Studies of HHFNC versus standard oxygen therapy in adult patients (>16 years) already admitted to a critical care unit and who required oxygen therapy were eligible for inclusion. The HHFNC system could be Optiflow, Aquinox, Vapotherm or PARI hydrate, all at a flow greater than 15L/min.
The primary outcome was oxygenation, as measured by partial pressure of arterial oxygenation (PaO2), oxygenation index (PaO2/FiO2) obtained via arterial blood gas (ABG) analysis and pulse oxymetry (SpO2). Secondary outcomes included, costs, mortality, non-invasive ventilation (NIV), positive airway pressure (cmH2O), reduction in work of breathing/improvements in ventilation (PaCO2), intubation rates and patient comfort and tolerance.
The included studies compared either Vapotherm or Optiflow HHFNC devices with traditional oxygen therapy in patients with burns, respiratory failure/insufficiency and post-extubation. Most patients were male (66%).
Two reviewers independently undertook study selection.