Pulmonary edema: Nursing

Pulmonary edema refers to the buildup of fluid in the lungs; and this can be further classified as cardiogenic pulmonary edema, which occurs as a result of heart disease; and noncardiogenic pulmonary edema, which usually occurs in the presence of damaged pulmonary capillaries.

To understand pulmonary edema, first, let’s quickly review the lower respiratory tract, which includes the lower part of the trachea, and the lungs containing the bronchi, bronchioles, alveolar ducts, and finally the alveoli. Alveoli are tiny air-filled sacs that are surrounded by tiny blood vessels, called capillaries.

Zooming in even more, we can see a tiny space between the alveolar wall and the capillary wall, called the interstitial space, which normally contains a small amount of interstitial fluid. And that’s where most gas exchange occurs.

So, each time we breathe in, the inhaled oxygen moves through the alveolar membrane, the interstitial space, and then through the capillary membrane to reach the blood, which is brought back through the pulmonary veins into the left heart and further into the systemic circulation.

On the other hand, carbon dioxide is carried from the right heart, through pulmonary arteries, into the lungs, where it diffuses from the capillaries through the interstitial space and into the alveoli, and then gets breathed out.

Now, cardiogenic pulmonary edema is caused by inadequate pumping of the heart, which usually occurs because of left-sided heart failure, ventricular arrhythmias, myocarditis, myocardial infarction, or valvular disorders, as well as severe hypertension and cardiomyopathy.