When SCUBA diving, additional oxygen and nitrogen dissolve in the body tissues, excess nitrogen is washed out of tissues during decompression. During or after ascent this excess nitrogen gas can bubble into the blood much like carbon bubbles out of a soda solution when the cap is removed. Theses bubbles cause symptoms which are known as decompression sickness. Symptoms of decompression illness include joint pain, rash, fatigue, weakness of the extremities, dizziness, changes in hearing, paralysis and loss of consciousness. Decompression illness is a medical emergency best treated within a hospital setting.
Hyperbaric oxygen works by providing oxygenation, promoting clearing of nitrogen and decreasing the volume of nitrogen through direct pressure.