Comparison of periglottic oxygen fraction, tracheal oxygen fraction and safe apnea time under different apneic...

Apneic oxygenation prolongs safe apnea time and reduces hypoxemia risk during airway management. The primary objective of this study was to compare the safe apnea time among various techniques, while the secondary objective was to evaluate intergroup differences in periglottic and tracheal oxygen fractions (FgO₂ and FtO₂).

This randomized, non-inferiority trial enrolled 125 participants, assigned to five groups: modified nasopharyngeal airway with 10 L/min oxygen (Naso group), nasal cannula oxygenation at 2 L/min (L2 group), 5 L/min (L5 group), and 10 L/min (L10 group), and a control group without supplemental oxygen (L0 group).

The success rate in the L10 group was lower than that in the Naso group (82.6% vs. 95.7%; risk difference, -13.0%; 95%CI: -27.8% to 1.7%), and non-inferiority was not established, but had similar safe apnea times (15 [15 to 15] min vs 15 [15 to 15] min, P = 0.138).The L10 group demonstrated superior performance compared to the L0, L2, and L5 groups terms of achieving a safe apnea time of 15 min (82.6% vs 0、8.7% and 43.5%,respectively; P < 0.001). At all measured time points,FgO₂ and FtO₂ in the L10 group were lower than those in the Naso group, but higher than those in the L0, L2 and L5 groups (P < 0.001). FgO₂ at the end of the apnea was positively correlated with safe apnea time.

The nasal cannula at 10 L/min, along with the modified nasopharyngeal airway, was associated with longer safe apnea times and relatively higher FgO₂ and FtO₂ levels. Higher oxygen flow rates were associated with increased FgO₂, FtO₂, and longer safe apnea duration.

The study was approved by the Ethics Committee of the Obstetrics and Gynaecology Hospital of Fudan University (2022-197) on January 9, 2023. The study was registered on ChiCTR (ChiCTR2300067642) on January 16, 2023.