Study of Ambulatory Respiratory Assist Device in Chronic Obstructive Pulmonary Disease Patients

Inclusion Criteria: 1\. Moderate to severe COPD (by ATS criteria) 1. FEV1/FVC \<0.70 2. FEV1 \< 60% Predicted Exclusion Criteria: 1. Physical limitation that prevents walking for 6 minutes (e.g. lower extremity amputation, arthritis limiting function, significant angina, etc…) 2. Lung pathology not explained by COPD, which may limit functional capacity (e.g. pulmonary fibrosis, malignancy, history of lung reduction surgery, etc…) 3. Pregnancy 4. Age \<18