Hyperbaric Oxygen Treatment-Foot Ulcers

Citation: Diabetes Forecast, June 1993 v46 n6 p57(5)
 

Title: Hyperbaric oxygen therapy for foot ulcers. (includes related articles))
Authors: Cianci, Paul; McCarren, Marie)
 

Subjects: Diabetes Complications)
Foot Ulcers)
Ulcers Care and treatment)
Hyperbaric oxygenation Therapeutic use)
Reference #: A13917295)
 

Full Text COPYRIGHT American Diabetes Association Inc. 1993)
 

Take a breath. The air you just took in is about 21 percent oxygen. The capillaries in your lungs pick up the oxygen, and it's dissolved in the plasma of your blood and gets carried to all parts of your body. Your body uses that oxygen to heal itself, and 21 percent oxygen is usually plenty to do the job. When you have a foot ulcer, however, your body could use even more oxygen. The white blood cells that fight the infection in the ulcer use 20 times more oxygen when they're killing bacteria. Also, the more oxygen your body has to work with, the more efficiently it lays down wound-repairing connective tissue.

Yet just when you need more oxygen, you may have less. If you have neuropathy (diabetic nerve damage), that may cause changes in blood flow, resulting in islands of low oxygen levels in your foot. Less oxygen means slower healing, and an ulcer that doesn't heal could eventually lead to an amputation. So it seems that you should try to get extra oxygen in your blood when you have a foot ulcer, to bring the oxygen levels in the tissues around the ulcer up to normal, or even higher.

But sitting in your living room and breathing in 100 percent oxygen won't do the trick. Under normal circumstances, only so much oxygen will dissolve in your blood. It's like trying to dissolve salt in water. When you pour a spoonful of salt into a glass of cold water, not all of the salt dissolves. Simply adding more salt doesn't make the water dissolve more salt. But when you pour a spoonful of salt into a glass of hot water, all the salt dissolves. At higher temperatures, more salt dissolves. What temperature does for salt in water, pressure does for oxygen in blood. At higher pressures, more oxygen dissolves.

Breathe Deep—In A Way

You can make more oxygen dissolve in your blood by going into a pressurized chamber and breathing 100 percent oxygen. This is called hyperbaric oxygen therapy. (Hyper means high, baric means barometric, or atmospheric, pressure.) The pressure in a hyperbaric chamber is the same as if you went scuba diving 33 feet under water. When you breathe 100 percent oxygen while you're at that pressure, your blood has about 15 times more oxygen dissolved in it than it does normally.

Hyperbaric oxygen (HBO) therapy isn't a new treatment. The technology was developed in the late 1800s and was first used to treat decompression sickness ("the bends") in deep-sea divers who swam up to the surface too fast. Today, HBO is also used to treat carbon monoxide poisoning, serious burns, and radiation damage—all conditions in which not enough oxygen is getting to the tissues.

Some studies have suggested that hyperbaric oxygen therapy is effective, when used with other therapies, in treating diabetic foot ulcers and preventing amputations due to ulcers. But HBO therapy isn't magic. It won't work unless it's part of an aggressive team approach. To get your ulcer to heal, you will need tight blood glucose control, aggressive removal of dead tissue, infection control, correction of circulation problems, good nutrition, and, possibly, hyperbaric oxygen therapy.

How It's Done

Some centers have walk-in chambers. You sit or recline in an air-pressurized chamber, possibly with one or more people, while you breathe oxygen through a mask or head tent. At other centers, you will lie in a one-person chamber, and the entire chamber is pressurized and filled with oxygen. But even in a chamber of this type, it is the inhaled oxygen, which is then absorbed by your blood after you breathe it, that speeds wound healing, not the oxygen drifting past the wound. (You may have seen advertisements for devices that encase a person's leg and deliver oxygen to the skin. This is not hyperbaric oxygen therapy, and it's not effective—your skin doesn't absorb oxygen that way. These devices may even reduce the amount of oxygen that gets to your leg.)

If your ulcer is not infected, treatment once a day for two hours is enough to stimulate healing. You can do this as an outpatient.

However, if your ulcer is infected and there is a high risk of amputation, you will need treatment twice a day for 90 minutes. Usually, treatments will continue for three to four weeks. In most cases, you'll have to be hospitalized and be put on antibiotics. If you take insulin, your doctor may need to change your dose while you are in treatment. The average cost for an entire course of treatment is $8,000. Medicare and insurance companies cover HBO treatments when they are used as part of an aggressive program of wound management.

Effects Of Hyperbaric Oxygen Therapy

Oxygen levels remain high in tissues for several hours after a treatment, which encourages capillary growth. New capillaries mean more blood gets to the site of the ulcer, which speeds healing. High oxygen levels also make red blood cells more flexible so they can get through the twists and turns of the capillaries and get to where they're needed.

Although high doses of oxygen can produce a reduction in blood flow to normal tissue, this effect is more than made up for by the 10- to 15- fold increase in the amount of oxygen dissolved in the plasma. And sometimes you want less flow—as long as the flow is rich in oxygen—such as when your foot is already swollen.

There are, however, some side effects of HBO therapy.

Side effects due to pressure

During the pressure changes, your ears will pop, as they do when you fly in an airplane or drive in the mountains. If your ears can't equalize the pressure, such as when you are congested with a cold or hay fever, your ears or sinuses could be damaged. Therefore, you shouldn't have treatments when you are congested. Some people with chronic ear trouble may need to use ear tubes to continue therapy. These are surgically inserted but not permanent.

People can suffer a collapsed lung during treatment. Lung problems are very rare, occurring in about 1 in 50,000 treatments. You will need special consultation and medical clearance if you have active asthma, emphysema, or other lung problems that would put you at high risk for problems. Older people sometimes find that, after treatment, their vision improves, and they can read fine print better. Unfortunately, this effect lasts only a few weeks.

Oxygen Toxicity

Oxygen is a drug with definite overdose and toxic effects, usually affecting the central nervous system or lungs. Long exposure to high doses of oxygen under pressure can cause grand mal seizures. This happens in about 1 in 10,000 treatments and is reversed by stopping HBO treatment. Therapy can continue after the seizure stops. Susceptibility varies widely, but as oxygen in the blood goes up, so does the risk of oxygen seizures. For this reason, oxygen seizures. For this reason, oxygen treatments are limited to a maximum depth equal to diving 66 feet under water. Fever and certain medications can predispose you to oxygen seizures, so tell your doctor what drugs you are taking.

High oxygen levels can cause irritation of the lung tissue, but treatment schedules have been refined, and this complication is virtually unheard of in the United States today.

Confinement Anxiety

Because HBO treatments take place in closed chambers, some people get anxious. Sedation can help, but some patients can't tolerate treatment because of claustrophobia.

For You?

Hyperbaric oxygen therapy is not for everyone. Before you start HBO treatments, you will be assessed by a doctor specially trained in diving and hyperbaric medicine to see if HBO therapy is right for you.

You need good blood flow in the arteries of your feet for HBO therapy to be effective. If the doctor finds that you have reduced arterial blood flow, you will be referred to a vascular specialist. Correcting the vascular specialist. Correcting the vascular problem may solve the ulcer problem without HBO treatments.

We don't recommend hyperbaric oxygen treatment for trivial ulcers that are likely to respond to more traditional therapy. We use HBO therapy on patients with deep ulcers that have gone into the connective tissue or bone, or who have infections or gangrene (dead tissue) and where loss of a limb is a possibility.

Where Do I Go?

There are over 400 hyperbaric oxygen therapy centers throughout the United States and Canada. Most are in hospitals, and many of these are associated with universities. They are staffed by specially trained doctors, nurses, and technicians. The Undersea and Hyperbaric Medical Society (9650 Rockville Pike, Bethesda, MD 20814) is an international scientific organization and the leading authority for hyperbaric medicine in the United States. They can tell you of a program near you.