Comparison of transnasal humidified rapid-insufflation ventilatory exchange and face mask ventilation on safe apneic duration in elderly minimally-toothed patients：A Randomized Controlled Tria

Abstract

Objective: To compare the effect of THRIVE with face mask ventilation on oxygenation and safe apneic duration after induction of general anesthesia in elderly minimally-toothed patients. Method:Single university-affiliated hospital, conducted from October 2021 to December 2021. Totally 50 patients aged ≥ 65 years with ≥ 10 missing teeth, American Society of Anesthesiology physical status I-III, Mallampati class I-II, who underwent elective surgery under general anesthesia with tracheal intubation, were randomly enrolled and assigned to a facemask group (Group M) and a THRIVE group (Group T) with a random number table. Patients in Group M were pre-oxygenated with a facemask (100% oxygen at a flow rate of 6 L/min). In Group T, patients with their mouths closed were pre-oxygenated via THRIVE (100% oxygen at a flow rate of 30 L/min). After anesthesia induction, patients in Group M were ventilated with pressure-controlled ventilation, and then the facemask was removed to stop the mask ventilation. In Group T, the patient’s mouth was kept closed, and the flow rate was adjusted to 70 L/min. Then, THRIVE was continued with an open mouth. When the safe apneic duration lasted up to 8 minutes or SpO2 decreased to 95%, observation was ended, and the patient was immediately intubated with a video laryngoscope. Tracheal intubation was successfully performed on the first attempt. The safe apneic time (SAT) (from 4 min after muscle relaxant administration to the time until SpO2 dropped to 95%) was measured. Result: Fifty patients were included in the trail. Group T patients had a significantly longer SAT compared to Group M (P=0.000). All 25 patients in Group T reached 8 minutes with their SpO2 maintained at >95%. In Group M, 6 patients (24%) maintained their SpO2 at >95% for 8 minutes. Conclusion: THRIVE, compared with facemask ventilation, can significantly increase the safe apneic duration, improve oxygenation, and shorten the reoxygenation time in elderly minimally-toothed patients during the induction of general anesthesia, which contributes to stable hemodynamics and safe tracheal intubation.