The purpose of this study is to learn more about new ways to detect injury or disease in the small airways of the lung.
Spirometry, the most commonly used lung function test, often does not detect disease in small airways. A type of breathing test called the lung clearance index (LCI) has shown promise in detecting small airway diseases in those with conditions such as cystic fibrosis. We will conduct LCI testing in people with chronic lung disease, as well as healthy participants with no history of lung disease, to see if this technique helps to detect abnormalities in small airways. We also will conduct spirometry testing and compare the results to LCI testing to determine if LCI is more effective in detecting abnormal lung function.