Bronchodilator response in adult patients with cystic fibrosis: effects on large and small airways.

Spirometry, body plethysmography, maximal expiratory flow-volume curves (MEFV-curves) with air and with heliox (80% He + 20% O2) before and after inhalation of bronchodilators were studied in a group of 20 adult cystic fibrosis (CF) patients. Most of them showed prominent bronchial obstruction and seven also had evidence of restrictive pulmonary disease. Large differences were observed between total lung capacity as measured with body plethysmography and with a helium dilution technique. A calculated air trapping index correlated well with parameters of peripheral airway obstruction. Both inhalation of terbutaline and ipratropium bromide caused dose-related bronchodilatation. Density dependence of expiratory flow increased significantly after terbutaline but not after ipratropium bromide. We conclude that adult CF patients with varying degrees of obstructive and restrictive pulmonary function limitation show a dose-related improvement of lung function after terbutaline and ipratropium bromide with terbutaline being probably more effective on peripheral airways than ipratropium bromide.