Small airway disease in chronic obstructive pulmonary disease: insights and implications for the clinician.

PURPOSE OF REVIEW: Small airway disease (SAD) is a common feature in chronic obstructive pulmonary disease (COPD) patients. Chronic exposure to cigarette smoking causes inflammation, damage, tissue remodelling and eventually airway loss. These features lead to airflow limitation and defective alveolar ventilation. The aim of this review is to provide clinicians with an up-to-date perspective of SAD in COPD. RECENT FINDINGS: In this review, we will discuss the key pathological features of SAD. We also review state-of-the-art techniques for measuring SAD, including impulse oscillometry and lung imaging methods. We discuss emerging concepts such as SAD in the earlier stages of COPD and the relationship between SAD and emphysema. SUMMARY: The current review highlights the importance of targeting small airways early in the course of COPD to tackle disease progression.