Non-invasive ventilation in the prehospital emergency setting: A systematic review and meta-analysis

Introduction: Non-invasive ventilation is a well-established treatment for acute respiratory failure, being increasingly applied in the prehospital setting. This systematic review and meta-analysis aims to investigate whether early prehospital initiation of non-invasive ventilation reduces mortality compared to standard oxygen therapy.Methods: We searched PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials from inception to February 7th, 2022, for studies comparing prehospital non-invasive ventilation performed by emergency medical services versus standard oxygen therapy in patients with acute respiratory failure. The primary outcome was mortality at the longest follow-up available.Results: We included ten randomized studies and two quasi-randomized studies for a total of 1485 patients. Prehospital treatment with non-invasive ventilation compared with standard oxygen therapy did not significantly reduce mortality at the longest follow-up available (107/810 [13%] vs 114/772 [15%]; RR =0.89; 95% CI, 0.70-1.13; P = 0.34; I2=24%). The endotracheal intubation rate was reduced when receiving prehospital non-invasive ventilation (38/776 [4.9%] vs 81/743 [11%]; RR =0.44; 95% CI, 0.31-0.63; P <0.001; I2=0%; number needed to treat 17). The intensive care admission rate (114/532 [21%] vs 129/507 [25%]; RR =0.85; 95% CI, 0.69-1.04; P = 0.11; I2=0%) and length of hospital stay (mean difference=-1.29 days; 95% CI, -3.35-0.77; P = 0.21; I2=82%) were similar between groups.Conclusions: Adults with acute respiratory failure treated in the prehospital setting managed with non-invasive ventilation had a lower risk of intubation than those managed with standard oxygen therapy, with similar risk of death, intensive care admission, and length of hospital stay.Review registration: PROSPERO CRD42021284947.