A.小于13cmHO(1.3kPa)
B.13~24cmHO(1.27~2.35kPa)
C.30~50cmHO(2.94~4.90kPa)
D.13~30cmHO(1.27~2.94kPa)
E.25~50cmHO(2.45~4.90kPa)