Clinical Usage of High-Flow Nasal Cannula Across Disease Categories and Care Settings: A Nationwide Cohort Study in Japan

BACKGROUND: Although the use of high-flow nasal cannula (HFNC) is recommended for the management of acute hypoxemic respiratory failure and for postextubation respiratory support, the efficacy for other etiologies remains uncertain. This study aimed to examine temporal trends in HFNC utilization and describe variations in clinical practice and clinical course across diverse disease categories and care settings. METHODS: We conducted a retrospective cohort study using a nationwide in-patient database in Japan. Hospitalized subjects who received HFNC between April 2016 and March 2023 were included. Temporal trends in HFNC use were evaluated by fiscal year using the Cochran-Armitage test. Subject characteristics, disease categories, treatment location at HFNC initiation (ICU, high-dependency unit, or general ward), timing of HFNC initiation, use of invasive mechanical ventilation, and in-hospital mortality were analyzed descriptively. RESULTS: < .001). Respiratory diseases were the most common indication (37%), followed by cardiovascular diseases (23%), neonatal conditions (17%), and malignancy (10%). HFNC was frequently used in conjunction with invasive mechanical ventilation, particularly after extubation, among subjects with cardiovascular conditions and neonatal subjects. In contrast, HFNC was more often used without invasive mechanical ventilation in subjects with respiratory diseases or malignancy, frequently in general wards. Overall in-hospital mortality was 25% and varied markedly by disease category and care setting, with particularly high mortality among subjects with interstitial pneumonia or malignancy who initiated HFNC in general wards, approaching 60%. CONCLUSIONS: HFNC use increased markedly in Japan and expanded beyond ICUs into general wards. Utilization patterns and outcomes differed considerably by underlying disease and care setting, indicating heterogeneous clinical roles of HFNC across patient populations.