From: Two-dimensional shear wave elastography: a new tool for evaluating respiratory muscle stiffness in chronic obstructive pulmonary disease patients
Classification
FEV1/FVC
FEV1% predicted
Mild
< 70%
FEV1 ≥ 80% predicted
Moderate
50%≤FEV1< 80% predicted
Severe
30%≤FEV1< 50% predicted
Very Severe
FEV1< 30% predicted