Fig. 1From: External validation of the HACOR score and ROX index for predicting treatment failure in patients with coronavirus disease 2019 pneumonia managed on high-flow nasal cannula therapy: a multicenter retrospective observational study in JapanFlow diagram of the study participant selection process. To achieve this enrollment, we set the research period from January 16, 2020, to March 31, 2022. Upon collecting cases during this period, the actual enrollment reached 300 participants. DNI: do-not-intubateBack to article page