On the Shoulders of Giants
But does it save lives?
We know non-invasive ventilation for acute pulmonary edema reduces intubation rates, but does it reduce mortality? Maybe. This meta-analysis of 15 studies found that it reduced mortality in these patients. CPAP cut mortality by 45%. Bilevel non-invasive pressure support ventilation (aka BiPAP) had a trend to mortality reduction, though it was not statistically significant, and included fewer studies. CPAP and BiPAP reduced the need for intubation. There was no significant difference in CPAP and BiPAP as far as clinical outcomes, though there was far more evidence for CPAP.
Not so fast
Bear in mind the 3CPO RCT published in NEJM in 2008 found no reduction in short term mortality, though it did decrease respiratory distress. It also had a "golden" trial name! They comment on the discrepancy between this meta-analysis and the RCT's negative study outcome regarding mortality, "There is concern about reporting, publication, and recruitment bias in individual published studies that will be compounded by pooled analyses. The discrepancy between the results of our large, randomized, controlled trial and previous pooled data is not unique, and the limitations of meta-analyses have been well documented."
Non-invasive ventilation makes a big impact on patients with acute pulmonary edema - fewer need intubation, and it may reduce mortality.
- Life in the Fast Lane has a great primer on noninvasive ventilation.
- Scott Weingart's first EMCrit podcast was on the crashing pulmonary edema patient.
Noninvasive ventilation in acute cardiogenic pulmonary edema: systematic review and meta-analysis. JAMA. 2005 Dec 28;294(24):3124-30.