A.Ⅳ級(jí)FEV/FVC<70%,F(xiàn)EV<30%預(yù)計(jì)值或FEV<50%預(yù)計(jì)值,伴有慢性呼吸衰竭
B.Ⅲ級(jí)FEV/FVC<70%,30%≤FEV≤50%預(yù)計(jì)值
C.Ⅱ級(jí)FEV/FVC<70%,50%≤FEV≤80%預(yù)計(jì)值
D.Ⅰ級(jí)FEV/FVC<70%,F(xiàn)EV>80%預(yù)計(jì)值
E.0級(jí)FEV/FVC<70%,有罹患COPD的危險(xiǎn)因素