Pulmonary edema is a condition in which fluid accumulates in the lungs, making it difficult for a person to breathe. The fluid buildup typically occurs in the alveoli (tiny air sacs in the lungs), where oxygen exchange takes place. This impairs the lungs' ability to deliver oxygen to the bloodstream and can cause symptoms like shortness of breath, wheezing, coughing (often with frothy or pink-tinged sputum), and a feeling of suffocation