Airway Secretion Clearance in Cystic Fibrosis

Study Design: Randomized clinical trial with pulmonary function testing obtained every three months in each of the three treatment groups. Change in slope of FEV1 will be compared. Days of hospitalization and use of oral or IV antibiotics for respiratory tract infection, quality of life, subject satisfaction, and compliance will also be compared. Sample Size: Enrollment will be completed after 180 subjects have been recruited. Fifteen CF centers will participate. Subject Selection: Subjects must have the diagnosis of CF, be \> 7 years of age and have an FEV1 \> 45% of predicted. Prescribed Therapy: Each subject will receive airway secretion clearance twice a day. Outcomes: Change in slope of FEV1; days of hospitalization and use of oral or IV antibiotics for respiratory tract infection; quality of life; subject satisfaction; compliance.