Background: High-flow nasal cannula oxygen therapy (HFNC) is widely used mainly in the acute care setting, but limited data are available on real-world practice in adults. The objective of this study was to describe HFNC practices in Japanese adults. Methods: A retrospective cross-sectional multicenter survey of adult patients receiving HFNC from January through March 2015 was conducted in 33 participating hospitals in Japan. Results: We obtained information on 321 patients (median age, 76
218 men, 103 women
median estimated PaO2/FIO2 178 mm Hg) from 22 hospitals. Do-not-intubate status was determined in 37.4% of patients. Prior to HFNC, 57.9% of patients received conventional oxygen therapy
25.9%, noninvasive ventilation
and 15.0%, invasive mechanical ventilation. The common indications for HFNC were acute hypoxemic respiratory failure (ARF) (65.4%), postoperative respiratory support (15.9%), and post-extubation respiratory support (11.2%). The underlying etiology of ARF included interstitial lung disease, pneumonia, and cardiogenic pulmonary edema. HFNC was administered mostly in intensive care units or intermittent care units (60.7%) and general wards (36.1%). Median duration of HFNC was 4 days
median total flow rate, 40 L/min
and median FIO2, 50%. HFNC significantly improved PaO2, PaCO2, SpO2 and respiratory rate from baseline. Two-thirds of patients finally survived to be discharged or transferred. Conclusions: We documented patient demographics, clinical indications, and settings of HFNC use in the real world. We also demonstrated positive effects of HFNC on respiratory parameters. Further studies are urgently needed regarding the efficacy and safety of HFNC in populations outside of previous clinical trials.