In moderate severity obstructive lung disease, the expected abnormalities include the following except-
In moderately severe obstructive lung diseases,FEV1/FVC ratio will be less than 0.7 and FEV1 will be 50-80% predicted.TLC will be increased,FRC is more severely elevated due to loss of lung elastic recoil & dynamic hyperinflation.RV is very severely elevated due to airway closure.Vital capacity will be decreased.So FRC/TLC will be increased in obstructive lung diseases. Reference:Harrison's Medicine-20TH edition
(upward arrow) Residual capacity
(downward arrow) Vital capacity
(downward arrow)FRC/TLC ratio
FEV1/ IFVC<70%
Respiratory system