Just what is an air embolism?
An air or gas embolism is a bubble that becomes trapped in a blood vessel and blocks it. This can lead to many different symptoms depending on where the blockage occurs. It’s one of the leading causes of death among divers.
An air or gas embolism can happen when a scuba diver surfaces too quickly from any depth. This can cause air to escape into the blood vessels from the lungs (pulmonary barotrauma) or bubbles of nitrogen to form in the blood vessels (decompression illness, or “the bends”).
An embolism can develop in an artery or vein. When an air bubble travels along an artery, it moves through a system of blood vessels that gradually become narro-wer. At some point, the bubble may block a small artery and cut off the blood supply to a particular area of the body.
Bubbles in the veins travel around the body and can cause breathing difficulties when they reach the lungs.
How serious is it?
The seriousness of the blockage depends on which part of the body the affected blood vessel supplies blood to and the size of the air bubble. For example, an air embolism in:
The arteries to the brain can cause immediate loss of consciousness and may lead to seizures (fits) or a stroke – it can also cause confusion, dizziness and slurred speech.
The coronary arteries (which lead to the heart) may cause a heart attack or an abnormal heart rhythm.
A blood vessel to the lungs may cause a pulmonary embolism.
These conditions are very serious and can be fatal, particularly if an air embolism is not recognised and treated promptly.
Even with treatment, some people who survive are left with permanent brain damage, although this is very rare.
Divers should always be carefully monitored by their colleagues and supervisors so any air or gas embolism can be immediately identified and treated.
Signs and symptoms of an air embolism can include joint or muscle pains, low blood pressure, which may cause dizziness, an irregular heartbeat, breathlessness and fast breathing, blurred vision, chest pain, strong feelings of anxiety and itching of the skin, a faint blue tone to the skin (cyanosis), bloody froth from the mouth, paralysis or weakness, possibly of one or more limbs, seizures (fits) and/or loss of consciousness
If a scuba diver develops these symptoms within 10 to 20 minutes of surfacing, they probably have an air embolism and should be given 100% oxygen and transferred to hospital as soon as possible, preferably one with a recompression chamber.