Non-invasive positive pressure ventilation (ventilators) used at night by people with stable chronic obstructive pulmonary disease (COPD)

Background: Non-invasive positive pressure ventilation (NIPPV) is a method to assist or replace spontaneous breathing (or normal breathing) with the aid of a machine called a ventilator. A mask is fitted over the nose or mouth, or both and air is pushed into the lungs. It can be used as a short-term measure, during critical instances in the hospital, but also at home for longer periods in people who have raised levels of carbon dioxide in their blood. We wanted to discover whether using NIPPV at home during the night alongside standard therapy was better or worse than standard therapy alone in people with chronic obstructive pulmonary disease (COPD). COPD is a progressive disease that makes it hard to breathe. In 2002, we published our original Cochrane review looking at this. It is important to check if new studies have been published that could be added to the existing studies in the review. In this review, we performed a new search and found new studies and, therefore, this is an update of the review published in 2002.

What is individual patient data? In this review we used individual patient data. This means we collected original research data for each participant from the original researchers who performed the studies. We used this information to perform our calculations.

Review question: What is the effect of NIPPV in people with COPD on blood gases, six-minute walking distance, health-related quality of life, lung function, respiratory muscle function and sleep efficiency.

Study characteristics: The evidence is current to August 2012. We found seven studies that reported the effects of NIPPV at home. Five of these studies looked at the effects after using NIPPV compared to regular treatment (without NIPPV) for at least three months. Two studies looked for a longer period of time, for at least 12 months. The mean age of all participants included in our meta-analysis was 67 years. All studies included men and women, but 77% of participants were men. We used data from 245 people for our meta-analysis.

Results: NIPPV during the night for 3 and 12 months in people with COPD who had raised levels of carbon dioxide had no clinically or statistically significant effect on gas exchange, six-minute walking distance, health-related quality of life, lung function, respiratory muscle strength and sleep efficiency. This means we found little or no difference in the outcomes.

Quality of the results: Because some trials had very small numbers of participants, our confidence in the quality of evidence is moderate when looking at the effects on gas exchange. All seven trials measured this outcome. Other outcomes were not always measured or available leading to a lower quality of evidence for the other outcomes such as six-minute walking distance, health-related quality of life, lung function, respiratory muscle function and sleep efficiency.

Authors' conclusions: 

Nocturnal-NIPPV at home for at least three months in hypercapnic patients with stable COPD had no consistent clinically or statistically significant effect on gas exchange, exercise tolerance, HRQoL, lung function, respiratory muscle strength or sleep efficiency. Meta-analysis of the two new long-term studies did not show significant improvements in blood gases, HRQoL or lung function after 12 months of NIPPV. However, the small sample sizes of these studies preclude a definite conclusion regarding the effects of NIPPV in COPD.

Read the full abstract...

Non-invasive positive pressure ventilation (NIPPV) is effective in treating acute exacerbations of chronic obstructive pulmonary disease (COPD). Nocturnal non-invasive positive pressure ventilation (nocturnal-NIPPV) has been proposed as an intervention for stable hypercapnic patients with COPD.


To assess the effects of nocturnal-NIPPV at home via nasal mask or face mask in people with COPD by using a meta-analysis based on individual patient data (IPD).

Search strategy: 

We searched the Cochrane Airways Group Specialised Register. We performed the latest search in August 2012.

Selection criteria: 

Randomised controlled trials in people with stable COPD that compared nocturnal-NIPPV at home for at least five hours per night, for at least three consecutive weeks plus standard therapy with standard therapy alone.

Data collection and analysis: 

IPD were collected and two review authors assessed risk of bias independently.

Main results: 

This update of the systematic review on nocturnal-NIPPV in COPD (Wijkstra 2002), has led to the inclusion of three new studies, leading to seven included studies on 245 people. We obtained IPD for all participants in all included studies. The 95% confidence interval (CI) of all outcomes included zero. These included partial pressure of CO2 and O2 in arterial blood, six-minute walking distance (6MWD), health-related quality of life (HRQoL), forced expiratory volume in one second (FEV1), forced vital capacity (FVC), maximal inspiratory pressure (PImax) and sleep efficiency. The mean effect on 6MWD was small at 27.7 m and not statistically significant. Given the width of the 95% CI (-28.1 to 66.3 m), the real effect of NIPPV on 6MWD is uncertain and we cannot exclude an effect that is clinically significant (considering that the minimal clinically difference on 6MWD is around 26 m).