A differential diagnosis of the pulmonary oedema is important because the therapeutic approach is quite different. In cardiogenic pulmonary oedema, a negative fluid balance is sought, while in cases of permeability pulmonary oedema treating the cause of inflammation has priority. The Pulmonary Vascular Permeability Index (PVPI) enables this differential diagnosis. This parameter is calculated from the relation between Extravascular Lung Water (EVLW) and Pulmonary Blood Volume (PBV). A PVPI value in the range of 1 to 3 points to a cardiogenic pulmonary oedema, while a PVPI value greater than 3 suggests a permeability pulmonary oedema.
Fig. Cardiogenic vs. permeability pulmonary oedema