**9. Conclusion**

For COPD exacerbations NPPV should now be considered as a standard of care in properly selected patients, used in preference to invasive mechanical ventilation. Available evidence and experience have indicated that NPPV has an important role in managing COPD exacerbations, markedly by reducing the need for intubation and improving outcomes, including lowering complication and mortality rates, as well as shortening the hospital stay. NPPV can also be used in certain other situations in COPD patients: in respiratory failure precipitated by a superimposed pneumonia, in postoperative respiratory failure, in intubated patients to facilitate extubation with the aim of reducing the complications of prolonged intubation, in patients with postextubation failure to avoid reintubation, and in do-not-intubate patients; although the evidence to support these applications is not as strong as for NPPV in typical COPD exacerbations. For patients with severe stable COPD, currently available evidence suggests that NPPV can improve daytime and nocturnal gas exchange, prolong sleep duration, improve quality-of-life scores, and possibly reduce the need for hospitalization. However, the findings among studies have not been consistent on these benefits, partly related to numerous methodological shortcomings in most studies performed to date. Despite the weakness of the evidence base, however, some of the consensus and guidelines agree that COPD patients with substantial daytime carbon dioxide retention and evidence of superimposed nocturnal hypoventilation are the ones most likely to benefit (ACCP consensus conference 1999). Achieving desired NPPV adherence by COPD patients will remain still a challenge. Identification of eligible patients, establishment of the appropriate settings and close monitoring of the patients with trained staff are the key points of success of NPPV therapy. Technological improvement of NPPV devices and masks besides new guidelines on the selection of patient, ventilation mode and interface may achieve better NPPV adherence in patients with COPD in the future.
