In summary, for COPD patients who received NIPPV:

Benefits in NNT

  • 8.3% had death prevented
  • 20% had endotracheal intubation prevented
  • 1 in 12 had death prevented
  • 1 in 5 had endotracheal intubation prevented

Harms in NNT

  • 11.1% had discomfort leading to discontinuation of treatment
  • 33.3% had minor complications such as ear pain or skin damage
  • 1 in 9 had discomfort leading to discontinuation of treatment
  • 1 in 3 had minor complications such as ear pain or skin damage

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Source: Osadnik CR, Tee VS, Carson-chahhoud KV, Picot J, Wedzicha JA, Smith BJ. Non-invasive ventilation for the management of acute hypercapnic respiratory failure due to exacerbation of chronic obstructive pulmonary disease. Cochrane Database Syst Rev. 2017;7:CD004104.

Study Population: Adults with hypercapneic respiratory failure due to exacerbation of chronic obstructive pulmonary disease.

Efficacy Endpoints: Death, endotracheal intubation, hospital length of stay, discomfort leading to discontinuation of treatment, minor complications

Harm Endpoints: Discomfort leading to inability to tolerate the mask, minor complications

Narrative: Chronic obstructive pulmonary disease (COPD) is a progressive lung disease characterized by hyperinflation of the lungs, including emphysema and chronic bronchitis. COPD death rates in the United States have declined since 1999 though predominantly in males.1 Endotracheal intubation with ventilatory support for severe exacerbations is very difficult to reverse. Noninvasive positive pressure ventilation (NIPPV), if effective in avoiding endotracheal intubation, could therefore save lives and reduce suffering.

Of the seventeen studies in the Cochrane review1 all were randomized trials with parallel group design, comparing usual care plus NIPPV to usual care alone, with some variations in usual care. NIPPV was delivered via face mask, nasal mask, or either based on preference.1 A total of 1264 adults with severe exacerbation and hypercapnic respiratory failure (pH <7.35, PCO2 >45mmHg) were enrolled.

NIPPV reduced both primary outcomes including death (odds ratio 0.4, 95%CI 0.3-0.5; absolute difference 8.4%, NNT 12), and endotracheal intubation (OR 0.4, 95%CI 0.3-0.5; difference 22%, NNT 5). Length of hospital stay was also shorter with NIPPV (mean difference 3 days, 95% CI 1-6).1

Inability to comply with treatment was higher in the NIPPV group (absolute difference 11%, 95%CI 4-17%, NNH 9). Complications due to NIPPV, which included ear pain, skin breaks due to the mask, and other minor issues, occurred in nearly 1 in 3 (NNH 3). However overall complications unrelated to NIPPV were less in the two studies reporting this outcome (RR: 0.3, 95%CI, 0.1 - 0.5).

Caveats: The review authors rated the quality of evidence “moderate” mostly based on a lack of blinding, inevitable based on the nature of NIPPV. They also state, however, this is “unlikely to have affected primary outcomes.”

The efficacy of NIPPV is dependent on its being tolerated, and for every 9 patients treated, one was unable to tolerate NIPPV. Therefore, successful treatment requires a conscious, cooperative patient. Another consideration is difficulty accessing airways due to the mask. This could limit suctioning secretions and result in aspiration or atelectasis, though these data suggest such complications were not more common with NIPPV.1

Since publication of this review the European Respiratory Society/American Thoracic Society has published practice guidelines for NIPPV in patients with COPD during acute exacerbation.2 These guidelines advise against NIPPV to prevent respiratory acidosis but recommend its use to treat acute respiratory acidosis (pH < 7.35). They also recommend NIPPV for those with severe acidosis and severe distress, as an alternative to invasive ventilation.

In conclusion, NIPPV reduces mortality and endotracheal intubation in hypercapnic respiratory failure due to COPD exacerbation. Inability to comply with treatment is higher with NIPPV, however, complications unrelated to NIPPV are less common, and complications related to NIPPV are typically minor. Because of major benefits and absence of serious harms we have assigned a color recommendation of Green (Benefit > Harm) for this intervention.

Author: Bryan Zorko, MD; Michael Ritchie, MD
Supervising Editors: Kabir Yadav, MD; Allan Wolfson, MD

Published/Updated: October 1, 2019

  1. The Title Bar

    The title bar is color-coded with our overall recommendation.

    • Green: Benefits outweigh risks.
    • Yellow: Unclear risk/benefit profile.
    • Red: Benefits do not outweigh risks.
    • Black: Obvious harms, no clear benefits.
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