Ventilation-drive Coupling to Evaluate The Efficacy of Inhaled Bronchodilators in Patients With COPD

Exclusion Criteria

• •Patients with signs of an airway infection; Patients with an acute exacerbation during the previous 4 weeks; Patients with giant bulla(≥3cm in diameter); Patients with recent upper abdominal surgery; Patients with one or more of the following diseases: esophageal cancer, reflux esophagitis, severe obstructive sleep apnea (apnea hypopnea index\>15/hr), neuromuscular disease, or significant heart failure; Patients with poor compliance.