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 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.
Competing Interests: Competing interests: All authors have completed the ICMJE uniform disclosure form at https://www.icmje.org/disclosure-of-interest/ and declare: support from the National Natural Science Foundation of China, Shanghai Municipal Science and Technology Commission Founding, Renji Hospital Clinical Innovation Foundation, Shanghai municipal Education Commission-Gaofeng Clinical Medicine Support, Shanghai Shenkang Founding, Shanghai Municipal Health Commission Key Support Project, Key Specialty Construction Project of Pudong Health and Family Planning Commission of Shanghai, Shanghai Municipal Key Clinical Specialty, and Shanghai Engineering Research Center of Peri-operative Organ Support and Function Preservation; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years; and no other relationships or activities that could appear to have influenced the submitted work.
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