The abnormal preoperative pulmonary function test in a patient with severe kyphoscoliosis includes:
A. Decreased RV and TLC
B. Reduced FEV1/ FVC ratio
C. Reduced FEF 25-75%
D. Increased FRC
Correct answer : A. Decreased RV and TLC
Kyphoscoliosis is a restrictive lung disease. There is decrease in residual volume and total lung capacity. FEV1 and FVC are proportionately decreased. Hence the ratio of FEV1 to FVC remains normal or is increased. The forced expiratory flow rate (FEF) is normal. Functional residual capacity (FRC) is decreased.