What Is Pulmonary Edema?

Some people in this community have experienced pulmonary edema. It's one of the symptoms that may occur during flare-ups of heart failure. So I thought it would be neat to investigate pulmonary edema. What is it? How is it treated? How can you prevent it? Here's what to know.

Congestion and fluid

Sometimes doctors refer to it in simpler terms. For instance, some doctors describe it as “water in your lungs.” I have also heard them say lung or pulmonary congestion. A diagnosis may be congestive heart failure. It’s called congestive because your lungs are congested with fluid.

How does fluid get inside your lungs?

Let’s begin by defining some terms.


This is a phenomenon where fluid seeps from your capillaries to the interstitial spaces of your body. Capillaries are the smallest blood vessels inside your body. Interstitial spaces are the tiny spaces between tissues.1

It is normal for some water to seep into interstitial spaces. When it does, this water is usually reabsorbed by your lymphatic system. The lymphatic system is a series of vessels that collect extra fluid and returns it to your veins.1-2

Heart failure causes high blood pressure. This extra pressure forces an abnormally large amount of fluid to seep from capillaries into interstitial spaces.1-2

Pedal edema

Typically, edema due to heart failure occurs in your lower extremities, such as your feet and ankles. Usually, with heart failure, edema will occur in both of your lower extremities, as opposed to just one.1

There are other causes of it besides heart failure. Still, new or worsening foot and/or ankle edema may be an early sign of acute (it’s happening now) heart failure. Early recognition of this may help you prevent a full-fledged flare-up. Call your doctor right away.1,3

Pulmonary edema

Another term for it is pulmonary venous congestion. This is when fluid seeps into your lung from the pulmonary capillaries. Pulmonary capillaries are the smallest blood vessels inside your lungs. They connect with air sacs in your lungs called alveoli. It is here where oxygen moves from your lungs to your blood.1,4-6

So, if pulmonary capillary pressure gets too high, blood/fluid seeps from them into your lungs. This fluid takes up space, thereby reducing space for your lungs to expand. This may cause you to feel like you can’t catch your breath.1,3-6

What are the symptoms of pulmonary edema?

The most common symptom is shortness of breath. Here are some terms often associated with acute pulmonary edema.

Dyspnea: This is a feeling that you can’t catch your breath.7

Orthopnea: This means that in order to breathe you have to be sitting up.7

Hypoxia: This means that less oxygen is getting to your tissues. It means your oxygen levels are low. This is a sign of severe heart failure. It means that there is so much fluid in your lungs that not enough oxygen is getting to your blood. This can cause blue tings to your lips and fingertips (cyanosis).6

Rapid and shallow breathing:. This is due to the stimulation of receptors inside your lungs called juxtacapillary receptors (J receptors).1

How can this be treated and prevented?

Medical emergency

If you are experiencing pulmonary edema, it is considered a medical emergency. It is best to seek immediate medical attention. Call 911 if you can, or have someone do it for you. If your oxygen is low, oxygen therapy can be supplied. A treatment called BiPAP can help remove some of your work of breathing and improve oxygenation. This can help make breathing easier.6

Tests and medicines

A doctor will run some quick tests. These can help determine the exact cause of your symptoms. Medicine called diuretics can make you pee. These can help remove some of the excess fluid from your body and lungs. Medicine can lower your blood pressure or make your heart a stronger pump. Other medicines can be prescribed, depending on what the tests show. Medicines you take every day can help prevent flare-ups.5

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