Effect of out-of-hospital noninvasive positive-pressure support ventilation in adult patients with severe respiratory distress: a systematic review and meta-analysis.

STUDY OBJECTIVE Noninvasive positive-pressure ventilation (NIPPV) is increasingly being used by emergency medical services (EMS) for treatment of patients in respiratory distress. The primary objective of this systematic review is to determine whether out-of-hospital NIPPV for treatment of adults with severe respiratory distress reduces inhospital mortality compared with "standard" therapy. Secondary objectives are to examine the need for invasive ventilation, hospital and ICU length of stay, and complications. METHODS Electronic searches of MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cumulative Index to Nursing and Allied Health Literature were conducted and reference lists of relevant articles hand searched. Randomized controlled trials comparing out-of-hospital NIPPV with standard therapy in adults (aged ≥16 years) with severe respiratory distress published in English were included. Two reviewers independently screened abstracts, assessed quality of the studies, and extracted data. Data were pooled with random-effects models and reported as risk ratios (RRs) with 95% confidence intervals (CIs) and number needed to treat (NNT). RESULTS Seven randomized controlled trials were included, with a combined total of 632 patients; 313 in the standard therapy group and 319 in the NIPPV group. In patients treated with NIPPV, the pooled estimate showed a reduction in both inhospital mortality (RR 0.58; 95% CI 0.35 to 0.95; NNT=18) and need for invasive ventilation (RR 0.37; 95% CI 0.24 to 0.58; NNT=8). There was no difference in ICU or hospital length of stay. CONCLUSION Out-of-hospital administration of NIPPV appears to be an effective therapy for adult patients with severe respiratory distress.