A.70%~90% B.50%~70% C.30%~50% D.10%~30% E.<10%
A.PaO2/Fi0>300 B.200<PaO2/Fi0<300 C.200<PaO2/Fi0<400 D.PaO2/Fi0<200 E.PaO2/Fi0<100
A.20%~25% B.25%~29% C.35%~45% D.50%~60% E.95%~100%