An air embolism is an air bubble trapped in a blood vessel. It is the leading cause of death among divers.
An air embolism usually happens when a scuba diver runs out of air, or if they surface too quickly and hold their breath while they come up (see Air embolism - causes for more information).
When an air bubble travels along an artery, it moves through a system of blood vessels that gradually become narrower. At some point, the bubble will block a small artery and cut off the blood supply to a particular area of the body.
How serious is it?
The seriousness of the blockage depends on which part of the body the artery supplies blood to. If the embolism stops blood getting to the brain, tissue in the brain will be starved of oxygen and die. This can cause permanent brain damage.
The symptoms of an air embolism depend on where the blockage occurs. An air embolism in an artery to the brain, for example, causes symptoms similar to those of a stroke, including confusion, partial paralysis, seizures or loss of consciousness. See Air embolism - symptoms for more information.
How is it treated?
The only effective treatment for air embolism is immediate recompression treatment in a hyperbaric chamber (see Air embolism - treatment for more information). This reduces the size of the air bubbles inside the body and restores normal bloodflow and oxygen to the tissues.
