During the coronavirus disease 2019 (COVID-19) pandemic, oxygen support management for critically ill patients with acute hypoxemic respiratory failure (AHRF) was a key component of clinical decisionmaking. 1 There is a lack of knowledge regarding the use of high-flow nasal cannula (HFNC) in COVID-19 patients with AHRF. Most hospitals adopted an early-intubation strategy leading to a high intubation rate and the demand for intensive care unit (ICU)-beds overwhelmed hospital resources. With a low ICU bed-to-population ratio in our area, we adopted a large high-flow nasal cannula (HFNC) therapy use in COVID-19 patient-related AHRF. Here, we assessed, retrospectively, the benefit of HFNC use in this population. | METHODSForty-two COVID-19-confirmed patients with AHRF treated with at least 2 hours of HFNC in first line were included in the study between March 1 and May 23, 2020 (Figure 1). The study was declared at European General Data Protection Regulation (Identifier RMR004-25052020). Inclusion criteria were laboratory-confirmed COVID-19 patients over 18 years of age suffering from AHRF treated with HFNC as first-line therapy and admitted to the medical ICU of the Reims University Hospital. Exclusion criteria were under 18 years of age, urgent need to intubate (less than 2 hours after HFNC initiation), previous intubation in the same hospital stay, and presence of a do-not-resuscitate order.HFNC was initiated with a minimum flow of 50 L/min with a FiO 2 of 50%. Then, FiO 2 was titrated targeting an SpO 2 above 92%, and flow rate was adjusted up to 60 L/min or according to the maximum tolerated dose. HFNC failure was defined as the subsequent need for invasive mechanical ventilation. Intubation criteria were left at the discretion of physicians. Respiratory parameters were measured under HFNC conditions. The ROX index was defined as the ratio of SpO 2 /FiO 2 (%) to respiratory rate (breaths/min). In patients with AHRF treated with HFNC, a ROX index higher than 4.88 measured after 12 hours of HFNC was significantly associated with a lower risk of intubation. 2,3 Quantitative parameters were analyzed with nonparametric tests.Differences in categorical variables were assessed with chi-square. All tests were two-sided with a 5% significance level. | RESULTSResults are displayed in Table 1. Twenty-two patients were treated successfully with HFNC (52%) and twenty patients subsequently required IMV support (48%).At ICU admission, patients had a median PaO 2 /FiO 2 ratio of 128 for HFNC success group and 121.5 [88.5-135.5] for