Measurement and Analysis of Maximal Expiratory Flow Volume Loops at Low Lung Volumes in Children With Cystic Fibrosis and Normal Routine Lung Function

What this Trial Is About

This research aims to identify hidden small airways obstruction in children and adults with cystic fibrosis who have normal results on routine pre-bronchodilator lung function tests. It focuses on patients with both heterozygous and homozygous cystic fibrosis and explores the presence of lung issues not detected by usual spirometry measures like FEV1, FVC, and their ratios. The study builds on previous findings that small airways obstruction and emphysema can exist despite normal routine lung function tests. Participants undergo diagnostic tests including spirometry and lung CT scans to detect abnormal expiratory airflow at low lung volumes, which may indicate small airways obstruction or peripheral airway bronchiectasis. The study is retrospective and observational, assessing maximal expiratory flow volume loops at 75% and 80% expired lung volume to find airway limitations that routine tests might miss. During the study, researchers analyze existing lung function data and imaging results to measure small airway obstruction in cystic fibrosis patients. The main outcome is the detection of unsuspected small airway obstruction over a 5-year period. Participants' routine spirometry results are reviewed alongside specialized measurements to better understand lung function in this population, helping to inform future diagnosis and management strategies.

Detection of Unsuspected Small Airways Obstruction in Cystic Fibrosis