Hyperbaric Therapy for CO Poisoning and Decompression Sickness

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.


The FDA has approved the therapy for several 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, tasteless 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 (most common), 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 CO poisoning in many people can be reversed 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




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.


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. Others may have nearsightedness that usually gets better within days to weeks after the last treatment. According to experts, undergoing hyperbaric oxygen therapy at a hospital with trained staff is the best way to avoid more serious side effects. 

Online Medical Reviewer: Eric Perez MD
Online Medical Reviewer: Kenny Turley PA-C
Online Medical Reviewer: Maryann Foley RN BSN
Date Last Reviewed: 8/1/2020