Hands-free induction of general anesthesia: a randomised pilot study comparing usual care and high-flow nasal oxygen.

Background: The induction of general anesthesia is preceded by face mask preoxygenation and oxygen delivery during intubation (peroxygenation). High-flow nasal oxygen (HFNO) may be an effective alternative.

Methods: In this multicenter randomized controlled study, adults undergoing general anesthesia with oral intubation were included, provided written consent, and were assigned to the control group (face mask) or experimental group (HFNO). The primary objective was to validate HFNO as a safe and efficient technique for preoxygenation and peroxygenation. The main outcome was the risk of oxygen desaturation (SpO2≤92%). Analysis was performed with the intention-to-treat principle.

Results: Among 68 eligible patients, 61 completed the study (31 in the face mask group and 30 in the HFNO group). The patient characteristics were comparable between groups. A decrease in SpO2 was observed in the HFNO group (P=0.491). Oesophageal intubation at the first attempt occurred twice in the HFNO group, with no oxygen desaturation, and never occurred in the face mask group (P=0.238). There was no difference in airway management or hemodynamic recordings between the groups. The end-tidal CO2 levels at intubation were similar between the groups: 5.1 (4.7-5.7) kPa in the face mask group vs. 5.2 (4.8-6.0) kPa in the HFNO group (P=0.292). HFNO was preferred by the investigators (P=0.003) and patients, with improved comfort (P=0.018), less submandibular pain (P=0.003), and a similar severity of hoarseness (P=0.686).

Conclusions: HFNO provides a hands-free induction of general anesthesia and yields adequate preoxygenation and peroxygenation, with a significant improvement in the quality of care.