Kettering Registered Respiratory Practice Exam 2026 – Complete Study Resource

The spirometry result showing a significantly lower forced vital capacity (FVC) observed at 2.1 liters compared to a predicted value of 3.5 liters indicates a reduction in lung volume. This particular pattern suggests a restrictive lung pathology rather than an obstructive condition.

Acute bronchitis typically presents with normal lung volumes unless there are complications or significant obstruction, as it primarily affects the airways rather than reducing lung volumes directly. Therefore, while acute bronchitis can lead to airway narrowing, it usually does not result in a markedly reduced FVC as described in the question.

Both sarcoidosis and cystic fibrosis can lead to restrictive patterns and reduced FVC; however, cystic fibrosis is characterized by specific pathophysiological changes, including mucus plugging and frequent infections, which may also impact airflow and lead to an obstructive pattern over time.

In this case, the clear indicator is the significantly lower FVC, aligning more consistently with a broader category of restrictive lung diseases where the lungs are unable to expand fully, which also includes conditions like sarcoidosis. However, the combination of significant lung volume reduction with symptoms related to restrictive lung disease more often suggests conditions that impact overall lung compliance rather than just obstructive airflow limitations.