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High-flow nasal oxygen: benefits are hard to show in COVID-19 patients with mild hypoxaemia
  1. Arnaud W Thille1,2,
  2. Jean-Pierre Frat1,2
  1. 1 Médecine Intensive Réanimation, Centre Hospitalier Universitaire de Poitiers, Poitiers, France
  2. 2 INSERM CIC 1402, IS-ALIVE research group, Université de Poitiers UFR Médecine et Pharmacie, Poitiers, France
  1. Correspondence to Professor Arnaud W Thille, Médecine Intensive Réanimation, Centre Hospitalier Universitaire de Poitiers, Poitiers 86000, France; aw.thille{at}

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High-flow nasal oxygen (HFNO) is widely used in intensive care units (ICUs) and now being considered as a first-line oxygenation strategy for management of patients with acute hypoxaemic respiratory failure.1 Benefits of HFNO can be explained by its physiological effects including high FiO2 delivery, low levels of positive pressure in the upper airways and ventilatory support due to dead-space wash-out, leading to decreased respiratory rate and work of breathing.2 The FLORALI trial was the seminal study, showing clinical benefits of HFNO as compared with conventional oxygen therapy (COT) or non-invasive ventilation (NIV) in patients with acute hypoxaemic respiratory failure, that is, hypoxaemia and respiratory rate above 25 breaths/minute.3 Whereas the risk of mortality was significantly lower with HFNO as compared with COT or NIV, the risk of intubation decreased only in patients with moderate-to-severe hypoxaemia (ratio of partial pressure of arterial oxygen to fraction of inspired oxygen, PaO2/FiO2<200 mm Hg), ranging from 35% to 50%, a finding suggesting that beneficial effects are more pronounced in patients with greater respiratory severity. Consequently, clinical practice guidelines drawn up before COVID-19 pandemic suggested the use of HFNO over COT or NIV in patients with acute hypoxaemic respiratory failure, although it was only a conditional recommendation.1

In patients with COVID-19-related respiratory failure admitted in ICUs, two large-scale clinical …

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  • Contributors AWT and J-PF wrote the editorial.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests AWT and J-PF received grants, non-financial supports and personnal fees (travel expense coverage to attend scientific meetings and payments for lectures) from Fisher & Paykel.

  • Provenance and peer review Commissioned; externally peer reviewed.

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