USPS stands for United States Postal Service. (regular mail). UPS stands for United Parcel Service. This is a courier service and offers many different levels of service with a wide range of delivery times and prices.
Fluid in the lungs is a broad term to describe two possible conditions that may give characteristic symptoms, like a bubbling sound in the lungs (rales) when breathing. The fluid accumulation may be inside the lung (pulmonary edema) or outside the lung (pleural effusion), in the space between the lung and chest wall.
My mom had fluid drained from her lung, which came back as cancer. We are waiting for pathology to come back to see if they can determine the source. The fluid is re-accumulating at at rapid rate and she is in so much pain.