Efficacy of high-flow nasal oxygen in preventing hypoxia during Gastrointestinal endoscopy: a retrospective cohort study.

Background: Hypoxia is a common complication, particularly in gastrointestinal endoscopy due to respiratory depression induced by intravenous anesthesia with the use of propofol. This study aimed to investigate the efficacy and safety of high-flow nasal oxygen in preventing hypoxia during gastrointestinal endoscopy.

Methods: This single-center retrospective study included 900 patients undergoing gastrointestinal endoscopy at Renji Hospital, Shanghai Jiao Tong University School of Medicine, from June 15th 2023 to August 15th 2023. Patients were categorized into the high-flow nasal oxygen (HFNO) group using a high-flow-specific nasal cannula or the standard nasal oxygen (SNO) group using a standard nasal cannula. The primary outcome of this study was the incidence of hypoxia (mild hypoxia: 75% ≤ SpO₂ < 90% for < 60 s, severe hypoxia: SpO₂ < 75% or 75% ≤ SpO₂ < 90% for > 60 s). Secondary outcomes included the incidence of subclinical respiratory depression (90% ≤ SpO₂ < 95%) and adverse events associated with the nasal cannula. We used the propensity score matching (PSM) with a 1:1 ratio to balance the patient baseline characteristics.

Results: 884 patients were included in the analysis after PSM. The general characteristics of patients had no statistically significant difference between the two groups. The HFNO group demonstrated significantly better outcomes compared with SNO, including the lower incidence of hypoxia (0% vs. 5.66%, p < 0.001) and subclinical respiratory depression (1.36% vs. 12.67%, p < 0.001), and fewer adverse events associated with the nasal cannula (0% vs. 4.07%, p < 0.001). Furthermore, a multifactorial analysis identified body mass index (BMI) (HR = 1.43, 95% CI [1.17-1.76], p < 0.001) and sedation depth (HR = 10.31, 95% CI [3.68-28.88], p < 0.001) as risk factors for hypoxia in the SNO group.

Conclusion: HFNO emerges as a promising approach for preventing hypoxia during gastrointestinal endoscopy, offering a simple, effective, and non-invasive means of respiratory support.