Elsevier

The Lancet

Volume 367, Issue 9517, 8–14 April 2006, Pages 1155-1163
The Lancet

Articles
Effect of non-invasive positive pressure ventilation (NIPPV) on mortality in patients with acute cardiogenic pulmonary oedema: a meta-analysis

https://doi.org/10.1016/S0140-6736(06)68506-1Get rights and content

Summary

Background

Non-invasive positive pressure ventilation (NIPPV), using continuous positive airway pressure (CPAP) or bilevel ventilation, has been shown to reduce the need for invasive mechanical ventilation in patients with acute cardiogenic pulmonary oedema. We assessed additional benefits of NIPPV in a meta-analysis.

Methods

Meta-analysis comparison in acute cardiogenic pulmonary oedema was undertaken to compare (1) CPAP with standard therapy (oxygen by face-mask, diuretics, nitrates, and other supportive care), (2) bilevel ventilation with standard therapy, and (3) bilevel ventilation with CPAP, incorporating randomised controlled trials identified by electronic and hand search (1966–May, 2005). In 23 trials that fulfilled inclusion criteria, we assessed the effect of NIPPV on hospital mortality and mechanical ventilation, estimated as relative risks.

Findings

CPAP was associated with a significantly lower mortality rate than standard therapy (relative risk 0·59, 95% CI 0·38–0·90, p=0·015). A non-significant trend towards reduced mortality was seen in the comparison between bilevel ventilation and standard therapy (0·63, 0·37–1·10, p=0·11). We recorded no substantial difference in mortality risk between bilevel ventilation and CPAP (p=0·38). The need for mechanical ventilation was reduced with CPAP (0·44, 0·29–0·66, p=0·0003) and with bilevel ventilation (0·50, 0·27–0·90, p=0·02), compared with standard therapy; but no significant difference was seen between CPAP and bilevel ventilation (p=0·86). Weak evidence of an increase in the incidence of new myocardial infarction with bilevel ventilation versus CPAP was recorded (1·49, 0·92–2·42, p=0·11). Heterogeneity of treatment effects was not evident for mortality or mechanical ventilation across patients' groups.

Interpretation

In patients with acute cardiogenic pulmonary oedema, CPAP and bilevel ventilation reduces the need for subsequent mechanical ventilation. Compared with standard therapy, CPAP reduces mortality; our results also suggest a trend towards reduced mortality after bilevel NIPPV.

Introduction

In the past two decades, non-invasive respiratory support has received a great deal of interest in the management of patients presenting with acute cardiogenic pulmonary oedema. This non-invasive respiratory support has been provided either by continuous positive airway pressure (CPAP) or by bilevel ventilation (both inspiratory and expiratory support), which are often collectively termed as non-invasive positive pressure ventilation (NIPPV). Although CPAP is not a true ventilatory mode, it is often referred to as NIPPV. The physiological effects of CPAP include augmentation of cardiac output and oxygen delivery,1 improved functional residual capacity and respiratory mechanics, reduced effort in breathing,2 and decreased left ventricular afterload.3, 4

The combination of inspiratory assistance with expiratory positive airway pressure (EPAP) has been argued to reduce the work of breathing and to alleviate respiratory distress more effectively than CPAP alone. Physiological studies in acute cardiogenic pulmonary oedema have shown that bilevel ventilation to be more effective at unloading the respiratory muscles than CPAP.5 However, enthusiasm for bilevel ventilation in acute cardiogenic pulmonary oedema was reduced after adverse effects were recorded by Mehta and colleagues.6 These adverse effects included a higher myocardial infarction rate with bilevel ventilation than that with CPAP; this difference occurred despite more rapid reductions in arterial carbon dioxide tension (PaCO2) with bilevel ventilation than with CPAP.

Thus, the best respiratory support for treatment of an episode of acute respiratory failure due to acute cardiogenic pulmonary oedema remains unclear. The British Thoracic Society guidelines7 recommend the use of CPAP in patients who still have hypoxia despite the best medical treatment, and reserve the use of bilevel ventilation for patients in whom CPAP is unsuccessful. Subsequent to the first meta-analysis on this subject,8 several published randomised controlled trials have shown the benefits of CPAP and bilevel ventilation in reducing the need for mechanical ventilation in patients with acute cardiogenic pulmonary oedema. This meta-analysis was undertaken to assess and compare the benefits of CPAP and bilevel ventilation beyond a reduction in mechanical ventilation needs to other clinically relevant endpoints in patients with acute cardiogenic pulmonary oedema, such as mortality and length of hospital stay.

Section snippets

Trial selection

Randomised trials on acute cardiogenic pulmonary oedema in human beings that compared CPAP or bilevel ventilation with standard therapy (oxygen by facemask, diuretics, nitrates, and other supportive care) or CPAP with bilevel ventilation were considered for inclusion. Only trials reporting hospital mortality or the need for invasive mechanical ventilation were included. We excluded studies reporting only physiological endpoints (improvements in gas exchange) and descriptive studies. Our search

Results

Of the 43 160 articles on respiratory failure or insufficiency that were screened, one investigator (JVP) reviewed abstracts of the 1354 articles pertaining to respiratory support in acute cardiogenic pulmonary oedema, and three investigators (JVP, JLM, ADB) reviewed 110 articles for further assessment (table 1). 23 articles fulfilled criteria for inclusion, including three abstracts. 12 studies compared CPAP with standard therapy,21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32 seven compared

Discussion

This systematic review has shown the benefit of NIPPV in the management of patients presenting with acute cardiogenic pulmonary oedema. A significant reduction in the need for invasive mechanical ventilation was seen with both CPAP and bilevel ventilation compared with standard therapy. The mortality benefit of NIPPV reached significance for CPAP (vs standard therapy) and tended towards significance for bilevel ventilation versus standard therapy. Mortality did not differ significantly between

References (52)

  • CH Schmid et al.

    Meta-regression detected associations between heterogeneous treatment effects and study-level, but not patient-level, factors

    J Clin Epidemiol

    (2004)
  • F Lenique et al.

    Ventilatory and hemodynamic effects of continuous positive airway pressure in left heart failure

    Am J Respir Crit Care Med

    (1997)
  • Noninvansive positive pressure ventilation in acute respiratory failure

    Am J Respir Crit Care Med

    (2001)
  • S Mehta et al.

    Noninvasive ventilation

    Am J Respir Crit Care Med

    (2001)
  • K Chadda et al.

    Cardiac and respiratory effects of continuous positive airway pressure and noninvasive ventilation in acute cardiac pulmonary edema

    Crit Care Med

    (2002)
  • S Mehta et al.

    Randomized, prospective trial of bilevel versus continuous positive airway pressure in acute pulmonary edema

    Crit Care Med

    (1997)
  • Non-invasive ventilation in acute respiratory failure

    Thorax

    (2002)
  • SP Keenan et al.

    Which patients with acute exacerbation of chronic obstructive pulmonary disease benefit from noninvasive positive-pressure ventilation? A systematic review of the literature

    Ann Intern Med

    (2003)
  • JV Peter et al.

    Noninvasive ventilation in exacerbations of chronic obstructive pulmonary disease: implications of different meta-analytic strategies

    Ann Intern Med

    (2004)
  • MJ Bradburn et al.

    Metan-sbe24 an alternative meta-analysis command

    Stata Technical Bulletin Reprints

    (1998)
  • JP Higgins et al.

    Quantifying heterogeneity in a meta-analysis

    Stat Med

    (2002)
  • SJ Sharp

    metareg, sbe23: Meta-analysis regression

    Stata Technical Bulletin Reprints

    (1998)
  • AD Bersten

    Noninvasive ventilation for cardiogenic pulmonary edema: froth and bubbles?

    Am J Respir Crit Care Med

    (2003)
  • T Steichen

    Tests for publication bias in meta-analysis

    Stata Technical Bulletin Reprints

    (1998)
  • S Duval et al.

    A nonparametric “trim and fill” method of accounting for publication bias in meta-analysis

    J Am Stat Soc

    (2000)
  • J Lau et al.

    Cumulative meta-analysis of therapeutic trials for myocardial infarction

    N Engl J Med

    (1992)
  • Cited by (0)

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