Study of Humidified Air to Improve Mucociliary Clearance (MCC) in COPD

Chronic bronchitis is a component of Chronic Obstructive Pulmonary Disease (COPD), along with emphysema. COPD is associated with smoking, exposure to environmental pollutants, or occupational exposures. In the airways mucus acts to trap inhaled toxins or pathogens. In a healthy lung mucus is cleared by mucociliary and cough clearance. Mucociliary clearance involves the synchronous motion of cilia underneath the mucus sheet that lines the airways. This drives the mucus sheet out of the airways (like a conveyer belt) continually clearing particulate and pathogens. In chronic bronchitis, mucus is overproduced due to toxic stimuli. Mucus clearance may also be defective due to airway obstruction and insufficient cough. This results in the accumulation of mucus that contributes to airway obstruction. Therapies for improving mucus clearance may decrease the degree of airway obstruction experienced by COPD patients. Heated, high-flow, humidified air or oxygen may improve mucus clearance by hydrating the mucus in the airways and may also help to increase airway patency. A similar intervention was shown to improve mucus clearance in subjects with bronchiectasis. The investigators have developed nuclear imaging-based methods for measuring mucus clearance from the lungs. These techniques have been applied to evaluate novel therapies for the treatment of cystic fibrosis lung disease. Here the investigators will apply these techniques to determine whether treatment with heated-humidified air will improve mucus clearance in subjects with COPD. Study participation involves 3 visits. Study day 1 includes: 1. A conversation with a physician and completion of informed consent 2. Pulmonary function testing (including albuterol administration) 3. The completion of a series of questionnaires Study days 2 and 3 include: 1. A urine pregnancy test (if applicable) 2. Performance of a Co57 transmission scan 3. The inhalation of a radiopharmaceutical (Technetium-99m sulfur colloid) from a nebulizer 4. Lying flat in a nuclear medicine camera for 90 minutes while scans are collected. 5. Remaining at the test center for a follow up scan approximately 2.5 hours later. This scan will take 10 minutes. 6. Nasal delivery of heated humidified air (with supplemental oxygen if needed) at a rate of 30 liters per minute through a nasal cannula, on one study day. This will be started during the first 10 minutes of the 90 minute scanning period and continued for 4 hours. One the other study day there will be no treatment so that a baseline measurement of mucociliary clearance can be made. The order of the study days will be randomized. Participants will be asked to refrain from using short-acting beta agonist (SABA) medications for 6 hours prior to study days 2 and 3, and long-acting beta agonists (LABA) or long-acting muscarinic antagonists (LAMA) for 24 hours prior to study days 2 and 3.