The Effect of Positive Pressure Airway Support on Mortality and the Need for Intubation in Cardiogenic Pulmonary Edema A Systematic Review

OBJECTIVE: To critically appraise and summarize the trials examining the addition of continuous positive airway pressure (CPAP) or noninvasive positive pressure ventilation (NPPV) to standard therapy on hospital mortality, need for endotracheal intubation, and predischarge left ventricular function in patients admitted to the hospital with cardiogenic pulmonary edema with gas exchange abnormalities. DATA SOURCES: We searched MEDLINE (1983 to June 1997) and bibliographies of all selected articles and review articles. We also reviewed the abstracts from the proceedings of relevant meetings from 1985 to 1997. STUDY SELECTION: (1) POPULATION: patients presenting to hospital with cardiogenic pulmonary edema; (2) intervention: one of the following three: (a) the use of CPAP and standard medical therapy vs standard medical therapy alone; (b) the use of NPPV and standard medical therapy vs standard medical therapy alone; and (c) the use of NPPV and standard therapy vs CPAP and standard therapy; (3) outcome: hospital survival, need for endotracheal intubation, or predischarge left ventricular dysfunction; and (4) study design: randomized controlled trial (RCT); if there were fewer than two RCTs, other study designs were included. DATA EXTRACTION: Two authors independently extracted data and evaluated the methodologic quality of the studies. DATA SYNTHESIS: CPAP was associated with a decrease in need for intubation (risk difference, -26%, 95% confidence intervals, -13 to -38%) and a trend to a decrease in hospital mortality (risk difference, -6.6%; +3 to -16%) compared with standard therapy alone. There was insufficient evidence to comment on the effectiveness of NPPV either compared with standard therapy or CPAP and standard therapy. Evidence was also lacking on the potential for either intervention to cause harm. CONCLUSIONS: A modest amount of favorable experimental evidence exists to support the use of CPAP in patients with cardiogenic pulmonary edema. CPAP appears to decrease intubation rates and data suggest a trend toward a decrease in mortality, although the potential for harm has not been excluded. The role of NPPV in this setting requires further study before it can be widely recommended.