Non-invasive Ventilation in Severe Chronic Obstructive Pulmonary Disease(COPD)

The key problem of COPD (Chronic Obstructive Pulmonary Disease) is chronic inflammation and obstruction of the small airways. This results in a largely elevated flow resistance and work of breathing. The lungs develop enlarged air spaces (emphysema) with a reduction of alveoli and respiratory surface. Consequences are flattening of the diaphragm and alterations in the thoracic skeleton. COPD patients in advanced stages develop insufficiency of the muscular ventilatory pump. The ventilatory pump may decompensate, if the load of the muscles overruns their capacities. Besides that, an unphysiologically high proportion of the cardiac pump volume must be spent for the demands of the ventilatory muscles. Hypercapnia, and later hypoxaemia, are indicators of a decompensated ventilatory pump. Theoretically, non-invasive ventilation (NIV) could be a treatment option for patients with advanced COPD and insufficiency of their ventilatory pump. Mechanical non-invasive ventilation provides support for the ventilatory muscles and might counterbalance the elevated intrinsic PEEP. The physiologic and quality of life aspects of long term application on non-invasive ventilation (over at least one year) will be assessed in this study.