Comparison of development of gastric insufflation related to different peak inspiratory pressures during facemask ventilation in pediatric patients: ultrasonographic measurement / 中华麻醉学杂志

ABSTRACT

Objective To compare the development of gastric insufflation related to different peak inspiratory pressures (PIPs) during facemask ventilation in the pediatric patients.Methods Ninety male pediatric patients,aged 2-4 yr,of American Society of Anesthesiologists physical status Ⅰ,scheduled for elective surgery under general anesthesia,were randomly divided into 5 groups (n =18 each) using a random number tablePIP 8 cmH2O group (group P8),PIP 10 cmH2O group (group P10),PIP 12 cm H2O group (groupP12),PIP 14cmH2O group (group P14) and PIP 16 cmH2O group (group P16).Anesthesia was induced with fentanil,propofol and rocuronium in sequence.After loss of eyelash reflex,positive pressure facemask ventilation was performed for a 120 s period in pressure-controlled mode.Gastric insufflation was detected by real-time ultrasonography of the antrum,and cross-sectional antral area was measured using ultrasonography before facemask ventilation and at 120 s of facemask ventilation.The pulse oximetry (SpO2),tidal volume (VT),end-tidal pressure of carbon dioxide (PETCO2) and end-tidal oxygen concentration (ETO2) were recorded at 30,60,90,and 120 s of facemask ventilation.The development of gastric insufflation and hypoventilation was recorded.Results Compared with group P8,the incidence of gastric insufflation was significantly increased in group P16 (P＜0.01),and no significant change was found in the incidence of gastric insufflation in the other groups (P＞0.05),the incidence of hypoventilation was significantly decreased,VT and ETO2 were increased,and PET CO2 was decreased in P12,P14 and P16 groups,and PETCO2 was significantly decreased at 120 s of facemask ventilation (P＜ 0.05 or 0.01),and no significant change was found in the other parameters in group P10 (P＞0.05).Compared with P12 and P14 groups,VT was significantly increased,PEHTCO2 was decreased at 120 s of facemask ventilation (P＜0.05),and no significant change was found in the incidence of hypoventilation and ETO2 in group P16 (P＞0.05).There was no significant difference between group P12 and group P14 in the incidence of hypoventilation,VT,PETCO2 and ETO2 (P＞0.05).The pediatric patients showed a certain CO2 accumulation [PETCO2 (40.6±4.0) mmHg] at 120 s of facemask ventilation in group P8,and the pediatric patients showed excessive ventilation [PETCO2 (23.6± 1.4) mmHg],and cross-sectional antral area was not measured using ultrasonography in three cases because of excessive gastric insufflation in group P16.Conclusion PIP at 12-14 mmHg in pressure-controlled ventilation mode can not only ensure adequate preoxygenation and but also avoid excessive gastric insufflation during facemask ventilation in the pediatric patients.