Meta-analysis: Noninvasive Ventilation in Acute Cardiogenic Pulmonary Edema

Background: Noninvasive ventilation (NIV) is commonly used to treat patients with acute cardiogenic pulmonary edema (ACPE), but the findings of a recent large clinical trial suggest that NIV may be less effective for ACPE than previously thought. Purpose: To provide an estimate of the effect of NIV on clinical outcomes in patients with ACPE that incorporates recent trial evidence and explore ways to interpret that evidence in the context of preceding evidence that favors NIV. Data Sources: PubMed and EMBASE from 1966 to December 2009, Cochrane Central Register of Controlled Trials and conference proceedings through December 2009, and reference lists, without language restriction. Study Selection: Randomized trials that compared continuous positive airway pressure and bilevel ventilation with standard therapy or each other. Data Extraction: Two independent reviewers extracted data. Outcomes examined were mortality, intubation rate, and incidence of new myocardial infarction (MI). Data Synthesis: Compared with standard therapy, continuous positive airway pressure reduced mortality (relative risk [RR], 0.64 [95% CI, 0.44 to 0.92]) and need for intubation (RR, 0.44 [CI, 0.32 to 0.60]) but not incidence of new MI (RR, 1.07 [CI, 0.84 to 1.37]). The effect was more prominent in trials in which myocardial ischemia or infarction caused ACPE in higher proportions of patients (RR, 0.92 [CI, 0.76 to 1.10] when 10% of patients had ischemia or MI vs. 0.43 [CI, 0.17 to 1.07] when 50% had ischemia or MI). Bilevel ventilation reduced the need for intubation (RR, 0.54 [CI, 0.33 to 0.86]) but did not reduce mortality or new MI. No differences were detected between continuous positive airway pressure and bilevel ventilation on any clinical outcomes for which they were directly compared. Limitations: The quality of the evidence base was limited. Definitions, cause, and severity of ACPE differed among the trials, as did patient characteristics and clinical settings. Conclusion: Although a recent large trial contradicts results from previous studies, the evidence in aggregate still supports the use of NIV for patients with ACPE. Continuous positive airway pressure reduces mortality more in patients with ACPE secondary to acute myocardial ischemia or infarction.