Pulmonary edema describes a condition in which fluid builds up in the lungs, making it difficult to breathe. Most often, the buildup of fluid is caused by a pressure imbalance within the heart, but other causes can also send excess fluid to the lungs. If the fluid is arriving at a faster rate than the lungs can clear it, parts will fill, making it difficult—if not impossible—for the lungs to take in oxygen and deliver it to the rest of the body, as they are meant to do.

People who experience pulmonary edema may struggle to breathe; the feeling has been described as being like drowning or suffocating. Some people cough up a thick, pink, frothy liquid while struggling for air.

Pulmonary edema can be a life-threatening condition. Immediate medical attention is essential. Extra oxygen can be given to help patients breathe more effectively, while other treatments to remove fluid from the lungs and manage the heart-related pressure problems that caused the fluid buildup can also make a difference.

“Fortunately, pulmonary edema is a reversible condition, and the faster it is treated, the better the outcome is likely to be,” says Yale Medicine pulmonologist Isabel Bazan, MD.

Pulmonary edema is a condition in which too much fluid accumulates in the lungs, interfering with a person’s ability to breathe normally. The problem is usually related to heart disease, but it has other possible causes, including kidney failure, blood transfusion reactions, or travel to destinations at high elevation.

When the heart and lungs are functioning normally, the organs are able to manage fluid movement within the body, including the exchange of fluid between the heart and lungs. But sometimes, a problem within the chamber on the left side of the heart (the left ventricle) creates excess fluid pressure and causes blood to pool, which can overwhelm the lungs.

When fluid comes into the lungs too quickly for them to clear it effectively, the excess fluid is shunted into the lung’s tiny, delicate air sacs; these are meant to hold gas, not fluid, and are critical for breathing. This is why the sensation feels like drowning. Pulmonary edema is an emergency situation, because people with the condition are not receiving the oxygen they need.

Pulmonary edema tends to affect older adults, particularly those with heart failure: Up to 80% of people with heart failure also have pulmonary edema. Men are affected more often than women.

Several conditions may cause pressure within the left side of the heart, leading to excess fluid to enter the lungs.

• Heart conditions – including congestive heart failure, coronary artery disease, arrhythmia, and heart-valve problems, may prevent blood from being propelled forward properly. This can contribute to the build-up of pressure and pooling of blood within the heart’s left ventricle, causing too much fluid to leak into the lungs.
  
• Heart attack, stroke, and injuries to the lungs (including pneumonia), kidneys (including kidney failure), or liver may also contribute to increased pressure within the heart, leading to excess fluid in the lungs.
  
• Other factors, such as being at a higher altitude than one is accustomed to (especially if there is physical exertion) or taking certain medications can also lead to pulmonary edema.

People with pulmonary edema may experience some or all of the following symptoms:

• Trouble breathing, or shortness of breath
• Feelings of anxiety related to breathing difficulties
• Wheezing or noisy breathing
• Quick, shallow breathing
• Trouble breathing while lying down
• Discomfort related to breathing
• A feeling of suffocation
• Coughed-up sputum that appears frothy and pinkish, if blood is present
• Pale or bluish skin
• Sweating or feeling clammy
• Swelling in the feet or ankles
• Confusion

Although some people without heart disease experience this condition, most cases of pulmonary edema are linked to heart problems. The risk increases among people with heart conditions who don’t take their medication as prescribed and don’t follow their doctor’s nutrition advice.

People who are at increased risk of pulmonary edema include those with:

• Congestive heart failure
• Heart-valve problems, which lead to backward blood flow within the heart
• Irregular heartbeat (arrhythmia)
• High blood pressure (hypertension)
• Heart attack
• Stroke
• Pneumonia
• Liver disease
• Kidney disease or injury
• Lung injury

Additionally, visiting destinations at high elevations may increase the risk of pulmonary edema.

People who are having trouble breathing should visit the emergency department as soon as possible.

There isn’t one single test that doctors use to diagnose pulmonary edema. Rather, they find out about someone’s medical history, give them a physical exam, and order tests to make a diagnosis.

Doctors will ask people about their current symptoms and if they’ve experienced heart failure, arrhythmias or other heart problems, including heart attack. They will also ask about other illnesses, like pneumonia or kidney disease.

The physical exam is an important aspect of care. When doctors listen to a person’s lungs with a stethoscope, they may hear what are known as crackles, which indicate that fluid is present.

Doctors may also order tests to confirm pulmonary edema or to rule out other conditions, including:

• Chest X-ray
• Electrocardiogram
• Pulse oximetry, to measure blood-oxygen levels
• A blood test to check certain hormone levels, which could indicate pulmonary edema
• A pulmonary capillary wedge pressure test, in which a catheter is inserted in a blood vessel to measure pressure in the heart’s left ventricle

People with breathing problems associated with pulmonary edema need to be treated quickly. They’ll be asked to sit upright during treatment, which helps improve breathing.    

Common treatments for pulmonary edema include:

• Supplemental oxygen, may be delivered via a nasal cannula
• Medications, including diuretics (to rid the body of excess fluid); nitroglycerin (to help lower pressure within the heart); inotropes (to help the heart pump more efficiently); and/or ACE inhibitors (to manage blood pressure levels)
• Morphine, which can help reduce anxiety and improve breathing.
• Continuous Positive Airway Pressure (CPAP), another method to improve breathing
• Ventilators, which require intubation, may improve breathing when other methods are unsuccessful
• Renal replacement therapy, when pulmonary edema causes kidney failure

Pulmonary edema can be life-threatening. People who are diagnosed with the condition may already be in heart failure, or they may have had a heart attack or stroke. Other chronic health conditions may complicate their care.

People who seek treatment may recover, but about 20% of people who are treated for pulmonary edema die, often due to complications. Among those who do recover, the lungs usually function normally again after 6 months or a year, if not sooner. 

“Yale’s Pulmonary & Critical Care program is one of the top ranked programs in the country,” says Dr. Bazan. “Doctors from this specialty are experts in managing pulmonary edema. Intensivists collaborate with heart doctors, kidney doctors, and other specialists to provide patient-centered and high-quality care to every patient.”