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Hyperbaric Oxygen Therapy

Other common name(s): hyperbaric medicine, hyperbarics, HBOT, HBO2

Scientific/medical name(s): none


Hyperbaric oxygen therapy (HBOT) involves the breathing of pure oxygen while in a sealed chamber that has been pressurized at 1-1/2 to 3 times normal atmospheric pressure.


Research has shown HBOT can help when used as a mainstream treatment for the prevention and treatment of osteoradionecrosis, a term for delayed bone damage caused by radiation therapy. There is also some evidence suggesting HBOT may be helpful as an extra treatment for soft tissue injury caused by radiation. There is no evidence that HBOT cures cancer. The U.S. Food and Drug Administration (FDA) has approved HBOT to treat more than a dozen health problems such as decompression sickness, carbon monoxide poisoning, gangrene, brain abscess, and injuries in which tissues are not getting enough oxygen.

How is it promoted for use?

Hyperbaric oxygen therapy is used in conventional treatment for decompression sickness; severe carbon monoxide poisoning; certain kinds of wounds, injuries, and skin infections; delayed radiation injury; and certain bone or brain infections. Decompression sickness, commonly known as "the bends," is an extremely painful and potentially dangerous condition that strikes deep sea divers who surface too quickly and, occasionally, miners and tunnel builders who come up too rapidly. It can also affect fighter pilots who climb very quickly.

Claims about alternative uses of HBOT include that it destroys disease-causing microorganisms, cures cancer, relieves chronic fatigue syndrome, and decreases allergy symptoms. A few supporters also claim that HBOT helps patients with AIDS, arthritis, sports injuries, multiple sclerosis, autism, stroke, cerebral palsy, senility, cirrhosis, Lyme disease, and gastrointestinal ulcers. Available scientific evidence does not support these claims. Because of that, the FDA has sent a warning letter to at least one manufacturer about promoting HBOT for unproven uses. The FDA considers oxygen to be a drug, meaning it must be prescribed by a physician or licensed health care provider to treat illnesses or health conditions.

What does it involve?

HBOT can be done in single-person chambers or chambers that can hold more than a dozen people at a time. A single-person chamber, or monoplace, consists of a clear plastic tube about seven feet long. The patient lies on a padded table that slides into the tube. The chamber is gradually pressurized with pure oxygen. Patients are asked to relax and breathe normally during treatment. Chamber pressures typically rise to 2.5 times the normal atmospheric pressure. Patients may experience ear popping or mild discomfort, which usually fades if the pressure is lowered a bit. At the end of the session, which can last from thirty minutes to two hours, technicians slowly depressurize the chamber.

After an HBOT session, patients often feel lightheaded and tired. Monoplace chambers cost less to operate than multiplace chambers and are fairly portable. Medicare, Medicaid, and most health insurance policies cover medically approved uses of HBOT.

What is the history behind it?

In the early 1900s, Orville Cunningham noticed that people with some heart diseases did better if they lived closer to sea level than at high altitudes. He successfully treated a colleague with influenza who was near death due to lung restriction, and later developed a hyperbaric chamber. After his attempts to use HBOT to treat a host of other conditions failed, the method was abandoned and his chamber was scrapped.

HBOT chambers were developed by the military in the 1940s to treat deep-sea divers who suffered from decompression sickness. In the 1950s, HBOT was first used during heart and lung surgery. In the 1960s, HBOT was used for carbon monoxide poisoning, and it has since been studied and used for a number of health-related applications. It has been the subject of a great deal of controversy because of the lack of scientific proof to support many of the other uses for which it is suggested.

What is the evidence?

There is scientific evidence showing HBOT works to treat a number of conditions. The Committee on Hyperbaric Oxygen Therapy of the Undersea and Hyperbaric Medicine recommends it for treatment of:

  • Decompression sickness
  • Arterial gas embolism (bubbles of air in the blood vessels)
  • Carbon monoxide poisoning (with or without cyanide poisoning)
  • Delayed radiation injury of the soft tissue or bones, including osteoradionecrosis
  • Gas gangrene (a serious infection)
  • Skin grafts and flaps that are not healing well with standard treatment
  • Soft tissue infections in which tissues are dying (necrotic)
  • Anemia due to severe blood loss (when transfusions are not an option)
  • Crushing injuries in which there is not enough oxygen to the tissues
  • Certain wounds that are not healing with standard treatment
  • Thermal (heat) burns
  • Abscess in the brain or head
  • Osteomyelitis (chronic bone inflammation) that does not respond to standard treatment
  • Blockage of the retinal artery (blood vessel in the back of the eyeball)

These are considered to be proven uses of HBOT. For some of these conditions, HBOT is the preferred treatment. For some others, HBOT is one of many treatment options to consider. There is conflicting evidence about whether HBOT is helpful in treating fast-spreading infections of the skin and underlying tissues.

A Swedish study of 94 people with diabetic foot ulcers were divided into 2 groups: one group used HBOT for 85 minutes a day, 5 days a week, for 8 weeks (40 treatment sessions) for treatment, and the other had placebo sessions. Of the group that was supposed to get HBOT, 52% of them had ulcers that were healed at 1 year, while 29% in the placebo group were healed. Of those in the treatment group who actually got more than 35 HBOT sessions, the healing rate was higher, at 61% in the treatment group. This may reduce the risk of foot amputation in some diabetic patients, but more study is needed to be sure that it works. It would also be useful to find out which patients are most likely to be helped by this procedure.

Early evidence had suggested HBOT might help people with lymphedema (swelling in arms or legs after surgery, which can happen after modified radical mastectomy or other treatments in which lymph nodes are removed or irradiated). A controlled clinical trial published in 2010 looked at 58 women after breast cancer surgery and radiation to the armpit area. There was no difference in arm size between women who had HBOT and those who had standard care, either right away or 12 months after treatment.

The lack of randomized clinical studies makes it hard to judge the value of HBOT for many of its claims. Available scientific evidence does not support claims that HBOT stops the growth of cancer cells, destroys germs, improves allergy symptoms, or helps patients who have chronic fatigue syndrome, arthritis, multiple sclerosis, autism, stroke, cerebral palsy, senility, cirrhosis, or gastrointestinal ulcers.

Carefully controlled scientific studies are still going on to find out whether HBOT may be helpful for cluster headaches, migraines, heart attacks, and other conditions.

Are there any possible problems or complications?

HBOT is a relatively safe method for selected patients getting approved medical treatments. Complications are lessened if pressures within the hyperbaric chamber stay below three times the normal atmospheric pressure and sessions last no longer than 2 hours. There are some people who should not get HBOT, however.

Milder problems associated with HBOT include claustrophobia, fatigue, and headache. More serious complications include myopia (short-sightedness) that can last for weeks or months, sinus damage, ruptured middle ear, and lung damage. A complication called oxygen toxicity can result in seizures, fluid in the lungs, and even respiratory (lung) failure. Patients at high risk of oxygen toxicity may be given "air breaks" during which they breathe ordinary air rather than pure oxygen for short periods during treatment.

People with severe congestive heart failure may have their symptoms worsened by HBOT. Patients with certain types of lung disease may be at higher risk of collapsed lung during HBOT. Pregnant women should be treated with HBOT only in serious situations where there are no other options. People getting certain chemotherapy drugs (such as bleomycin, doxorubicin, or cisplatin) should not get HBOT. Anyone getting disulfiram (Antabuse) or using sulfamylon cream should not get HBOT, nor should anyone with a collapsed lung.

A person with a pacemaker, high fever, or even a cold can be harmed by HBOT. Someone with claustrophobia would likely have trouble being in the HBOT chamber.

Hyperbaric oxygen chambers can be a fire hazard: fires or explosions in hyperbaric chambers have caused about 80 deaths worldwide. Medical hyperbaric chambers today are generally well-built and have good safety records, but certain cautions must always be observed.

Relying on this treatment alone and delaying or avoiding conventional medical care for cancer may have serious health consequences.

To learn more

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-227-2345).

Dietary Supplements: What Is Safe?

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer


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Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 04/14/2011
Last Revised: 04/14/2011