Recompression therapy involves giving 100% oxygen for several hours in a sealed chamber at pressures higher than 1 atmosphere.
(See also Overview of Diving Injuries.)
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
Treatment in a hyperbaric chamber with oxygen 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.
The sooner recompression therapy for decompression sickness is begun, the better the result is likely to be. However, recompression may be helpful even if started up to several days after surfacing. 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 up to 300 minutes. Most often, 100% oxygen is given at 2.5 to 3 atmospheres of pressure.
During pregnancy a single recompression treatment for an acute illness such as decompression sickness or carbon monoxide poisoning is generally considered safe. However, multiple hyperbaric oxygen treatments are usually avoided during pregnancy because of possible harmful effects of high oxygen concentrations on the fetus. Recompression therapy can cause problems similar to those that occur with barotrauma. It can also cause temporary nearsightedness, low blood sugar levels (hypoglycemia), 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 (919-684-9111; www.diversalertnetwork.org) 24 hours per day.