Noninvasive ventilation in acute cardiogenic pulmonary edema: systematic review and meta-analysis.

CONTEXT: In patients with acute cardiogenic pulmonary edema noninvasive ventilation may reduce intubation rate, but the impact on mortality and the superiority of one technique over another have not been clearly established.

OBJECTIVE: To systematically review and quantitatively synthesize the short-term effect of noninvasive ventilation on major clinical outcomes.

DATA SOURCES: MEDLINE and EMBASE (from inception to October 2005) and Cochrane databases (library issue 4, 2005) were searched to identify relevant randomized controlled trials and systematic reviews published from January 1, 1988, to October 31, 2005.

STUDY SELECTION AND DATA EXTRACTION: Included trials were all parallel studies comparing noninvasive ventilation to conventional oxygen therapy in patients with acute pulmonary edema. Comparisons of different techniques, either continuous positive airway pressure (CPAP) or bilevel noninvasive pressure support ventilation (NIPSV), were also included.

DATA SYNTHESIS: Fifteen trials were selected. Overall, noninvasive ventilation significantly reduced the mortality rate by nearly 45% compared with conventional therapy (risk ratio [RR], 0.55; 95% confidence interval [CI], 0.40-0.78; P = .72 for heterogeneity). The results were significant for CPAP (RR, 0.53; 95% CI, 0.35-0.81; P = .44 for heterogeneity) but not for NIPSV (RR, 0.60; 95% CI, 0.34-1.05; P = .76 for heterogeneity), although there were fewer studies in the latter. Both modalities showed a significant decrease in the "need to intubate" rate compared with conventional therapy: CPAP (RR, 0.40; 95% CI, 0.27-0.58; P = .21 for heterogeneity), NIPSV (RR, 0.48; 95% CI, 0.30-0.76; P = .24 for heterogeneity), and together (RR, 0.43; 95% CI, 0.32-0.57; P = .20 for heterogeneity). There were no differences in intubation or mortality rates in the analysis of studies comparing the 2 techniques.

CONCLUSIONS: Noninvasive ventilation reduces the need for intubation and mortality in patients with acute cardiogenic pulmonary edema. Although the level of evidence is higher for CPAP, there are no significant differences in clinical outcomes when comparing CPAP vs NIPSV.