A Comparative Study of Two Inspiratory Pressure Levels for Pressure-Controlled Face-Mask Ventilation in Children.

Introduction Inappropriate inspiratory pressure during face mask ventilation at the time of anesthesia induction can cause gastric insufflation. We attempted to determine which inspiratory pressure level is more effective between 12 and 16 cm HO during pressure-controlled face mask ventilation. The primary objective was the measurement and comparison of the cross-sectional area (CSA) of the gastric antrum by ultrasonography before and after face mask ventilation. Materials and methods This comparative randomized trial enrolled 40 children younger than five years who were scheduled for surgery under general anesthesia. Participants received face mask ventilation for four minutes using pressure-controlled ventilation at the time of anesthesia induction with an inspiratory pressure of 12 cm HO (Group P12) or 16 cm HO (Group P16). The cross-sectional area (CSA) of the gastric antrum was measured both before and after face mask ventilation. Respiratory and hemodynamic parameters were also recorded during face mask ventilation. Results Each group shows an increase in the CSA of the gastric antrum after face mask ventilation from baseline values. Antrum CSA increased from 1.13 cm² to 1.24 cm² (p=0.214) in group P12 and from 1.09 cm² to 1.53 cm² (p=0.001) in group P16. The intergroup difference after face-mask ventilation antral CSA was also significant among groups (p=0.035). The P12 group was able to generate adequate tidal volume while it was more than needed (9-10 ml/kg) in group P16. No event of regurgitation, bronchospasm, or laryngospasm was recorded in any group. Conclusion The antral cross-sectional area after face mask ventilation was greater with 16 cm H₂O inspiratory pressure than with 12 cm H₂O. Furthermore, the use of 16 cm H₂O inspiratory pressure resulted in a tidal volume greater than necessary.