Respiratory Support in the Emergency Department: An Updated Systematic Review and Meta-Analysis

An estimated 20% of emergency department (ED) patients require respiratory support (RS). Evidence suggests that nasal high flow (NHF) reduces RS need.

This is an update of a published review comparing NHF to non-invasive ventilation (NIV) or to conventional oxygen therapy (COT) in adult ED patients.

This updated systematic review (SR) and meta-analysis (MA) methods reflect the Cochrane Collaboration's methodology. The search of six databases was first completed in July 2023 and then repeated in November 2025. Databases were searched for randomized controlled trials (RCTs) comparing NHF to COT or NIV in the ED. Three summary estimates were reported: (1) need to escalate care, (2) mortality, and (3) adverse events (AEs).

The updated search identified three new studies, bringing the total to 21 eligible RCTs (n = 2158). One of the six MA conclusions was statistically significant. Compared with COT, NHF showed no SS difference in the risk of escalation (RR 0.65; 95% CI [0.41, 1.04]; p = 0.07), mortality (RR 1.05; 95% CI [0.74, 1.51]; p = 0.77), and AE (RR was 0.98; 95% CI [0.6, 1.6]; p = 0.94) outcomes were found. Compared with NIV, NHF increased the risk of escalation by 86% (RR 1.86; 95% CI [1.26, 2.75]; p = 0.001), but mortality risk was not SS (RR 1.33; 95% CI [0.86, 2.06]; p = 0.20).

Evidence suggests NHF therapy may be an alternative to COT in managing RS in EDs. While NHF may not be as effective as NIV at preventing escalation, it does not increase mortality risk, offering a nuanced approach to RS tailored to patient-specific needs. This evidence-informed decision-making can enhance patient outcomes. However, further research is needed, especially given the COVID-19 pandemic's impact on ED research.