With pulmonary edema, fluid accumulates in the extravascular spaces of the lung. With cardiogenic pulmonary edema, fluid accumulation results from elevations in pulmonary venous and capillary hydrostatic pressures. A common complication of cardiac disorders, pulmonary edema can occur as a chronic condition or develop quickly and rapidly become fatal.
Pulmonary edema usually results from left-sided heart failure due to arteriosclerotic, hypertensive, cardiomyopathic, or valvular heart disease. In such disorders, the compromised left ventricle requires increased filling pressures to maintain adequate output; these pressures are transmitted to the left atrium, pulmonary veins, and pulmonary capillary bed.
This increased pulmonary capillary hydrostatic force promotes transudation of intravascular fluids into the pulmonary interstitium, decreasing lung compliance and interfering with gas exchange. Other factors that may predispose a person to pulmonary edema include:
infusion of excessive volumes of I.V. fluids
decreased serum colloid osmotic pressure as a result of nephrosis, extensive
burns, hepatic disease, or nutritional deficiency
impaired lung lymphatic drainage from Hodgkin’s disease or obliterative lymphangitis after radiation
mitral stenosis and left atrial myxoma, which impair left atrial emptying
pulmonary veno-occlusive disease.