What is pulmonary edema?
Pulmonary edema is collection of fluid within the lungs. This is different from pleural effusion, which is collection of fluid between the inner and outer coverings of the lung. The most important cause of pulmonary edema is heart failure, specifically, failure of the left ventricle, lower muscular chamber which pumps oxygenated blood to the rest of the body. Pulmonary edema can also occur when there is fluid overload in the body as in kidney failure.
Other causes of pulmonary edema are obstruction to the mitral valve (valve between the left upper (left atrium) and left lower (left ventricle) chambers of the heart, obstruction to the blood vessels draining oxygenated blood from the lungs to the left atrium (pulmonary veins) and increased permeability of the small blood vessels of the lungs (noncardiogenic pulmonary edema – e.g. adult respiratory distress syndrome or ARDS).