American Board of Surgery Qualifying Exam (ABS QE) Practice Test

In restrictive lung disease, how is the FEV1 typically affected?

1. Increased FEV1

2. Decreased FEV1

3. Normal or increased FEV1

4. Variable FEV1

The correct answer is: Normal or increased FEV1

In restrictive lung disease, the primary characteristic is a decrease in lung volume rather than a significant obstruction of airflow. This condition can arise from various factors including lung parenchymal disease, pleural disease, or chest wall disorders. In cases of restrictive lung disease, although the FEV1 (Forced Expiratory Volume in one second) often is reduced along with the FVC (Forced Vital Capacity), the key outcome is that the ratio of FEV1 to FVC remains normal or may even increase. This is because both FEV1 and FVC decrease proportionately. Therefore, the standardized measure of airflow obstructiveness, often represented as FEV1/FVC, indicates either a normal or possibly increased FEV1 in relation to the reduced total capacity of the lung. This nuanced understanding highlights that while the absolute values of FEV1 might be lower due to decreased lung volume, the ratio indicates that the flow is not obstructed, consistent with restrictive physiology.