Small Airways: Not Just Air Ducts – Pathophysiological Aspects and Clinical Implications

The airways smaller than 2 mm diameter are named small airways. They are essential for the transport and exchange of oxygen and carbon dioxide and at the same time play a relevant role in pulmonary mechanics, contributing to the subdivision of lung volumes. Measurement of small airway function is, therefore, crucial in patients with respiratory disease. This overview focuses on the physiological aspects of the small airways, considered as air ducts as well as determinants of pulmonary mechanics, the most common tools for evaluating their function and treatment implications.