High-flow nasal oxygen versus conventional nasal cannula for gastroscopy with sedation in elderly patients at high altitudes: a partially-blinded randomized controlled trial in Tibet, China

In high-altitude environments with hypobaric hypoxia, chronic hypoxia can affect organs. This study aimed to determine whether high-flow nasal oxygen (HFNO) can reduce the incidence of hypoxemia in elderly patients undergoing gastroscopy with sedation at high altitudes. This single-center, partially-blinded, prospective randomized trial was conducted in Shigatse, Tibet, China (3800 m above sea level). Elderly patients aged ≥ 60 undergoing gastroscopy with sedation were randomly assigned to either the HFNO group (60 L per minute, 100% oxygen) or the conventional nasal cannula (CNC) group (6 L per minute). The primary endpoint was the incidence of hypoxemia, defined as pulse SpO2 < 90% for > 10 s during sedation. The incidence of hypoxemia was significantly lower in the HFNO group than the CNC group (2.8% vs. 32.9%, risk ratio (RR): 0.691; 95% confidence interval (CI): 0.584–0.818, p < 0.001). The median SpO2 after pre-oxygenation was similar between the groups (97.0% [96.0–98.0] vs. 96.0% [95.0–98.0], p = 0.053). However, the median minimum SpO2 during the procedure was significantly higher in the HFNO group compared to the CNC group (96% [95–98] vs. 93% [87–96], p < 0.001). The median duration of hypoxemia and the number of hypoxemia episodes were 0.0 s (0.0–22.0) and 0 (0–1), respectively. In contrast, the values were 0.0 s (0.0–0.0) and 0 (0–0) in the HFNO group (p < 0.001). The median recovery time was shorter in the HFNO group compared to the CNC group (1.0 min [0.5–1.5] vs. 1.5 min [1.0-2.5], p = 0.003). Compared to CNC, HFNO significantly reduced the incidence of hypoxemia during gastroscopy with sedation in elderly patients at high altitudes. ChiCTR2400085110; registered on 31 May 2024. ∙ Research Question: Does HFNO, compared to CNC, reduce the incidence of hypoxemia in elderly patients undergoing gastroscopy with sedation at high altitudes? ∙ Findings: HFNO significantly reduced the incidence of hypoxemia during gastroscopy with sedation in elderly patients at high altitudes compared to CNC. ∙ Meaning: HFNO may be a more effective method than CNC for preventing hypoxemia during gastroscopy with sedation in elderly patients at high altitudes.