Airway clearance in cystic fibrosis.

Airway clearance is considered an integral component of standard therapy for cystic fibrosis (CF) patients. Although the pathophysiology of CF has not been conclusively delineated, most of the theories revolve around the development of viscous airway secretions.1–4 These secretions are thought to be poorly cleared from the lung, leading to airway obstruction and infection with Staphylococcus aureus and Haemophilus influenzae early in the disease, followed by Pseudomonas aeruginosa later in the disease.5,6 Chronic inflammation either secondary to abnormal mucus and bacterial infection or related to the underlying defect then leads to airway injury, airway fibrosis, and bronchiectasis.7 There is clear evidence that CF patients have abnormal mucociliary clearance and mucus plugging very early in the disease.8,9 Pathophysiologic reasoning suggests airway clearance makes sense and could modify the course of the disease. The goal of airway clearance techniques is to enhance clearance of airway secretions, thus potentially limiting the bacterial burden and decreasing inflammation in the conducting airways. Theoretically, to substantially alter the natural history of the disease, airway clearance should be started early in the course of the disease. Thus the scientific basis for this therapy is very sound.