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

Abstract 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 2 <90% for <60 s) during the procedure. Secondary outcomes included the incidences of subclinical respiratory depression (90%≤SpO 2 <95% for any duration) and severe hypoxia (SpO 2 <75% for any duration or 75%≤SPO 2 <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 .