ABSTRACT
Background This systematic review aims to summarise the evidence regarding any benefits of high flow nasal oxygen (HFNO) therapy compared to conventional oxygen therapy (COT) in hospitalised patients with acute or chronic respiratory illnesses.Methods A comprehensive search was performed across three databases for studies that reported any of: escalation to invasive mechanical ventilation (IMV), mortality, length of stay, carbon dioxide levels, disability, or admission rates.Results In patients with acute respiratory illnesses, pooled RCT data revealed no significant differences between HFNO and COT in overall need for IMV (RR = 0.82, 95% CI = 0.65–1.05; p = 0.11; n = 15 RCTs) or in-hospital mortality (RR = 1.00, 95% CI 0.85–1.17; p = 1.00; n = 5). Similarly, for patients with chronic respiratory illnesses, RCT data revealed no significant difference in overall need for IMV (RR = 0.86, 95% CI = 0.33–2.23; p = 0.76; n = 4) or in-hospital mortality (RR = 0.40, 95% CI = 0.04–4.10; p = 0.44; n = 1) for HFNO compared to COT. Patients with COVID-19 receiving HFNO had a significantly reduced need for IMV (RR = 0.72, 95% CI = 0.63–0.82; p < 0.001), short-term mortality (RR = 0.62, 95% CI = 0.48–0.79; p < 0.001), and long-term mortality (RR = 0.67, 95% CI = 0.48–0.92; p = 0.01).Conclusion HFNO did not significantly reduce the need for IMV escalation or in-hospital mortality in patients with acute or chronic respiratory illnesses, except for patients with COVID-19.