Shippam W, et al. - As high-flow nasal oxygen provides effective pre-oxygenation and prolong apnoeic time during intubation attempts in non-pregnant patients, researchers compared pre-oxygenation using high-flow nasal oxygen (30–70 l.min⁻¹ oxygen flow) via nasal prongs with standard 15 l.min⁻¹ oxygen breathing via a tight-fitting facemask. They randomly allocated 40 healthy parturients to these two groups, and furthermore. Each patient underwent the selected pre-oxygenation method with both 3-min tidal volume breathing and 30s tidal breathing followed by eight vital capacity breaths. High-flow nasal oxygen did not reliably achieve a mean end-tidal oxygen concentration ≥ 90% compared with the standard flow rate facemask. This indicates the worse performance of high-flow nasal oxygen pre-oxygenation than standard flow rate facemask pre-oxygenation in healthy term parturients.