What does a normal FEV1/FVC ratio indicate regarding lung function?

• A. Restrictive lung disease
• B. Obstructive lung disease
• C. Normal lung function
• D. Acute lung injury

Answer: (C)

A normal FEV1/FVC ratio signifies that lung function is within the expected range, indicating effective and adequate airflow. FEV1 (Forced Expiratory Volume in 1 second) measures the volume of air an individual can forcefully exhale in one second, while FVC (Forced Vital Capacity) reflects the total amount of air expelled after taking a deep breath.

In a healthy individual, the FEV1/FVC ratio typically falls between 70% and 80%, depending on age and other factors. A normal ratio suggests that there are no significant obstructions to airflow, as seen in obstructive lung diseases where this ratio is decreased due to increased resistance in the airways. Similarly, restrictive lung diseases would present with a reduced FVC and a preserved or increased FEV1/FVC ratio, showing an overall reduction in lung volumes but not obstructed airflow.

Because the FEV1/FVC ratio indicates that both measures fall within normal ranges, it strongly points toward normal lung function, thus confirming that respiratory mechanics are effectively operating without acute injury or other complications.