Advanced Patient Assessment Practice Exam

What mechanisms explain why patients with COPD may have a poor cough?

1. Increased elastic recoil

2. Weak muscles of breathing

3. Airway obstruction

4. Decreased lung compliance

The correct answer is: Increased elastic recoil

In patients with Chronic Obstructive Pulmonary Disease (COPD), the mechanics of coughing can be significantly impaired, and one of the contributing factors is the reduced elastic recoil of the lungs. In COPD, especially in emphysema, the destruction of alveolar walls leads to a loss of elastic fibers. This loss impairs the lung's ability to recoil after inhalation, which is critical for effective coughing. Coughing relies on both the strength of the respiratory muscles and the elastic properties of the lungs to generate adequate intrathoracic pressure for expelling mucus and secretions. When elastic recoil is diminished, the efficiency of the cough reflex is compromised, leading to a shallow and less effective cough. Weak muscles of breathing can contribute to this scenario, but they are not the primary mechanism as elastic recoil plays a more direct role in the effectiveness of the cough. Similarly, while airway obstruction is a hallmark of COPD, it leads to increased difficulty in expelling air rather than directly affecting cough strength. Decreased lung compliance typically describes a different set of pulmonary issues more aligned with restrictive lung diseases, rather than the obstructive nature seen in COPD. Thus, impaired elastic recoil is a crucial factor in understanding the poor cough seen in these patients.