What Is an Air Embolism?

An Air Bubble in Your Blood Vessels

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An air embolism is a bubble of air that enters your arteries or veins, most often as a complication from a medical procedure. 

When these bubbles travel, they can block blood supply in different parts of the body, like the heart, lungs, or brain. This can lead to serious problems, such as a stroke. 

Fortunately, air embolisms are very rare. In this article, you’ll learn about some of the different types of air embolisms and their potential causes. You'll also learn about symptoms, diagnosis, and treatment.

Doctor checks angiogram

Reza Estakhrian / The Image Bank / Getty Images

Different Types of Air Embolism

In general, embolisms are foreign bodies that travel in the bloodstream, blocking blood vessels. When the type of embolism isn't specified, a blood clot is assumed to be the cause, such as in a pulmonary embolism. Air embolisms are much less common than embolisms caused by blood clots.

An air embolism that occurs in the veins is called venous air embolism. If an air embolism is in your arteries, you have an arterial air embolism. 

Arterial air embolisms are generally more dangerous than venous air embolisms. In some people, a venous embolism can enter the arterial system and become a venous air embolism.

Air embolisms are also sometimes named for the location where they cause problems. For example, when these air bubbles are in your brain, they are called cerebral air embolisms. 

Air Embolism Symptoms

A small air embolism often doesn’t cause any symptoms at all. Many such air embolisms may never be detected and they eventually go away on their own.

However, when they do cause an issue, the result can be serious. The type and severity of symptoms depend on the size and number of air embolisms, as well as the location where they are lodged in the body. 

When symptoms do occur, they tend to come on suddenly. Potential symptoms may include:

  • Shortness of breath
  • Continuous coughing
  • Chest pain
  • Seizures
  • Headache
  • Loss of consciousness
  • Altered thinking
  • Muscle weakness or paralysis on one side of the body

If you have any of these symptoms after a medical procedure, get immediate medical help. If you are having a medical procedure and start to notice these signs, speak up right away. 

In severe cases, an air embolism might cause a person to die very quickly from a cardiac arrest, when the heart can't pump adequately.

Causes of Air Embolism

Air embolisms cause symptoms as they travel through a person’s blood vessels. When they get stuck (because the vessel is small), they can block blood flow to the region.

Most often, air embolisms happen because of rare complications during medical procedures and surgeries. The most common scenario is an air embolism that occurs during the placement of a central line. This is a tiny tube inserted into a large vein in the neck, chest, groin, or upper arm to give medications or fluids.

However, an embolism can occur during a number of other procedures that involve your blood vessels. Examples are:

  • Angiography (imaging that uses dyes and X-rays to better see blood vessels) 
  • Tissue biopsy (taking a sample of tissue for diagnostic purposes, like tissue from the lung)
  • Hemodialysis (treatment to clean blood of wastes, salts, and fluids for patients with severe kidney disease)
  • Endoscopic retrograde cholangiopancreatography, or ERCP (a procedure to diagnose and treat problems in the gallbladder, liver, and pancreas)
  • Surgery (such as brain surgery, heart surgeries, or hip surgeries)

The following scenarios also can but rarely do cause air embolisms:

Diagnosis: Early Recognition Is Key

During diagnosis, your healthcare provider takes in the whole clinical picture, including a person’s symptoms, their exam, and their other medical conditions. 

Key to diagnosing an air embolism is the timing. Symptoms from an air embolism can start during a medical procedure that accidentally allows excess air into your veins or arteries. Or they might start shortly after (within a day or so, but often sooner).

Sometimes, imaging that is being used for the medical procedure can help locate an abnormality. For example, CT imaging (computerized tomography) for a lung biopsy may provide an image of the embolism.

This same imaging may be able to show that air is present where it shouldn’t be. In other cases, other types of medical imaging (like angiograms) might be used to show air in the veins or arteries. 

It’s important that an air embolism be diagnosed quickly so that it can be properly treated as soon as possible. This will greatly decrease the chance of major complications or death. 

How Is an Air Embolism Treated?

If the procedure causing the embolism is still in progress, the first step is stopping it and not allowing any more air to enter.

The patient also often needs to be repositioned so that they are lying on their left side, with their feet elevated and their head lowered. In this position, air embolisms are less likely to travel to the brain and heart, where they might cause the most danger.

The bubbles will slowly dissolve on their own, but clinicians can take steps to help this go more quickly. For example, the patient is also given extra oxygen to breathe, which can help decrease the size of the air embolisms and reduce tissue damage.

If it’s available, the person also might be treated in something called a hyperbaric oxygen chamber. This is especially important for people who have very serious symptoms.

What Is a Hyperbaric Oxygen Chamber?

During this treatment method, the individual goes inside a tube-like chamber, allowing the person to breathe in 100% oxygen in a pressurized environment. This gets more oxygen into your body and causes the air embolisms to shrink in size more rapidly.

Prognosis: What Can I Expect?

Prognosis varies quite a bit with air embolisms. Some people’s symptoms go away with prompt recognition and treatment. But a lot depends on the type of air embolisms that you have.

In recent years, the use of hyperbaric oxygen has improved the prognosis for many people. Unfortunately, some people still have lingering symptoms even after the air embolism is gone, like some weakness on one side of the body. And some people do die from them.

For people who have an air embolism that enters their brain, one study found that 21% of those treated with hyperbaric oxygen died within a year. At six months after the event, 75% of survivors had little or no remaining disability.


An air embolism is a very rare but potentially life-threatening complication that can occur from surgeries and medical procedures. Air embolisms cause symptoms as they travel through a person’s blood vessels, such as blocking blood flow to the region. It needs to be diagnosed and treated immediately, potentially with hyperbaric oxygen. Prognosis varies greatly.

A Word From Verywell

An air embolism can be a devastating and unexpected complication from a medical procedure. Fortunately, it’s very rare and may not be worth worrying about ahead of time. The benefits of your necessary medical procedures are likely much greater than the small risk of getting an air embolism. 

Still, knowing about this rare possibility may help you get medical attention right away if you suspect something is wrong.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Ruth Jessen Hickman, MD
Ruth Jessen Hickman, MD, is a freelance medical and health writer and published book author.