What is the primary factor affecting airflow in obstructive diseases?

• A. Decreased compliance
• B. Increased resistance
• C. Increased lung volume
• D. Decreased elastic recoil

Answer: (B)

In obstructive diseases, the primary factor impacting airflow is increased resistance within the airways. Conditions such as asthma, chronic obstructive pulmonary disease (COPD), and bronchitis are characterized by inflammation, mucus production, and bronchoconstriction, all of which lead to narrowing of the air passages. This narrowing significantly impedes the flow of air, particularly during expiration, as the increased resistance makes it more difficult for air to move out of the lungs.

When resistance is elevated, it can be challenging for individuals to achieve the same airflow rates as healthy individuals. In obstructive diseases, this increased resistance is typically prominent, making it the most critical factor in understanding the mechanics of ventilation in these patients. In contrast, the other factors listed—such as compliance, lung volume, and elastic recoil—play different roles and become more pertinent in restrictive lung diseases rather than obstructive ones. Thus, understanding the concept of airway resistance is crucial in managing and treating obstructive lung diseases effectively.