Relevant studies for nasal high flow (NHF) in patients with acute respiratory failure
| Design | Patients | Results | |
| Benefit | |||
| Lenglet et al. [19] | Prospective, observational study | 17 ARF patients on oxygen with a non-rebreathing face mask who switched to NHF | NHF was associated with a significant decrease in dyspnoea, respiratory rate and a significant increase in SpO2 within the first 15 min of its application |
| Roca et al. [22] | Prospective, comparative study of sequential interventions | 20 patients with hypoxaemic ARF received oxygen via face mask and NHF for 30 min each | NHF was associated with less dyspnoea and mouth dryness and more comfort than face mask; it was also associated with higher PaO2 and lower respiratory rate, with no differences in PaCO2 |
| Sztrymf et al. [23] | Prospective observational study | 38 ICU patients with ARF who received oxygen through NHF | NHF was associated with a significant reduction in respiratory rate, heart rate, dyspnoea score, supraclavicular retraction and thoraco-abdominal asynchrony and a significant improvement in SpO2 |
| Sztrymf et al. [24] | Prospective observational study | 20 patients with persistent ARF who received oxygen through NHF | Use of NHF enabled a significant reduction of respiratory rate and a significant increase in oxygen saturation and PaO2 |
| Frat et al. [26] | Multicentre, open-label RCT | 310 ARF patients admitted to ICU, randomly assigned to NHF, SOT or NIV | ICU and 90-day mortality were significantly lower with NHF compared with SOT or NIV, although no significant difference in intubation rate was found between the three study groups. In the subgroup of patients with PaO2/FiO2 ≤200 the intubation rate was significantly lower with NHF |
| Messika et al. [27] | Prospective observational study | Effectiveness and frequency of NHF use in patients with ARDS | 29% of patients requiring noninvasive ventilatory support were treated via NHF as first-line treatment. Among them, the intubation rate was 40%. Haemodynamic failure was associated with NHF failure and intubation |
| No benefit | |||
| Jones et al. [31] | Pragmatic open randomised controlled trial | 303 ARF patients at emergency departments randomised to NHF or SOT | There was no difference between the groups in NIV or intubation rate during the emergency department stay in mortality, on emergency department and hospital length of stay |
ARF: acute respiratory failure; SpO2: arterial oxygen saturation measured by pulse oximetry; PaO2: arterial oxygen tension; PaCO2: arterial carbon dioxide tension; ICU: intensive care unit; SOT: standard oxygen treatment; NIV: noninvasive ventilation; FiO2: inspiratory oxygen fraction; ARDS: acute respiratory distress syndrome.