Effect of high flow nasal cannula oxygenation on incidence of hypoxia during sedated gastrointestinal endoscopy in patients with obesity: multicentre randomised controlled trial.

Objective: To determine whether high flow nasal cannula (HFNC) oxygenation can reduce the incidence of hypoxia during sedated gastrointestinal endoscopy in patients with obesity.

Design: Multicentre, randomised, parallel group trial.

Setting: Three tertiary hospitals in Shanghai, China.

Participants: 1000 adult patients with obesity (body mass index ≥28) who were scheduled for gastrointestinal endoscopy.

Interventions: Participants were randomly allocated to receive regular nasal cannula oxygenation or HFNC oxygenation during a sedated procedure with propofol and low dose sufentanil.

Main Outcome Measures: The primary outcome was the incidence of hypoxia (75%≤SpO<90% for <60 s) during the procedure. Secondary outcomes included the incidences of subclinical respiratory depression (90%≤SpO<95% for any duration) and severe hypoxia (SpO<75% for any duration or 75%≤SPO<90% for >60 s) during the procedure.

Results: From 6 May 2021 to 26 May 2023, 984 patients (mean age 49.2 years; 36.9% (n=363) female) completed the study and were analysed. Compared with regular nasal cannula oxygenation, HFNC oxygenation reduced the incidence of hypoxia from 21.2% (103/487) to 2.0% (10/497) (difference -19.14, 95% confidence interval -23.09 to -15.36; P<0.001), subclinical respiratory depression from 36.3% (177/487) to 5.6% (28/497) (difference -30.71, -35.40 to -25.92; P<0.001), and severe hypoxia from 4.1% (20/487) to 0% (0/497) (difference -4.11%, -6.26 to -2.48; P<0.001). Other sedation related adverse events did not differ between the two groups.

Conclusions: In patients with obesity, oxygenation via HFNC during sedated gastrointestinal endoscopy significantly reduced the incidences of hypoxia, subclinical respiratory depression, and severe hypoxia without increasing other adverse events.

Trial Registration: ClinicalTrials.gov NCT04500392.