What does a decreased FEV1/FVC ratio typically indicate?

• A. Restrictive disease
• B. Obstructive disease
• C. Normal lung function
• D. Cardiac dysfunction

Answer: (B)

A decreased FEV1/FVC ratio typically indicates obstructive disease. In pulmonary function testing, FEV1 (forced expiratory volume in one second) represents the amount of air a person can forcibly exhale in one second, while FVC (forced vital capacity) is the total amount of air that can be forcibly exhaled after taking the deepest breath possible.

In obstructive lung diseases, such as asthma or chronic obstructive pulmonary disease (COPD), there is an impediment to airflow due to narrowing or blocking of the airways. This results in a significant reduction in FEV1 while FVC may be relatively preserved or decrease to a lesser extent. As a result, the ratio of FEV1/FVC declines, reflecting the obstruction in airflow.

On the other hand, restrictive diseases, such as pulmonary fibrosis, affect lung volume and usually present with a normal or increased FEV1/FVC ratio since both FEV1 and FVC are reduced proportionately. Normal lung function would show a normal FEV1/FVC ratio, typically around 0.7 or higher, while cardiac dysfunction would not inherently cause a decrease in the FEV1/FVC ratio, as it pertains more to the mechanics of breathing rather than the