Recompression therapy (hyperbaric oxygen therapy) involves giving 100% oxygen for several hours in a sealed chamber at pressures higher than 1 atmosphere.

Recompression therapy has four effects on the blood that can be useful in treating diving injuries:

• Increasing the concentration of oxygen
• Decreasing the concentration of nitrogen
• Decreasing the concentration of carbon monoxide
• Decreasing the size of gas bubbles

Among divers, recompression therapy is used most often for decompression sickness and arterial gas embolism, but it also may occasionally be used to treat carbon monoxide poisoning. Recompression therapy is often referred to as hyperbaric oxygen therapy when it is given primarily to administer high concentrations of oxygen rather than to treat decompression sickness or arterial gas embolism. Hyperbaric oxygen therapy is used for several disorders unrelated to diving. Whether recompression therapy is effective for all these disorders is still being studied.

Disorders Treated With Hyperbaric Oxygen Therapy
Treatment with hyperbaric oxygen therapy seems to benefit people with some disorders. These include Air embolism Clostridial infection (a severe bacterial infection of soft tissues) Decompression sickness Death of bone caused by radiation therapy (osteoradionecrosis) Poorly healing skin grafts Severe carbon monoxide poisoning It is not clear whether treatment with hyperbaric oxygen therapy helps people with other disorders, and studies of recompression therapy in these disorders are still being done. Blockage of the large artery or vein that supplies the retina in the eye Brain abscess caused by actinomycosis Infection with “flesh-eating bacteria” (necrotizing fasciitis) Severe anemia in people with low blood pressure Severe bone infection (osteomyelitis) Severe crushing injury, usually of a limb Severe burns Soft tissue injury caused by radiation therapy Wounds in limbs that have poor blood supply

The sooner therapy is begun, the better the result is likely to be. Some chambers have room for more than one person and some have room for only one. Treatments are usually given once or twice daily for 45 to 300 minutes. Most often, 100% oxygen is given at 2.5 to 3 atmospheres of pressure.

Recompression therapy is relatively safe, but doctors try to avoid using it in people who have any of the following:

• Chronic lung disorders
• Sinus problems or colds
• Seizure disorders
• Claustrophobia
• Recent chest surgery
• Collapsed lung (pneumothorax)
• Recent ear surgery or injury
• Fever

Recompression therapy is usually avoided during pregnancy unless the mother's life is in danger because of possible harmful effects of high oxygen concentrations on the fetus. Recompression therapy can cause problems similar to those that occur with barotrauma (see Diving and Compressed Air Injuries: Barotrauma). It can also cause temporary nearsightedness, low blood sugar levels, or, rarely, toxic effects on the lungs or seizures.

Information regarding the location of the nearest recompression chamber, the most rapid means of reaching it, and the most appropriate source to consult by telephone should be known by most divers. Such information is also available from the Divers Alert Network (919-684-8111; www.diversalertnetwork.org) 24 hours per day. The Undersea and Hyperbaric Medical Society (membership.uhms.org/?) is another valuable information source.

Last full review/revision February 2009 by Alfred A. Bove, MD, PhD