Effect of different pressure control mask ventilation on gastric distension during the induction of general anesthesia

ObjectiveTo evaluate the effects of different pressure control mask ventilation on gastric distension during the induction of general anesthesia.

MethodsForty-five patients scheduled by laparoscopic total hysterectomy were divided into the P10 group, P15 group and P20 group according to different ventilation pressure(15 cases in each group).The P10 group, P15 group and P20 group were given 10, 15 and 20 cmH₂O pressure during mask ventilation, respectively.The SpO₂ and tidal volume were recorded before anesthesia induction(T0), and at 30 s(T1), 60 s(T2), 90 s(T3) and 120 s(T4) of the locking mask ventilation, and the P_ETCO₂ was recorded immediately after laryngeal mask placement(T5).The endoscopic grading of gastric morphology was recorded at the beginning of surgery.At T0 and T5, the anterior-posterior axis diameter and left-right axis diameter of gastric antrum were measured by ultrasound, and the cross-sectional area(CSA) of gastric antrum and the percentage of gastric distension were calculated.

ResultsAll patients completed the study except 1 patient with laryngeal mask leakage in P20 group.At T0, there was no statistical significance in the gastric antrum CSA among three groups(P>0.05).At T5, the difference of CSA in P20 group was higher than that in P10 group and P15 group(P < 0.05), and which in P15 group was higher than that in P10 group(P < 0.05).At T0, the differences of the percentage of flatulence and grading of stomach morphology among three groups were statistically significant(P < 0.05).At T5, the P_ETCO₂ in P20 group was lower than that in P10 group and P15 group(P < 0.05), and which in P15 group was lower than that in P10 group(P < 0.05).At T0, the differences of the SpO₂ among three groups were not statistically significant(P>0.05).From T1 to T4, the SpO₂ in P15 group and P20 group was higher than that in P10 group(P < 0.05).At T2 and T3, the SpO₂ in P20 group was higher than that in P15 group(P < 0.05).From T1 to T4, the tidal volume in P20 group was higher than that in P10 group and P15 group(P < 0.05), and which in P15 group was also higher than that in P10 group(P < 0.05).

ConclusionsDuring the laparoscopic total hysterectomy, the mask ventilation with 10-15 cmH₂O pressure mode can reduce the gastric distention while ensuring adequate lung ventilation.The ultrasonographic measurement of gastric antrum area is feasible to evaluate gastric distension.