SAN DIEGO – Hyperbaric oxygen therapy, a mainstay of wound care, has a long and controversial history as a treatment for diabetic foot ulcers. Conflicting studies have spawned plenty of debate, and the most recent Cochrane Library review of existing research didn’t shed much light on the value of the treatment because the evidence was weak (Cochrane Database Syst Rev. 2015 Jun 24;[6]:CD004123).
But William H. Tettelbach, MD, a wound care specialist, told an audience at the annual scientific sessions of the American Diabetic Association that hyperbaric treatments are worth a try in certain cases. And he brought evidence to prove it – a 2015 report he coauthored that reviewed studies and offered clinical practice guidelines for hyperbaric oxygen therapy for the treatment of diabetic foot ulcers (DFUs) (Undersea Hyperb Med. 2015 May-Jun;42[3]:205-47).
Dr. Bill Tettelbach
In an interview, Dr. Tettelbach discussed ideal candidates for the treatment and offered clinical advice to endocrinologists.
Question: What did your review of research tell you about the value of hyperbaric oxygen treatment for DFUs?
Answer: We came to the same conclusion that most of the papers have indicated over the years: Hyperbaric oxygen is effective and attains goals such as reducing rates of amputation in a select population of diabetic ulcer patients.
Patients who have Wagner grade 3 or greater ulcers or admitted for surgery due to a septic diabetic foot benefit from an evaluation by a hyperbaric medicine–trained physician and treatment when indicated. There is evidence and years of clinical experience indicating that these patients benefit and have improved outcomes when evaluated and treated appropriately with hyperbaric oxygen therapy.
In the United States, hyperbaric oxygen therapy is not indicated in Wagner grade 2, 1 or 0 diabetic foot ulcers, the ulcers that involve soft tissue but not deep structure like bone.
Q: Why has there been so much controversy over the value of this treatment?
A: In the past, there have been problems with commercial outpatient wound centers that are heavily driven by profits. Financial margins in wound care clinics can be tight, and the need to remain profitable has at times resulted in patients being treated inappropriately with hyperbaric oxygen therapy (Adv Skin Wound Care. 2017 Apr;30[4]:181-90).
Q: Why does hyperbaric oxygen treatment work in some cases?
A: When you place a patient in a hyperbaric chamber where they breathe 100% oxygen under pressure, you increase the percentage of oxygen in the blood. At such a high percentage, oxygen saturates the plasma versus just being carried by red blood cells, thereby allowing the oxygen to penetrate farther into hypoxic tissues. By increasing the oxygen, you have the ability to make the environment unfavorable for rapid proliferation of anaerobic or microaerophilic bacteria that do not survive a highly oxygen-rich environment. Increasing tissue oxygen tension to 30 mm Hg or greater increases the macrophages’ ability to have an oxidative burst needed to kill bacteria. Furthermore, there are antibiotics that require certain levels of oxygen for transport across the bacterial cell wall.
Q: What should physicians understand about hyperbaric oxygen therapy for DFUs?
A: Overall, hyperbaric practitioners need to be more selective in identifying and treating patients according to what the evidence supports. Poorly designed trials with misleading results should not drive medical decisions. We should revisit diabetic foot ulcers through well-thought-out studies that target those who would benefit as suggested by current evidence. Prior trials have been heavily weighted with Wagner grade 1 and 2 candidates or ischemic diabetic ulcers that are not revascularized. These are biased toward poor outcomes since the current evidence does not strongly support treating these types of individuals with adjunctive hyperbaric oxygen therapy (Ont Health Technol Assess Ser. 2017 May 12;17[5]:1-142. eCollection 2017).
Q: What conditions should trigger endocrinologists to think about hyperbaric oxygen therapy for their DFU patients?
A: Candidates for the therapy include diabetic ulcers that have persisted for longer than 30 days, since these ulcers are at a significantly higher risk of a complicating infection, along with those that have failed treatment or are becoming more symptomatic over time (Undersea Hyperb Med. 2017 Mar-Apr;44[2]:157-60).
At that point, it might make sense to refer those patients to a wound and hyperbaric specialist for further evaluation and management, especially to a wound center that offers hyperbaric oxygen therapy.
These wound centers can be found in smaller towns. But some folks will have to travel, perhaps to a wound center at a hospital that has room and board like they do for cancer patients.