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What is a Pulmonary Shunt?

Mary McMahon
Mary McMahon
Mary McMahon
Mary McMahon

Pulmonary shunt is a respiratory problem where gas exchange fails to take place in the lungs, leading to low oxygen levels in the blood. This can cause problems for the patient, as lack of oxygen will injure organs and tissues. Most commonly, patients experience pulmonary shunt as a symptom of a larger respiratory problem. To treat it, doctors must determine the origins of the issue and treat them to increase the blood oxygen level.

In patients with pulmonary shunt, blood can reach the lungs successfully and the alveoli, the tiny air sacks in the lungs, are fully perfused with blood. Oxygen, however, does not enter the blood in the normal gas exchange process where carbon dioxide leaves the blood and oxygen replaces it. As a result, blood passes through the pulmonary artery, fails to pick up oxygen, and enters the pulmonary vein to return to the heart. The heart pumps the blood through the body, but it is not carrying enough oxygen, and the patient's tissues will start to experience hypoxia.

Pulmonary edema is a common cause of pulmonary shunt.
Pulmonary edema is a common cause of pulmonary shunt.

Doctors can determine the severity of the problem by calculating the shunt fraction, a reflection of much blood the heart is pumping without any oxygen. Usually, only part of the lung is involved and blood is picking up oxygen from other alveoli, providing some for the cells to use, but not enough for the patient to be healthy. It is normal for a small percentage of the blood to not carry oxygen, usually around five percent, but having low oxygen saturation can be very dangerous.

Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again.
Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again.

A common cause of pulmonary shunt is pulmonary edema, where fluid appears in and around the lungs and interferes with gas exchange. People commonly experience this issue during heart failure, when the heart cannot circulate blood effectively and patients may become very ill. Severe pneumonia and bronchitis can also cause pulmonary shunt by filling the lungs with fluids like mucus.

Some patients see improved blood gas levels with the addition of supplemental oxygen.
Some patients see improved blood gas levels with the addition of supplemental oxygen.

When a patient's oxygen saturation is low, a doctor may decide to put the patient on supplemental oxygen, increasing the chance of successful gas exchange. Doctors may also pursue other measures like medications, procedures to remove fluid from the lungs, and treating underlying heart failure and related conditions. If the patient does not receive treatment, death is an eventual possibility, as the organs will start to shut down due to hypoxia, and patients will be more vulnerable to infection and other complications as a result of their ill health.

Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a TheHealthBoard researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a TheHealthBoard researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

Learn more...

Discussion Comments

bigjim

Pulmonary shunt treatment has gotten a lot better in recent years, especially since the equipment used to diagnose heart problems is more available and accurate. Finding things like congestive heart failure and other problems and treating them can really help with this condition.

My father went in the hospital with congestive heart failure in 1983 and died two weeks later. They wanted him to have a catheterization and then maybe a bypass, but they would have had to send him to two different cities to have it done. Now, it can be done almost immediately.

Technology is a wonderful thing, but like some of you guys said all of the treatment in the world doesn't help if you don't keep up with it.

Tomislav

I think the term pulmonary shunt is very confusing. I work with children with severe disabilities and often the word shunt refers to the treatment of fluid buildup. A shunt is placed in the area of fluid build up to release the fluids.

Many of our children have shunts in their brain, and they have to have the shunt fixed over time. They call this a shunt revision.

But it seems, in the case of pulmonary shunt, it describes the problem in the lungs versus the treatment for it.

So for those dealing with this issue or other shunt issues, be sure what type of shunt the doctors and nurses are discussing as they seem to mean very different things.

MaPa

A lot of people do not like to take diuretics, or "water pills", because they make them run back and forth to the bathroom. For less mobile people this can really take up a lot of their day and sometimes they don't make it.

There are other options, like a catheter, but that hurts just thinking about it. I can see why they find all of this unpleasant, but considering the alternative it may be the lesser of two evils.

KLR650

@Nepal2016, you're right! I work in a nursing home and this kind of thing is a big problem here. People even take off their stockings after we put them on. We ask them why, they say "I don't know". So we ask them, "do you want to end up in the hospital?".

Often they just stare at us. I really do not understand why people are so stubborn about this kind of thing. I've seen what happens when it gets bad and it did not look like any fun.

My grandmother had this and it made her final years very hard on her. She was pretty good about doing what the doctor said, though.

Nepal2016

I used to work on an ambulance, and this stuff is a lot more common than you think, especially due to fluid build up, which is called edema. And people are terrible about taking really simple steps to prevent it.

Two things that I saw people not do the most were not keeping up with their medication and not doing what their doctor told them as far as wearing stockings or sitting a certain way to keep the fluid from building up in their legs. These are not things you should decide to do yourself, mind you, but not complying with the instructions your doctor gives you can land you back in the hospital, if you make it.

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    • Pulmonary edema is a common cause of pulmonary shunt.
      By: decade3d
      Pulmonary edema is a common cause of pulmonary shunt.
    • Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again.
      By: siloto
      Pulmonary circulation is the movement of blood from the heart, to the lungs, and back to the heart again.
    • Some patients see improved blood gas levels with the addition of supplemental oxygen.
      By: khunaspix
      Some patients see improved blood gas levels with the addition of supplemental oxygen.
    • Severe pneumonia may cause pulmonary shunt.
      By: Jakub Jirsák
      Severe pneumonia may cause pulmonary shunt.
    • A pulmonary shunt may be performed in response to poor oxygen saturation levels that do not respond to other treatments.
      By: Africa Studio
      A pulmonary shunt may be performed in response to poor oxygen saturation levels that do not respond to other treatments.