Comparison of different flow rates of transnasal humidified rapid-insufflation ventilatory exchange for prevention of hypoxemia in painless gastroscopy / 中华消化内镜杂志

ABSTRACT

Objective:To explore the clinical effect of different flow rates of transnasal humidified rapid-insufflation ventilatory exchange (Thrive) on hypoxic events during painless gastroscopy.Methods:Patients who underwent painless gastroscopy in Nanjing First Hospital from April to July 2020 were randomly selected by random number table method and assigned to Thrive groups of 30 L/min ( n=52), 50 L/min ( n=55) and 70 L/min ( n=54). The incidences of different degree of hypoxic events (including subclinical respiratory depression, hypoxia and severe hypoxia) and adverse events related to Thrive were recorded. Results:The total incidence of hypoxic events in the 70 L/min group was 0 (0/54), which was significantly lower than that in the 30 L/min group (21.3%, 11/52, χ2=12.75, P<0.001) and 50 L/min group (12.7%, 7/55, P=0.007). There were no significant differences in subclinical respiratory depression [13.5% (7/52) VS 5.5% (3/55), χ2=1.19, P=0.194] or hypoxia [7.7% (4/52) VS 7.3% (4/55), P=0.610] between 30 L/min group and 50 L/min group. No severe hypoxia occurred in any group. The oxygenation of patients with hypoxemia in 30 L/min and 50 L/min groups was improved (SpO 2>95%) after opening the airway by mandibular support. In addition, there were no significant differences in the incidence of adverse events except hypoxemia among the three groups ( P>0.05). Conclusion:The flow rates of Thrive of 30 L/min, 50 L/min, and 70 L/min can prevent the occurrence of severe hypoxia during painless gastroscopy, and the flow rate of 70 L/min can further reduce the incidence of subclinical respiratory depression.