HBOT acts on any exogenous gas bubble formed after:

• a rapid ascent of a diver
• too rapid decompression of an astronaut
• a medical puncture

Circulatory bubbles prevent blood flow or damage tissues. HBOT causes a massive influx of oxygen in the body, instantly oxygenating the tissues.

HBOT immediately compresses the bubbles which shrink.

Air bubbles contain too much nitrogen for rapid spontaneous elimination. HBOT creates an oxygen gradient that quickly removes excess nitrogen and shrinks further the bubble.

Paradoxically, after the bubbles disappear, the resumption of circulation leads to additional tissue damage. HBOT produces high levels of oxygen free radicals that help enhance cellular defenses and prevent damage (see reperfusion injury).