Effect of Flow Rates of High-Flow Nasal Cannula on Extubation Outcomes: A Randomized Controlled Trial.

Background: High-flow nasal cannula (HFNC) has emerged as a promising intervention for postextubation oxygen therapy, with the potential to reduce the need for reintubation. However, it remains unclear whether using a higher flow setting provides better outcomes than the commonly used flow rate of 30 to 50 L/min. Research Question: Does setting the flow rate of HFNC at 60 L/min vs 40 L/min for postextubation care result in different extubation outcomes? Study Design and Methods: This randomized controlled trial assigned intubated patients to receive HFNC at either a 60 L/min or 40 L/min flow rate following extubation. The assigned flow rate was maintained for 24 hours. The primary outcome was a composite of reintubation or the use of noninvasive ventilation (NIV) within 48 hours’ after extubation. Key secondary outcomes included ahead-of-schedule changes in HFNC settings and mortality. Results: A total of 180 patients were randomized; 169 were included in the analysis (86 in the 40 L/min group and 83 in the 60 L/min group). The primary outcome events occurred in 19 patients (22.1%) in the 40 L/min group and in 14 patients (16.9%) in the 60 L/min group (risk difference, 5.2%; 95% CI, –6.7% to 17.1%; P = .39). For secondary outcomes, the 40 L/min group was associated with a higher risk of escalation in respiratory support, defined as using NIV or up-titration of HFNC settings (24 [27.9%] vs 8 [9.6%]; P = .002). Interpretation: In unselected extubated patients, setting the HFNC flow rate at 60 L/min did not reduce the risk of reintubation or NIV use compared with a flow rate of 40 L/min. Using a flow rate of 40 L/min with as-needed up-titration may be a reasonable alternative to setting the flow at 60 L/min for postextubation care. However, this trial may not have been sufficiently powered to exclude a small between-group difference. Clinical Trial Registration: ClinicalTrials.gov; No.: NCT04934163; URL: www.clinicaltrials.gov.