Abstract: Objective To investigate the application of high-flow nasal cannula oxygen therapy (HFNC) for anesthesia induction in the elderly patients undergoing gastrointestinal surgery. Methods Eighty elderly patients undergoing elective gastrointestinal surgery were randomly equally allocated into the HFNC group and the face mask group. In the HFNC group, high-flow oxygen inhalation through the nasal catheter was performed until endotracheal intubation was completed. While in the face mask group, endotracheal intubation was achieved after pre-oxygenation and mechanical ventilation through non-invasive mask. The heart rate (HR),mean arterial pressure (MAP), pulse oxygen saturation (SpO₂), partial pressure of oxygen in artery (PaO₂) and partial pressure of carbon dioxide in artery (PaCO₂) were recorded at the time of arterial puncture completed (T0), 5 minutes after pre-oxygenation (T1), 3 minutes after cis-atracurium injection (T2), and immediately after the endotracheal intubation (T3). The apneic tracheal intubation period was defined from apnea to the completion of endotracheal intubation (T2 to T3). Results There was no significant difference in vital signs between the two groups. The level of PaO₂ was significantly higher in the HFNC group than that in the face mask group at T1 (P<0.05). During apneic tracheal intubation period, the decrease of PaO₂ and the increase of PaCO₂ in the HFNC group were significantly lower than those in the face mask group (P<0.05). The comfort level in the HFNC group was significantly higher than that in the face mask group (P<0.05). Conclusions HFNC provides effective pre-oxygenation, slight decrease of PaO₂ during apneic tracheal intubation period without CO₂ accumulation and is more comfortable for the elderly patients undergoing gastrointestinal surgery.

Key words: high-flow nasal cannula oxygen therapy, face mask, pre-oxygenation, safe apneic period