title: Effect of non-invasive positive pressure ventilation (NIPPV) on mortality in patients with acute cardiogenic pulmonary oedema: a meta-analysis.
abstract: 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.
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Intensive Care Medicine, The Queen Elizabeth Hospital, Woodville South, SA 5011, Australia.
authors.forename: John Victor
authors.initials: JV
authors.lastname: Peter
authors.forename: John L
authors.initials: JL
authors.lastname: Moran
authors.forename: Jennie
authors.initials: J
authors.lastname: Phillips-Hughes
authors.forename: Petra
authors.initials: P
authors.lastname: Graham
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Bersten
mesh_terms: D045422:Continuous Positive Airway Pressure / Q000379:methods*; D017052:Hospital Mortality; D006801:Humans; D011654:Pulmonary Edema / Q000628:therapy*; D016032:Randomized Controlled Trials as Topic; D015919:Ventilators, Negative-Pressure