Background: Nocturnal non-invasive positive pressure ventilation (NIPPV) might be beneficial in stable hypercapnic patients with chronic obstructive pulmonary disease (COPD). However, evidence remains equivocal as conflicting results have been published.
Objectives: To determine the effect of nocturnal non-invasive positive pressure ventilation via nasal mask or face mask in patients with COPD.
Search strategy: An initial search was carried out using the Cochrane Airways Group COPD RCT register using the search terms: (nasal ventilat* OR positive pressure OR NIPPV). An additional search was done by hand searching of abstracts from meetings of the American Thoracic Society, British Thoracic Society and European Respiratory Society.
Selection criteria: Randomised controlled trials in stable patients with COPD that compared nocturnal non-invasive positive pressure ventilation plus standard therapy with standard therapy alone.
Data collection and analysis: Data extraction was performed by two independent reviewers.
Main results: The only outcome for which the 95% confidence interval excluded zero was PI max. The 95% confidence interval (CI) of the other outcomes included zero. These included FEV1,FVC, PaCO2, sleep efficiency and 6-minute walking distance (6MWD). The mean effect on 6MWD was modest at 27.5 m, but the 95% CI were wide (-28.1, 81.8 m) suggesting that some patients had a big improvement. Such patients could not be identified a priori.
Reviewer's conclusions: Nocturnal NIPPV for at least 3 months in hypercapnic patients with stable COPD had no consistent clinically or statistically significant effect on lung function, gas exchange, respiratory muscle strength, sleep efficiency or exercise tolerance. However, the small sample sizes of these studies precludes a definite conclusion regarding the effects of NIPPV in COPD.