management of the wound, offloading of the foot, aggressive management of diabetes using intravenous insulin, culture-driven antibiotic therapy to eradicate infection, and aggressive revascularization of patients with peripheral arterial disease.
While the CMS decision has been critical with regard to the financial viability of using HBOT for diabetic foot ulcers, it has created discordance between what the science has shown to work and what the government is willing to pay to treat. The CMS criteria state that any patients who have a diabetic foot wound can receive HBOT if they have a Wagner 3 or greater stage ulcer and have not had any measurable signs of healing for 30 days of standard wound therapy.30 The original study focused on the acute dysvascular foot while CMS indications focus on outpatient, chronic diabetic foot ulcers. This disconnect has been the source of consternation for clinicians who feel like they are forcing a square peg in a round hole when treating their patients.
A Closer Look At Recent Controversies In The Literature On HBOT
A recent retrospective review concluded that HBOT did not improve the likelihood that a wound would heal and did not decrease the chance of an amputation.34 The authors analyzed data from a large national database in the hopes of proving that HBOT provided a significant reduction in amputations and improved healing rates. What they found was a surprise to say the least and researchers have directed many criticisms at these authors for their methodology and conclusions.35-39
For me, however, the takeaway lesson was that this effectiveness study showed that HBOT, as practiced in a real-world, for-profit setting, did not reflect the results of prior efficacy studies that used much more rigid inclusion and exclusion criteria.
While the criteria listed in the CMS guidelines for standard wound therapy mirror best practice recommendations, it depends on each individual practitioner to apply the highest amount of rigor when addressing them. The bigger issue, though, is the shifting interpretation of the Wagner scale to the stable outpatient diabetic foot ulcer.
Strauss provides an informative history of the now all-important Wagner scale and its modifications by the hyperbaric community over the years.40 As Strauss states, “the Grade III wound as Wagner classified it (i.e., systemic sepsis caused by a deep abscess and/or osteomyelitis and requiring in-hospital management including immediate debridement, IV antibiotics, and medical/diabetic management) is far different than the criteria used for outpatient HBO management of (diabetic foot wounds).”