Hyperbaric oxygen therapy has helped treat a variety of illnesses. Over the years, research has shown that it can treat many conditions that involve oxygen-starved tissue.

You can get hyperbaric oxygen therapy in either a single-person chamber or tube, or a larger chamber that holds several people at a time. The chamber is then pumped full of pure oxygen, and the pressure rises to 2.5 times that of normal air pressure.

The FDA has approved the therapy for 14 conditions, ranging from severe gangrene to certain infections, burns, radiation injury, and crush injuries. Of these conditions, the two that perhaps best show the treatment's lifesaving potential are carbon monoxide poisoning and decompression sickness.

Carbon monoxide poisoning

Carbon monoxide poisoning is caused by exposure to a colorless, odorless gas known as carbon monoxide (CO). CO is found in combustion fumes. CO poisoning is usually caused by car or truck exhaust, wood stoves, and other fuel burning appliances, smoke from a fire or blocked fireplaces, nonelectric heaters, malfunctioning gas appliances, and faulty heating exhaust systems in the home or garage.

Known as a silent killer, CO displaces the oxygen in the bloodstream when the CO is mixed in the normal air you breathe. If a heater's combustion system malfunctions and CO seeps out of it, for example, the gas can kill people while they are asleep. CO poisoning typically occurs at home, in a garage or car, or in another enclosed space like a camper, trailer, or tent.

Everyone is at risk for CO poisoning from combustion fumes, especially during the winter when windows are closed. Some people are more susceptible than others. These include babies, pregnant women,  and people with heart problems, breathing problems, or anemia.

How CO poisoning is treated

CO poisoning is a medical emergency. Its main symptoms are headache, nausea, dizziness, vomiting, weakness, chest pain, and confusion. More severe CO poisoning leads to loss of consciousness and death. 

The first step is to get out of the area where CO gas is present (or suspected) and get to the hospital. If an ambulance or emergency medical team arrives, medical personnel will likely use a face mask to give pure oxygen. This is the most common treatment for CO poisoning. The face mask is generally used for about 4 hours. If person poisoned has trouble breathing on his or her own, hospital staff may hook the person up to a machine that helps him or her breathe.

CO poisoning: Why hyperbaric oxygen therapy is prescribed

Although many people with CO poisoning can be revived without hyperbaric oxygen therapy, long-term damage from CO poisoning can include harm to the central nervous system and the cardiovascular system. Several studies have shown that under certain conditions, hyperbaric oxygen therapy can cut the risk for brain injury and nerve damage.

One drawback is that many hospitals do not have a hyperbaric chamber. So, you may be transferred by ambulance or helicopter to a hospital that has one. Hyperbaric therapy is also more expensive than using the face mask to deliver oxygen.

Decompression sickness

Decompression sickness (DCS) is a rare condition that can occur in deep sea divers, aviators, miners, astronauts, mountain climbers, or people who work at high or low altitudes. It often occurs as people return quickly to a normal altitude from these heights or depths.

DCS happens when bubbles of nitrogen and other gases form in the bloodstream. The bubbles can cause dangerous symptoms throughout the body. The most common symptom is extreme, crippling joint pain at the shoulders, knees, elbows, and ankles. This pain is often referred to as "the bends."

People with DCS may also have headaches, dizziness, extreme fatigue, ringing in the ears, visual problems, chest pain and shortness of breath, a skin rash and itching, and malaise. Warning signs can also include numbness, paralysis, staggering, coughing up blood, and collapse. In rare cases, people with DCS can go into shock and die if not treated.

Divers using compressed air are at particular risk for decompression sickness, especially if they come to the surface too quickly: Those who are older, heavier, or less physically active run a higher risk.

DCS: Why hyperbaric oxygen therapy is prescribed

Hyperbaric oxygen therapy is the primary treatment for DCS. It immediately reduces the amount of bubbles in the bloodstream, fills the tissues with oxygen, and reduces dangerous swelling.

In most instances, it's critical to get treatment as soon as possible, because the symptoms of DCS can be life-threatening. Even if your symptoms disappear when you return to a normal altitude, you should still seek medical attention and possibly receive the therapy to prevent long-term damage.

Side effects of hyperbaric therapy

Typically, the hyperbaric therapy treatments for CO poisoning or DCS last for a few hours and may need to be repeated. The treatments are generally free of side effects, but side effects do sometimes occur. For example, some people's ears pop or they have mild discomfort in the chamber. These can be eased as the pressure is lowered. Some feel lightheaded when leaving the chamber. According to experts, undergoing hyperbaric oxygen therapy at a hospital with trained staff is the best way to avoid more serious side effects. 

This information is intended to be an overview of treatment options for this condition. Johns Hopkins does not offer this service at our locations.