Study of Airflow Limitation Mechanisms in Stable, Non-Smoking Asthma Patients Ages 10 to 80

What this Trial Is About

Researchers are studying chronic, stable asthmatics who do not smoke, focusing on understanding what causes expiratory airflow limitation in moderate to severe persistent asthma. This research aims to identify whether the large or small airways mainly contribute to airflow problems and to explore the role of small airway obstruction and loss of lung elastic recoil. The study also evaluates how different doses of inhaled corticosteroids affect inflammation in these airways, using exhaled nitric oxide as a marker. Measurements will also be taken during naturally occurring asthma exacerbations for comparison. Participants receive treatment with inhaled corticosteroids and long-acting beta2-agonists such as fluticasonesalmeterol or budesonideformoterol in varying doses. This is an observational study where additional treatments might include antibiotics and tapering corticosteroids. Researchers will also perform lung function studies, imaging including high-resolution CT scans, and fiberoptic bronchoscopy with optical coherence tomography to assess lung structure and function. During the study, participants will undergo regular assessments including spirometry, measurements of exhaled nitric oxide, and lung function tests over periods ranging from 20 to 60 days and up to 5 years. Data from lung autopsies of asthmatics will be compared when available. The study monitors mechanisms of airflow limitation and presence of emphysema, aiming to better understand the disease process. Participants are observed without masking or randomization, and the total follow-up can extend from months to years.

Mechanism(s) of Airflow Limitation During Exacerbation of Asthma