An air embolism, or more accurately, a gas embolism, occurs when one or more gas bubbles enter a vein or artery. This has the potential to block the passage of blood. An air embolism can be a life-threatening medical condition.
Depending on where the blockage occurs, symptoms and severity vary. Air embolism is one of the leading causes of death in the diving community.1
Air embolism can be caused by a number of factors - most commonly diving - but certain medical procedures can also cause gas bubbles in the blood. The exact prevalence of air embolisms is not known; more minor cases may go untreated and can be without symptoms.
This article will look at the causes, symptoms and diagnosis of air embolism. It will also include ways to avoid the condition when diving.
Contents of this article:
Fast facts on air embolism
Here are some key points about air embolism. More detail and supporting information is in the main article.
- Air embolisms are most often formed during scuba diving
- Air bubbles in the veins are not as serious as those in arteries
- Arterial gas embolisms can cause strokes
- Just 2-3 ml of air injected into the cerebral circulation can cause death
- Some medical procedures can cause air embolism
- An estimated 57% of orthopedic surgeries produce air embolisms
- Symptoms of air embolism include aching joints, feelings of stress, chest pain and tremors
- The best treatment for air embolism is recompression in a hyperbaric chamber
- Ways to avoid embolisms while diving include avoiding alcohol and resurfacing slowly.
What is an air embolism?
An air embolism is a gas bubble trapped within a vein or artery.
An embolism, in general, refers to anything untoward that has become trapped within the vascular system.
An air embolism, specifically, is a bubble, or bubbles, of gas trapped within the blood vessels. The bubbles will, at some point, cut off the blood supply to a particular area of the body.
Air embolism can easily cause significant and permanent damage to the central nervous system and as such must be treated as an emergency.
A venous embolism is not as serious as an arterial embolism, which is itself not as serious as a cerebral embolism. However, all of the above have the potential to cause severe damage to organs and systems if left unchecked.2
Some medical procedures can cause small amounts of air to enter the venous system; via an intravenous drip, for instance. In general, these are stopped at the lungs and do little or no harm. In rare cases, they can reach the heart and disrupt its workings.
Arterial gas embolisms are much more serious. The embolism might potentially prevent oxygenated blood from reaching the target organ and cause ischemia (an inadequate blood supply to an organ); if the heart is affected it can produce a heart attack.
If an arterial gas embolism reaches the brain, it is referred to as a cerebral embolism and can cause a stroke.
An injection of 2-3 ml of air into the cerebral circulation can be fatal. Just 0.5-1 ml of air in the pulmonary vein can cause a cardiac arrest.3
On the next page, we look at the causes and symptoms of air embolism.