Pulmonary edema

fluid accumulation in the air spaces and parenchyma of the lungs

Pulmonary edema (pulmonary oedema in British English) is fluid in the lungs ("Pulmonary" means "lungs"; "edema" means "swelling" or "fluid"). Normally, the lungs fill with air when a person breathes in. From the alveoli in the lungs, oxygen goes into the blood. The blood then carries oxygen to the entire body. Every part of the body needs oxygen to survive.

Human lungs diagram

When a person has fluid in their lungs (pulmonary edema), there is not enough space left for air to get into the lungs. The person will not be able to breathe in as much air. This means not as much oxygen will get into the blood, and the body will not get the oxygen it needs.[1]



The most common cause of pulmonary edema is heart failure on the left side of the heart.[1] The left side of the heart is supposed to pump blood to the entire body. If the left side of the heart is too weak to do this, blood will back up into the lungs. This is called cardiogenic pulmonary edema. ("Cardiogenic" means "caused by the heart.")

Other, non-cardiogenic causes of pulmonary edema include:[2]



Symptoms of pulmonary edema may include:[3]

  • Difficulty breathing
  • Orthopnea (breathing is hardest when lying down)
  • Paroxysmal Nocturnal Dyspnea (this means that difficulty breathing may wake the person up when they are sleeping at night)
  • Pink, frothy sputum
  • A medical professional will hear rales when they listen to breath sounds with a stethoscope

Flash pulmonary edema


Flash pulmonary edema is a medical emergency. It is pulmonary edema that comes on very quickly. Usually pulmonary edema takes a few hours to develop. But in the worst cases of flash pulmonary edema, a person's lungs can fill completely with fluid in minutes. Flash pulmonary edema can also be caused by moving a person with pulmonary edema, or lying them down.[4]



No matter what the cause is, pulmonary edema can be treated by:[1]

  • Giving the person oxygen
  • Sitting the person straight up (this makes it easier to breathe)
  • Forcing air into the person's lungs (this is called ventilation) if needed
  • Diuretic medicines, which remove extra fluid from the body
  • Medicines like nitroglycerine ("nitro"), which reduce the pressure caused by fluid going into the lungs. Nitroglycerine can also make the blood vessels in the lungs wider, so more fluid fits into them; this can free up some extra space for air to get into the lungs.

Other treatments can focus on the cause of the pulmonary edema. For example, if a person with kidney failure has had too much salt or fluid, they can have dialysis to take away the extra fluid and salt.



  1. 1.0 1.1 1.2 Chen, M.D., Ph.D., Michael A. (May 13, 2014). "Pulmonary Edema". www.nlm.nih.gov. U.S. National Library of Medicine. Retrieved December 30, 2015.{{cite web}}: CS1 maint: multiple names: authors list (link)
  2. "Pulmonary Edema - Causes". www.mayoclinic.org. The Mayo Clinic. July 24, 2014. Retrieved December 30, 2015.
  3. "Pulmonary Edema - Symptoms". www.mayoclinic.org. The Mayo Clinic. July 24, 2014. Retrieved December 30, 2015.
  4. Kramer K, Kirkman P, Kitzman D, Little WC (Sep 2000). "Flash pulmonary edema: association with hypertension and recurrence despite coronary revascularization". Am Heart J. 140 (3): 451–5. doi:10.1067/mhj.2000.108828. PMID 10966547.{{cite journal}}: CS1 maint: multiple names: authors list (link)