These air bubbles can travel to your brain, heart, or lungs and cause a heart attack , stroke , or respiratory failure . Air embolisms are rather rare.

An air embolism, also called a gas embolism­, occurs when one or more air bubbles enter a vein or artery and block it. When an air bubble enters a vein, it’s called a venous air embolism. When an air bubble enters an artery, it’s called an arterial air embolism.

An air embolism can occur when your veins or arteries are exposed and pressure allows air to travel into them. This can happen in several ways, such as:

Injections and surgical procedures

A syringe or IV can accidentally inject air into your veins. Air can also enter your veins or arteries through a catheter that’s inserted into them.

Air can enter your veins and arteries during surgical procedures. This is most common during brain surgeries. According to an article in the Journal of Minimal Access Surgery , up to 80 percent of brain surgeries result in an air embolism. However, medical professionals usually detect and correct the embolism during the surgery before it becomes a serious problem.

Doctors and nurses are trained to avoid allowing air to enter the veins and arteries during medical and surgical procedures. They’re also trained to recognize an air embolism and treat it if one does occur.

Lung trauma

An air embolism can sometimes occur if there’s trauma to your lung. For example, if your lung is compromised after an accident, you might be put on a breathing ventilator. This ventilator could force air into a damaged vein or artery.

Scuba diving

You can also get an air embolism while scuba diving. This is possible if you hold your breath for too long when you’re under water or if you surface from the water too quickly.

These actions can cause the air sacs in your lungs, called alveoli, to rupture. When the alveoli rupture, air may move to your arteries, resulting in an air embolism.

Explosion and blast injuries

An injury that occurs because of a bomb or blast explosion can cause your veins or arteries to open. These injuries typically occur in combat situations. The force of the explosion can push air into injured veins or arteries.

According to the Centers for Disease Control and Prevention (CDC) , the most common fatal injury for people in combat who survive blast injuries is “blast lung.” Blast lung is when an explosion or blast damages your lung and air is forced into a vein or artery in the lung.

Blowing into the vagina

In rare instances, blowing air into the vagina during oral sex can cause an air embolism. In this case, the air embolism can occur if there’s a tear or injury in the vagina or uterus. The risk is higher in pregnant women, who may have a tear in their placenta.