Pulmonary edema means you have fluid building up in your lungs. That can make it hard for you to breathe.
Normally when you take a breath, your lungs fill with air. If you have pulmonary edema, they fill with fluid instead. When that happens, oxygen from the air can’t get from the lungs into the blood where it’s needed.
When it comes on suddenly it's called acute pulmonary edema, and can it be life threatening. If you have any of these symptoms, call 911 right away:
Sudden shortness of breath