Pulmonary oedema is a medical term describing build-up of fluid in the lung tissues caused by a back-pressure from a failing left side of the heart. Fluid is pushed out of the blood vessels, causing the lungs to become like a sponge, thus inhibiting
Any sudden onset of shortness of breath must be reviewed by a physician.
See the relevant section here with regard to the treatment of the underlying cause.
A sudden onset may be helped by Aconite 6 or