In obstructive pulmonary diseases, there is a decrease in which of the following?

• A. Airflow
• B. Compliance
• C. Lung volume
• D. Vital capacity

Answer: (A)

In obstructive pulmonary diseases, the primary characteristic is a decrease in airflow, particularly during expiration. Conditions such as asthma, chronic obstructive pulmonary disease (COPD), and emphysema lead to narrowed airways, increased resistance to airflow, and obstruction that prevents air from being expelled from the lungs efficiently.

This reduced airflow is evident in various pulmonary function tests, such as the forced expiratory volume in one second (FEV1) / forced vital capacity (FVC) ratio, which typically shows a significant decrease in FEV1 compared to FVC in these patients. This airflow limitation is central to the diagnosis and understanding of obstructive pulmonary diseases, distinguishing them from restrictive diseases, where the overall volume of air that can be inhaled or exhaled is reduced, rather than just the airflow during expiration.

In contrast, compliance and lung volumes can vary based on the individual condition and progression of the disease. While some patients may exhibit changes in lung compliance or lung volumes due to air trapping or hyperinflation, the hallmark feature of obstructive pulmonary diseases remains the impaired airflow, making it the most definitive characteristic to note. Vital capacity may or may not change significantly, but it is primarily the airflow that is markedly reduced, specifically during expiration