High flow nasal cannula versus conventional oxygen therapy during bronchoscopy: A systematic review and individual participant data meta-analysis

BACKGROUND: High-flow nasal cannula (HFNC) is superior to conventional oxygen therapy (COT) in preventing hypoxaemia during bronchoscopy. However, factors associated with HFNC effectiveness remain unclear. We performed an individual participant data meta-analysis (IPD-MA) to identify treatment modifiers for HFNC during bronchoscopy. METHODS: We systematically reviewed randomised controlled trials (RCTs) comparing HFNC and COT during bronchoscopy in adults (January 2000-September 2025) and requested IPD from corresponding investigators. The primary outcome was desaturation during bronchoscopy. Conventional meta-analysis was performed using random-effect model; one-stage regression model was used for IPD-MA. Results were reported as odds ratios (ORs) or mean difference and 95% confidence intervals (CIs). RESULTS: Seventeen RCTs (3,116 patients: 1680 HFNC, 1436 COT) were included. Compared to COT, HFNC significantly reduced desaturation (OR 0.23, 95% CI 0.15-0.34), procedure interruption (OR 0.36, 95% CI 0.20-0.67), respiratory support escalation (OR 0.25, 95% CI 0.11-0.55), and airway intervention (OR 0.19, 95% CI 0.10-0.36) during bronchoscopy. IPD was obtained from six RCTs (1,344 patients). Significant interactions were observed between treatment effect and body mass index, baseline respiratory and heart rates, with greater relative benefit at lower values. HFNC flows ≥45 L/min were associated with reduced desaturation risk (OR 0.28, 95% CI 0.12-0.65). CONCLUSIONS: HFNC is superior to COT in reducing desaturation and procedure-related interruptions during bronchoscopy. Exploratory analyses suggest greater relative benefits in patients with lower body mass index and lower baseline respiratory and heart rates. HFNC flows ≥45 L/min furtherreduce desaturation risk. Further studies are needed in higher-risk patients. TRIAL REGISTRATION: International Prospective Register of Systematic Reviews; No.:CRD420251008924; URL: https://www.crd.york.ac.uk/prospero/.