Every day in the U.S., approximately 150 people have limbs amputated secondary to diabetes—that’s 57,000 per year, approximately 50% of which are probably preventable, according to the Agency for Healthcare Research and Quality.
One element of an effective management strategy can be hyperbaric oxygen therapy (HBOT), which has been found in several randomized trials to reduce the number of patients requiring a large amputation by 30% to 50%.
HBOT results in high arterial PO2, which leads to increased tissue oxygenation and reversal of areas of hypoxia. The patient is placed in a sealed chamber and breathes 100% oxygen after the pressure inside has been gradually increased.
For years, HBOT was known primarily as a treatment for divers experiencing decompression sickness, but now many hospitals are discovering its potential in the inpatient and outpatient treatment of a number of other conditions, particularly selected non-healing wounds and chronic tissue damage from radiation therapy. Medicare recently added diabetic wounds of the lower extremities to its list of conditions for which HBOT is reimbursable (see ).
A growing field
Interest in the use of HBOT is growing, according to Duke University’s Center for Hyperbaric Medicine and Environmental Physiology in Durham, N.C. “It offers efficacy for certain kinds of refractory wounds, which can be a major management challenge,” he said. “It’s another therapeutic piece that can be offered to patients with non-healing wounds of certain types, particularly for wounds in irradiated areas and diabetic wounds.”
Although the cost of HBOT can seem high—up to $20,000 for the typical course of some 20 to 24 treatments—it pales beside the cost of an amputation, which is at least $140,000 for surgery, aftercare, and items such as prosthetics, as well as an additional $20,000 to $40,000 per year in maintaining the amputation, according to Mike Comer, CEO of the wound care management company Wound Care Advantage in Sierra Madre, Calif. “Even more alarming, the morbidity rate goes up extraordinarily after an amputation, which is not surprising considering the patient has less mobility and more medical issues,” Mr. Comer said. “That puts you at risk of another amputation.”
The treatment is not without adverse effects. Some 10% to 20% of patients will experience otic barotrauma—injury from pressure effects on the middle ear. This, the most common side effect, is usually resolved without major morbidity using topical vasoconstrictors and, occasionally, tubes in the ears. “It’s possible that the eardrum could rupture, but I’ve never seen it happen,”
The second most common side effect is ophthalmic oxygen toxicity, which usually affects patients who require multiple courses of treatment (as many as 30 to 50). “Patients can develop a change in the refractive index of the eye, inducing nearsightedness,” Dr. Moon said. “It usually resolves, although not always.”
Rarely, hyperbaric oxygen can cause convulsions, but Dr. Moon noted that this is fairly unusual; no patients at his facility have had convulsions in well over two years.
Multiplace versus monoplace chambers
Estimates vary, but it’s thought that between 500 and 700 U.S. facilities currently offer HBOT, said Virginia Mason Medical Center in Seattle. About 80 of these are accredited by the Undersea and Hyperbaric Medical Society (see ). Some of these institutions, such as Duke and Virginia Mason, have invested millions of dollars in major specialty hyperbaric medicine programs, which include large “multiplace” chambers that can accommodate multiple patients as well as nurses or other skilled caregivers.
Multiplace chambers are usually designed for each specific institution and are expensive to build and maintain. “Installing a multiplace chamber either requires constructing a building or taking a roof off or a wall out to install it. And once you have the chamber in place, you need more staff, because with more people in the chamber, the more likely it is that a patient will need a drug or other supplies, or otherwise need tending, “ said Dr. Moon. Virginia Mason’s new multiplace treatment facility, for example, cost $7.1 million to install in 2005. It occupies 8,000 square feet and can treat up to 17 patients at a time. While the initial investment for multiplace chambers is high, for large hospitals they are cost-effective and more readily suited for treating critically ill patients, according to Dr. Moon.
Monoplace chambers, which accommodate only one patient at a time, are much less costly. “These can be put in a double hospital room; the space requirement for a hyperbaric unit with two monoplace chambers is about 900 square feet,” said Dr. Hampson. The cost for a top-of-the-line monoplace chamber is currently about $160,000, according to Perry Baromedical, a Florida-based manufacturer.
Whatever the type of chamber, an appropriately staffed hyperbaric program should have a trained physician directly on-site to supervise operations. A 2000 report from the Department of Health and Human Services’ Office of the Inspector General found that the quality of HBOT varies widely throughout the U.S. but improves when there is physician oversight. Since the OIG report highlighted the issue, such oversight has improved dramatically, experts say.
“It raised hospitals’ awareness that this was a valid concern,” says Robert Warriner III, MD, executive vice president of medical affairs for Diversified Clinical Services in Jacksonville, Fla., which collaborates with some 300 hospitals across the U.S. offering wound care programs. “I used to go to hospitals and get a lot of pushback on physician supervision, saying that the doctors wanted to do other things, but I have no difficulty today when I go in and say that a physician must be physically in the area during hyperbaric therapy. Hospitals understand the value in outcomes and safety; the bar has clearly been raised.”
Although most hospital-based hyperbaric oxygen facilities tend to be primarily outpatient—often tied to outpatient wound care centers—hospitalists frequently manage such programs, Dr. Warriner said. “These are programs that suit the hands-on management skills of the hospitalist.”
Some controversy has surrounded hyperbaric medicine because of its occasional application for indications that have not yet been approved by the Undersea and Hyperbaric Medical Society and the FDA. Such conditions may have lower levels of supporting evidence than the current reimbursable indications. For example, said Dr. Moon, some have touted HBOT as a treatment for cerebral palsy and multiple sclerosis, but trials have not borne out its efficacy for these conditions.
There may well be further applications for HBOT in the future, however, according to Dr. Moon. One that he thinks will soon be approved is a central retinal artery and vein occlusion, which involve sudden-onset blindness. “Both conditions seem to respond to hyperbaric oxygen, and because of their rarity, there will probably never be a randomized trial. Besides, when dealing with such devastating conditions, the notion of a clinical trial is trumped by the desire to pull out all the stops,” he said.
Developing an HBOT program requires an “institutional and personal commitment” on the part of the hospital, Dr. Hampson said. He pointed out the need to train physicians, nurses, and chamber operators, to commit space, and to decide whether to provide 24/7 coverage for emergencies.
“It’s a big investment,” he said. “But on the other hand, do you want to send diabetic wound care patients, radiation necrosis patients, or someone with carbon monoxide poisoning who comes to your emergency department 100 miles away to the hospital that did make that commitment?