Specific Aim I directly tests the hypothesis that mucus clearance is impaired due to mucus dehydration. It measures 1) COPD Mucociliary and Cough Clearance 2) mucus hydration 3) the concentrations of the dominant regulators of airway hydration and 4) the consequences of mucus dehydration on mucus biophysical properties and bacterial infection.
Specific Aim II tests the hypothesis that COPD acute exacerbations are associated with failures of mucus clearance. Measurements will be similar to that of Specific Aim I, but conducted during periods of baseline health, acute exacerbation and recovery.
Specific Aim III tests whether airway surface hydration with 7% Hypertonic Saline will restore clearance in the basal state and during a COPD acute exacerbation. COPD subjects will be exposed to inhaled Hypertonic Saline during periods of baseline health and acute exacerbation. Acute efficacy via measures of mucus clearance and spirometry will studied.
