Air Embolism

Overview

An air embolism happens when a bubble of air or other gas enters the bloodstream and travels through the blood vessels. A bubble can block blood flow at a critical point, such as in the lungs, brain, or heart. Depending on the amount of air and where it lodges, an air embolism ranges from harmless to life-threatening.

Small amounts of air that sometimes enter the circulation are often absorbed without harm. However, a large bubble or air that reaches the brain or heart can cause serious problems and is a medical emergency. Air embolism is uncommon but can occur with certain medical procedures, serious injuries, or scuba diving accidents.

Symptoms

Symptoms depend on the size of the air bubble and where it lodges. They can come on suddenly and may include:

• Shortness of breath or rapid breathing.
• Chest pain.
• A fast, irregular, or weak heartbeat, or low blood pressure.
• Stroke-like symptoms if a bubble reaches the brain, such as weakness, numbness, confusion, trouble speaking, vision changes, or loss of consciousness.
• Dizziness or fainting.
• Bluish skin color from low oxygen.
• Joint or muscle pain, and sometimes a feeling of "the bends," in diving-related cases.

Any sudden, severe symptom after a procedure, injury, or dive should be treated as an emergency.

Causes

An air embolism occurs when air gains access to a blood vessel. Causes include:

• Medical and surgical procedures, such as insertion or removal of an intravenous (IV) line or central catheter, certain surgeries, and some lung procedures, if air enters a vein or artery.
• Scuba diving, especially if a diver holds their breath and ascends too quickly, which can rupture small air sacs in the lungs and force air into the bloodstream.
• Serious chest or lung injuries.
• Childbirth or certain gynecologic procedures in rare cases.
• Air mistakenly injected with a syringe.

Risk Factors

Situations and factors that raise the risk include:

• Undergoing surgery or procedures involving large veins, the chest, or the head and neck.
• Having a central venous catheter or other invasive line.
• Scuba diving, particularly with rapid ascent or breath-holding.
• Severe trauma to the chest or lungs.
• Being on a ventilator with high pressures in some cases.

Careful technique during medical procedures and safe diving practices greatly reduce the risk.

Diagnosis

Because air embolism can be rapidly serious, diagnosis often relies on recognizing the situation and symptoms while treatment begins. Evaluation may include:

• Clinical assessment based on the setting, such as symptoms appearing during or just after a procedure or a dive.
• Monitoring of oxygen levels, heart rhythm, and blood pressure.
• Imaging such as CT scans, which can sometimes show air in blood vessels, the heart, or the brain.
• An echocardiogram (heart ultrasound) in some cases to detect air in the heart.

Speed is important, so doctors usually act on a strong suspicion rather than waiting for every test result.

Treatment

Air embolism is treated urgently. Steps may include:

• Stopping the source of air immediately, such as clamping a leaking catheter.
• Positioning the person as directed by the care team to help keep air away from critical areas.
• High-flow oxygen to help the body absorb the gas and improve oxygen delivery.
• Supportive care for breathing, heart rhythm, and blood pressure, which may include fluids and medications.
• Hyperbaric oxygen therapy, treatment in a high-pressure oxygen chamber, which is especially used for diving-related air embolism and when air reaches the brain. It helps shrink and dissolve the bubbles.

Prompt treatment improves the chance of recovery. Outcomes depend on how much air entered and which organs were affected.

Prevention

Most air embolisms can be prevented with careful practices:

• Health care teams use techniques to keep air out of IV lines and catheters and to safely place and remove them.
• Scuba divers should follow training, never hold their breath while ascending, and ascend slowly with proper safety stops.
• People with certain heart or lung conditions should discuss diving safety with a doctor before diving.
• Prompt treatment of chest injuries helps reduce risk.

When to See a Doctor

Call emergency services immediately if someone develops sudden shortness of breath, chest pain, confusion, weakness or numbness, trouble speaking, fainting, or stroke-like symptoms during or after a medical procedure, surgery, or scuba dive. Air embolism is a medical emergency, and fast treatment can be lifesaving.

For divers, any neurological symptoms or breathing trouble after surfacing should be treated as an emergency, as hyperbaric oxygen treatment may be needed quickly.

Related Topics

Frequently Asked Questions

References

1. MedlinePlus, U.S. National Library of Medicine.
2. Divers Alert Network (DAN).
3. Mayo Clinic.
4. Centers for Disease Control and Prevention (CDC).