Role of modified nasopharyngeal oxygen therapy in apnoeic oxygenation under general anaesthesia: A single-centre, randomized controlled clinical study

Apnoeic oxygenation is particularly important for patients who cannot be intubated/oxygenate after anaesthesia induction. We aimed to compare safe apnoea times between patients receiving modified nasopharyngeal oxygen therapy and those receiving high-flow nasal oxygen therapy (HFNO) following the induction of general anaesthesia.This was a single-centre, randomized controlled clinical study. Eighty-four female patients undergoing elective laparoscopic gynaecological surgery under general anaesthesia were randomly assigned to the high-flow nasal oxygen therapy group or the modified nasopharyngeal oxygen therapy group. A Kaplan–Meier survival curve was used to describe the apnoeic oxygenation time.The safe apnoea time of the patients in the Naso group was higher than that of the patients in the HFNO group (20 (19.3 to 20.0) vs. 16.5 (12.9 to 20) minutes, P < 0.05). The incidence of SpO 2 < 95% in the Naso group was lower than that in the HFNO group; hazard ratio 0.3 (95% confidence interval 0.2 to 0.6, P < .0001).The modified nasopharyngeal airway which uses far less oxygen than HFNO is a convenient and effective method of apnoeic oxygenation in normal female patients. Trial registration: www.chictr.org.cn,ChiCTR2000039433；date of registration:28/10/2020