What is Venous Air Embolism? Air Bubbles in Vein

Venous air embolism is a condition where air bubbles are present within the blood in the veins. This is a very serious condition that most often occurs after surgery and other medical procedures. The air bubble may eventually reach a narrow vein where it will block the flow of blood.

This condition can also occur in divers, pilots and astronauts where the change in environmental pressure allows gases dissolved in blood to return to to the gaseous state and form bubbles. Here it is known as decompression sickness, or more commonly as the bends. However, most instances of a venous air embolism occur within the hospital environment from catheterization or surgical procedures where a person is sitting upright.

Why does a venous air embolism occur?

Reasons for air bubbles in the veins

Air usually does not enter a blood vessel unless it is forced in with an infection since the veins are a close system. However, sometimes when an open vein is exposed to the external environment, and the heart is still pumping, it can suck some air bubbles into the system. A small amount of air bubbles will not cause a problem. Instead it will dissolve into the tissues and a person will not even experience symptoms. Larger amounts of air though can be dangerous.

In most cases the air is accidentally forced into the vein during a surgical or diagnostic procedure. This may happen when the IV line or catheter is not bled of the air properly. The needle is then inserted into the vein and the moving blood in the vein will quickly “suck” in this air from the IV line. Air bubbles will then travel through larger and large veins until it enters the right side of the hear where all veins empty their oxygen deficient blood. It is as this point that there is a major risk of complications.

The right side of the heart pushes blood to the lungs through the pulmonary arteries. The newly oxygenated blood will then reach the left side of the heart through the pulmonary veins. These pulmonary blood vessels are small and an air bubble can block it. As with a clot, it can cause pulmonary embolism which is a very serious and potentially life threatening condition. Death may occur shortly afterwards if a person does not receive treatment.

Similarly if the air bubble gets lodges in the coronary artery supplying blood to the heart or in a blood vessel in the brain, then it can cause a heart attack or stroke respectively. The air bubble in a small blood vessel acts in the same way as a solid blood clot – it hampers blood flow. When in the vein, it prevents blood from draining out of an area and the pressures rises in that area.

What causes a venous air embolism?

Causes of air bubbles in the veins

There are various different causes of venous air embolism. It is first important to clarify a few points. Venous air embolism is a form of gas embolism. This means that a gas bubble in the blood can travel through the bloodstream to cause an obstruction at some point. Other gases can also have this effect. Air embolism is specifically where the bubble is composed of air from the external environment. These bubbles can occur in the artery or veins, where it is referred to as arterial embolism or venous embolism respectively.

Venous air embolism may occur with :

• Surgery of the brain and spinal cord (neurosurgery) or ear and throat (otolaryngology) where a person is in the sitting position during the surgical procedure. Other procedures of the head, neck and upper chest may also hold a risk.
• Cesarean section and laparoscopic gyncological procedures, or air entering the pregnant uterus with force can also raise the risk of a venous air embolism.
• Intravenous (IV) lines, catheter insertion  or removal (catheterization) and a lumbar puncture (cerebrospinal fluid extracted from the lower spine) are procedures also hold the risk of an air embolism.
• Air blown into a body cavity during insertion of an endoscopic device, fluids like contrast dye infused into the bloodstream through a catheter and mechanical ventilation may also be the cause of venous air embolism.

What are the symptoms of venous air embolism?

Symptoms of air bubbles in the veins

The degree of symptoms depends on the amount of air that has entered the venous circulation and the location. Small amounts of air and air that enters at the periphery are less likely to cause symptoms. The closer to the right side of the heart and the brain that air enters the bloodstream, the more severe the symptoms and the more dangerous the consequences. The symptoms of a venous air embolism is not significantly different from a heart attack, pulmonary embolism or stroke. In fact the air bubbles can cause these conditions.

The combination of milder symptoms of these conditions may give rise to the presentation of venous air embolism. These symptoms includes :

• Dizziness
• Constant cough
• Chest pain
• Nausea
• Anxiety
• Disorientation

It is important to take note of specific symptoms a heart attack, stroke and pulmonary embolism.

What is the treatment for venous air embolism?

Treatment of air bubbles in the veins

A venous air embolism is a medical emergency. It needs to be diagnosed, treated and managed by medical professionals in the hospital environment. The patient needs to lie on the left hand side so as to prevent the air bubble from reach the right side of the heart. Oxygen will have to be administered to increase the blood oxygen levels and possibly shrink the existing air bubble. Fluids will be administered to increase blood volume and possibly dissipate the air bubble.

It is not easy to remove an air bubble from the bloodstream. A catheter can be inserted into the right side of the heart in a bid to remove the air bubble. Administering oxygen under pressure in a chamber (hyperbaric oxygen therapy) may compress the air bubbles and allow it to be absorbed into the body tissues. Cardiopulmonary resuscitation (CPR) should be done on the unconscious patient but can also be useful in breaking up larger bubbles.

Dr. Maya Patel

She is a renowned neurologist, illuminates the path to optimal brain health. Her expert insights guide individuals to understand and nurture their brain, ensuring mental clarity, resilience, and well-being.