High flow nasal oxygen for acute hypoxaemic respiratory failure in the intensive care unit: An umbrella review

Objectives To assess whether high flow nasal oxygen (HFNO) therapy reduces the need for endotracheal intubation in adults with acute hypoxaemic respiratory failure (AHRF) in the intensive care unit (ICU). Methods Systematic reviews were identified through a structured search of MEDLINE, EMBASE, CINAHL, Cochrane Central, and Web of Science from inception to August 2024. Two reviewers independently screened studies, extracted data, and assessed methodological quality (AMSTAR-2), risk of bias (ROBIS), and review overlap using the corrected covered area method. Results Twenty systematic reviews met inclusion criteria, comprising 331 primary trials. Methodological quality in the reviews was low to moderate, and ROBIS was high. Variability was evident in heterogeneous patient cohorts, intervention implementation, outcome assessment, and follow-up, in the context of a high degree of study overlap (26.3%) across reviews. Four trials (5 intervention arms) within reviews included ICU patients with AHRF. There was no difference in effect when comparing HFNO with noninvasive ventilation (NIV) on intubation: pooled relative risk (RR) = 0.82, 95% confidence interval (CI) = 0.58–1.16, p = 0.172, I 2 = 43.2%. Two trials demonstrated no difference in effect when comparing HFNO with conventional oxygen therapy (COT) on intubation: pooled RR=0.812, 95% CI: 0.588, 1.120, p = 0.204, I 2 = 0.0%. HFNO was associated with a 49% relative reduction in mortality when compared with NIV in two trials (RR = 0.49; 95% CI=0.310–0.787, p = 0.003, I 2 = 0.0%), indicating a clear beneficial effect of HFNO on mortality in this population. Conclusions Current reviews suggest HFNO may reduce the risk of intubation compared with COT or NIV, but the overall strength of this evidence is questionable. In practice, HFNO is often applied uniformly across highly variable patient groups, despite limited clarity regarding, which subpopulations derive the greatest benefit. These limitations underscore the need for more rigorous, well-designed trials and focused systematic reviews to guide tailored, evidence-informed use of HFNO and optimise clinical decision-making.