Negative Pressure Ventilator in Long-term Pulmonary Rehabilitation for Chronic Obstructive Pulmonary Disease
Negative Pressure Ventilator in Long-term Pulmonary Rehabilitation for Chronic Obstructive Pulmonary Disease
Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow
 obstruction with chronic airway inflammation and emphysematous changes in the lung
 parenchyma, thus leading to air-trapping, as well as extional dyspnea. The investigators have
 previously observed that NPV used as an adjuvant to pulmonary rehabilitation improves lung
 function, exercise capacity, and reduces exacerbations. The investigators now sought to
 determine whether long-term maintenance NPV improves long-term clinical outcomes and reduces
 mortality in COPD.
Chronic obstructive pulmonary disease (COPD) is characterized by irreversible airflow
 obstruction with chronic airway inflammation and emphysematous changes in the lung
 parenchyma, thus leading to air-trapping, as well as extional dyspnea. The mechanism
 underlying desaturation during 6MWT in patients with COPD is multifactorial involving dynamic
 hyperinflation and impaired gas exchange that worsens ventilation-perfusion mismatch.
 Previous studies have shown that oxygen desaturation during the 6MWT predicts mortality and
 increases the risk of adverse outcomes in COPD patients. However, there is a paucity of
 studies that have looked at effective treatments to counter the consequences of hypoxemia
 during exertion.

 The investigators have established a hospital-based maintenance pulmonary rehabilitation
 program together with NPV for COPD, and the investigators have shown that the benefits of NPV
 improves lung function and exercise capacity, and reduces acute exacerbation and medical
 costs. The investigators now sought to determine whether long-term maintenance NPV improves
 long-term clinical outcomes and reduces mortality in COPD.
Inclusion Criteria:

 -  Main diagnosis of Chronic Obstructive Pulmonary Disease

 -  Stable status at enrollment

 -  Able to come to pulmonary rehab center

 Exclusion Criteria:

 -  Infection or acute excerbation condition at enrollment

 -  Severe neuromuscular, cardiac disease or dementia

 -  Unable to perform six minute walk test