pulmonary edema
As the heart fails, pressure in the veins going through the lungs starts to rise. As the pressure in these blood vessels increases, fluid is pushed into the air spaces (alveoli) in the lungs. This fluid interrupts normal oxygen movement through the lungs, resulting in shortness of breath.
Pulmonary edema may be caused by damage directly to the lung, such as that caused by poisonous gas or severe infection, as a side effect of medications, or the result of major trauma. Lung damage with a buildup of body fluid is also seen in kidney failure. Exercising at very high altitudes can also cause pulmonary edema
RADAR