By Susan Steeves
WebMD Medical News Archive

Nov. 7, 2001 -- Last year, a surgeon told Thelma Bell that wounds on her right foot had progressed to gangrene and she was facing amputation. She'd already lost two toes because of nerve and circulatory damage caused by diabetes.

But within a few weeks, Bell's wounds were nearly healed, and the tissue on her foot appeared pink and healthy. Her foot and leg were saved, and doctors predicted that once she was fitted with a special shoe, she should be able to walk normally.

Bell escaped the fate of the estimated 86,000 people each year who have lower limb amputations because of complications of diabetes; they account for half of all leg and foot removals performed annually in the U.S. Her outcome was different because of wound care aided by hyperbaric oxygen therapy, says Jeffrey Stone, DO, MPH.

Stone, director of the hyperbaric medicine unit at the Institute for Exercise and Environmental Medicine (IEEM), is studying whether use of the therapy can reduce diabetic amputations. "One of my questions has been the role of hyperbarics in diabetic wounds," he tells WebMD.

Patients are put in a large, submarine-like chamber and don a clear plastic hood into which 100% oxygen is pumped. This increases the amount of oxygen in their blood, which in turn helps generate growth of vessels, says Stone.

Vessel growth is crucial for diabetics because they have circulatory problems due to blocked arteries and capillaries. They also have nerve problems, called sensory neuropathy, so they often can't feel cuts on their feet. "I've had patients come in with a nail in a foot and not know it," Stone says.

Once an injury occurs, it may not heal if there's not enough oxygen-enriched blood reaching the area. Often, as in Bell's case, the wound may fester until the only option is amputation.

For military veterans alone, this results in about 9,000 amputations annually at a total cost for surgery, hospitalization, medical care, and rehabilitation of $341 million, according to the Department of Veterans Affairs. Diabetics are 15 to 40 times more likely to have a leg amputated than someone not suffering from the disease.

Diabetics and others also must cope with hardening of the arteries, a condition usually treated by angioplasty, bypass, or stent placement. But there also are microvascular changes -- clogged capillaries that occur in the feet of many diabetics.

"I think it's these folks that are helped by hyperbarics," Stone says. "It's important to point out that hyperbarics is not a panacea. It isn't. There are many other things we do first such as check for infection, seeing if we can get weight off the foot, if we can control edema, help with proper nutrition, including [blood sugar] control."

Hyperbaric medicine is not new. It has been used since the 1940s to treat decompression sickness from scuba diving, carbon monoxide poisoning, and chronic bone infections. For the past 35 years, it also has been used for healing wounds.

In an earlier retrospective study, Stone and his colleagues looked at results for 1,633 patients treated for wounds over 33 months. Of those, 501 were diabetic; 119 received hyperbaric oxygen therapy and the rest received conventional treatment. They found that the limb salvage rate was 72% for those on pure oxygen and only 53% for the rest. Stone cautions that this was not a controlled study, so not a true measure of the effectiveness of hyperbarics in reducing amputation.

"Hyperbarics is important," says Stone. "It's just one of the things done to treat wounds. The majority of patients don't need hyperbarics. My average patient presents with a wound that has been there 11.8 months. I think the key in many of these cases is a multidisciplinary approach. ... We need to better define which patients will respond to hyperbarics."