Fluid in the Lungs: Early Signs and Symptoms

What happens when fluid builds up in the lungs

Normally the air sacs (alveoli) are dry, with a very thin wall between air and blood. If pressure in the lung blood vessels rises, usually because the left side of the heart is not pumping well, fluid is pushed out of the vessels into the lung tissue and then the air sacs. Oxygen cannot cross into the blood as easily, so you feel short of breath and your oxygen level drops.

Early symptoms of pulmonary edema

Fluid often builds up gradually over days to weeks, especially in heart failure. Early signs include:

• Breathlessness on exertion: getting winded climbing stairs or walking distances you used to manage
• Orthopnea: breathlessness when lying flat, relieved by sitting up or using more pillows. Lying down shifts fluid from the legs back toward the chest
• Paroxysmal nocturnal dyspnea: waking 1 to 2 hours after falling asleep, gasping and needing to sit up or go to a window
• A dry or wet cough, often worse at night or lying down, sometimes with wheezing ("cardiac asthma")
• Swollen ankles, legs or belly and sudden weight gain from fluid retention. See peripheral edema
• Tiredness, reduced exercise ability, and needing to urinate at night
• A fast heartbeat

Symptoms of acute pulmonary edema

When fluid builds up quickly, as with a heart attack, a sudden valve failure or a very high blood pressure surge, symptoms come on over minutes to hours:

• extreme breathlessness and a feeling of drowning or suffocating
• rapid breathing and anxiety
• coughing up frothy, sometimes pink sputum
• crackling or bubbling sounds when breathing
• pale, sweaty, cold skin and blue lips
• chest pain if the cause is a heart attack

While you wait for help

1. Call 911 or your local emergency number.
2. Sit upright with legs hanging down if possible. Do not lie flat.
3. Loosen tight clothing and stay calm.
4. If you have a prescribed nitroglycerin spray or tablets for chest pain, use them as directed unless you feel faint.
5. Make sure responders can get in, and gather a list of your medicines.

Causes

For the full explanation of causes, tests and hospital treatment, see pulmonary edema.

Fluid in the lungs vs fluid around the lungs

Fluid in the lungs (pulmonary edema) is in the air sacs. Fluid around the lungs, between the lung and chest wall, is a pleural effusion. Both cause breathlessness, and heart failure can cause both, but pleural effusions often cause less night-time gasping and may cause chest pain on breathing.

What doctors do

Doctors listen for crackles at the lung bases, check oxygen levels, and arrange a chest X-ray, ECG, blood tests including BNP (a marker of heart strain) and an echocardiogram. Treatment includes oxygen, diuretics ("water pills") to remove fluid, nitrates to ease the load on the heart, and breathing support with a mask (CPAP) if needed, plus treating the cause.

Preventing fluid buildup if you have heart failure

• Weigh yourself every morning after urinating and before breakfast, and act on sudden gains as your care plan says.
• Take medicines exactly as prescribed, including diuretics.
• Limit salt, and follow any fluid limit your doctor gives.
• Avoid NSAIDs such as ibuprofen, which cause fluid retention.
• Report early symptoms rather than waiting for them to become severe.

Frequently asked questions

What are the early symptoms of pulmonary edema?

Early signs are getting out of breath more easily, breathlessness when lying flat, waking at night short of breath, a persistent cough that is worse at night, swollen ankles and rapid weight gain. These suggest fluid is building up and should be checked promptly.

How do I know if I have fluid in my lungs?

Clues include breathlessness that is worse lying down, needing more pillows, waking up gasping, crackling breathing, coughing frothy sputum, and leg swelling. Only a doctor can confirm it, using a stethoscope, oxygen measurement, chest X-ray or lung ultrasound.

Can fluid in the lungs go away on its own?

Rarely, unless the cause is temporary and mild, such as slight altitude exposure after descending. Most fluid in the lungs needs treatment with diuretics and treatment of the underlying cause, such as heart failure. Severe cases are emergencies.

Is fluid in the lungs serious?

Yes. It means the lungs cannot transfer oxygen well, and it usually signals a significant heart or lung problem. Acute pulmonary edema is life-threatening and needs emergency care, but it usually responds quickly to treatment.