Weaning Strategies for High-Flow Nasal Cannula in Critically Ill Adults: A Randomized Clinical Trial

OBJECTIVES: This study evaluated the efficacy of different high-flow nasal cannula (HFNC) weaning protocols in critically ill adults. DESIGN: This multicenter, randomized controlled trial was conducted from December 1, 2022, to August 31, 2024, based on the suggested protocol (SLOWH trial). Experts reviewed the trial between October 2, 2024, and April 15, 2025. SETTING: Randomization was performed by a research coordinator using a sequence of random numbers generated by an independent statistician blinded to both researchers and participants. PATIENTS: Adults (≥ 18 yr old) in the ICU who met the weaning criteria after receiving HFNC were included. Among 102 patients from three tertiary care hospitals, 15 were excluded. INTERVENTIONS: The remaining patients were randomized into three intervention groups: flow reduction (FR) first, Fio2 reduction (OR) first, or simultaneous reduction (SR). The primary outcome was the HFNC weaning success rate, defined as successful transition to conventional oxygen therapy without the need for HFNC reapplication, noninvasive ventilation, or endotracheal intubation within 24 hours. MEASUREMENTS AND MAIN RESULTS: A total of 87 adults completed the trial (FR, n = 31 [male, 52%]; OR, n = 26 [male, 77%]; SR, n = 30 [male, 53%]). The weaning success rates in the FR, OR, and SR groups were 94%, 81%, and 77%, respectively (p = 0.15). The median [interquartile range] weaning duration was 31.0 hours (29.0-45.8 hr), 29.5 hours (28.0-60.4 hr), and 29.5 hours (26.5-45.0 hr) in the FR, OR, and SR groups, respectively, with no statistically significant difference among groups (p = 0.87). CONCLUSIONS: In this randomized trial, no statistically significant differences were observed among the three HFNC weaning strategies in terms of weaning success or duration.