The previous Figures showed some of the evidence that NIV for treatment of chronic hypercapnic respiratory failure due to COPD is associated with improvements in HRQOL, in blood gases, and, in some instances, in lung function parameters. However we have also seen that NIV using low IPAP levels was not able to significantly impact long-term survival of patients with COPD.

This Figure shows the study design of a German multicenter study that compared noninvasive positive pressure ventilation (NPPV) versus standard treatment for patients with severe stable COPD.^[5] In this study NIV was targeted to reduce baseline PaCO₂ by ≥20% or to achieve PaCO₂ values, expiratory positive airway pressure (EPAP) of about 5 mbar, and a breathing frequency (Bf) of 16 breaths/min.