Chronic Noninvasive Ventilation for COPD May Improve Blood Gases, HRQoL

Long-term oxygen therapy not beneficial for COPD with moderate desaturation.
Long-term oxygen therapy not beneficial for COPD with moderate desaturation.
A new Cochrane review of 21 published studies examined effect of chronic noninvasive ventilation for stable and post-exacerbation COPD.

Chronic noninvasive ventilation (NIV) appears to improve daytime hypercapnia, short-term health-related quality of life (HRQoL), and possibly survival in certain patients with chronic obstructive pulmonary disease (COPD), according to findings from a Cochrane review published in Cochrane Database Systematic Reviews.

The updated review included 21 studies, including 14 new randomized controlled trials. Studies included patients who started chronic NIV either in a stable phase (17 studies) or after a severe COPD exacerbation (4 studies). All studies compared standard of care (SOC) vs SOC plus chronic NIV for at least 5 hours per night for at least 3 consecutive weeks. Primary outcomes included improvements in arterial blood gases, HRQoL, exercise capacity (stable COPD), and admission-free survival (post-exacerbation COPD).

In 9 studies of stable COPD (with 271 participants), chronic NIV for 3 months resulted in a possible minor benefit on arterial partial pressure of oxygen (PaO2) (adjusted mean difference [AMD], 0.27 kPa; 95% CI, 0.04-0.49). There was little to no benefit of NIV on PaO2in stable COPD after 12 months (AMD, 0.09 kPa; 95% CI -0.23 to 0.42) in 3 studies with 171 participants.

Additionally, the researchers found a reduction in arterial partial pressure of carbon dioxide (PaCO2) after 3 months in 11 studies with 475 patients with stable COPD assigned to NIV (AMD, -0.61 kPa; 95% CI, -0.77 to -0.45). This effect was sustained in 4 studies (n=232) for up to 12 months (AMD, -0.42 kPa; 95% CI, -0.68 to -0.16).

No effect of NIV was observed on exercise capacity, as measured with the 6-minute walking distance, after 3 months in 8 studies (n=330) (AMD, 15.5 meters; 95% CI, -0.8 to 31.7) or after 12 months in 3 studies (n=134) (AMD, 26.4 meters; 95% CI, -7.6 to 60.5).

With respect to HRQol, there appeared to be a benefit of NIV only after 3 months in 5 studies with 259 patients with stable COPD (standardized mean difference [SMD], 0.39; 95% CI, 0.15-0.62).

The review found that NIV may have also reduced the risk of all-cause mortality in patients with stable COPD across 3 studies (n=405) (adjusted hazard ratio [AHR], 0.75; 95% CI, 0.58-0.97).

Across the group of post-exacerbation COPD studies, the researchers found little to no benefit to NIV on PaO2 after 3 months in 3 studies of 234 patients (AMD, -0.10 kPa; 95% CI, -0.65 to 0.45) but a slight benefit after 12 months (AMD, -0.27 kPa; 95% CI, -0.86 to 0.32) in 3 studies (n=170). In contrast, PaCO2 reduced by NIV at 3 months in 3 studies with 241 patients (AMD, -0.40 kPa; 95% CI, -0.70 to -0.09) and after 12 months in 3 studies with 175 patients (AMD, -0.52 kPa; 95% CI, -0.87 to -0.18).

When initiated after a COPD exacerbation, the review suggests chronic NIV may have little to no benefit on HRQoL after 3 months and 12 months. There did seem to be an improvement in admission-free survival with NIV when initiated after a COPD exacerbation (AHR, 0.71; 95% CI, 0.54-0.94; 2 studies [n=317]); however, all-cause mortality did not appear to improve across 2 studies (n=317) (AHR, 0.97; 95% CI, 0.74-1.28).

The researchers of the review wrote that their findings “provide sufficient evidence for the routine application of chronic NIV in people with severe COPD who have chronic hypercapnic respiratory failure, while its place remains uncertain for people who remain hypercapnic shortly after a severe COPD exacerbation.”


Raveling T, Vonk J, Struik FM, et al. Chronic non-invasive ventilation for chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2021;8(8):CD002878. doi:10.1002/14651858.CD002878.pub3