Comparison of the changes of antrum and fundus cross-sectional area measured by bedside ultrasonography on gastric insufflation during general anesthesia in non-obese women

Abstract

Objective To compare the changes of antrum and fundus cross-sectional area(CSA) measured by bedside ultrasonography on gastric insufflation during anesthesia induction in non-obese female patients and analyze the relationships between these changes as well as postoperative nausea and vomiting (PONV). Methods Fourty-six patients scheduled for elective gynecological laparoscopic operations were enrolled in the study. The patients who appeared the comet-tail artifacts were defined as gastric insufflation positive group(GI+ group), while the ones without comet-tail artifacts were defined as gastric insufflation negative group(GI- group). Blood oxygen saturation(SPO2), end-expiratory partial pressure of CO2(PETCO2), tidal volume(TV) were recorded after 180 seconds ventilation in both groups. The longitudinal and anteroposterior diameters of gastric antrum and fundus were measured before and after facemask ventilation respectively and the corresponding CSA were calculated. The cutoff values of prediction of gastric insufflation were determined according to the ROC curve and the corresponding sensitivity and specificity were calculated. PONV of the two groups were also recorded. Results The analysis was based on the remaining 41 data sets actually. There were 13 patients in GI- group and 28 ones in GI+ group. Compared with GI- group, the changes of TV and fundus CSA in GI+ group had significantly differences(P<0.05); while compared with before mask ventilation, the changes of antrum and fundus CSA in both groups had significantly differences (P<0.05). The areas of antrum and fundus CSA under the ROC curve (95%CI) were 0.67 and 0.80, with cut-off value 3.19 cm2 and 24.90 cm2, sensitivity 0.93 and 0.93 and specificity 0.39 and 0.69, respectively. The incidence of PONV in GI+ group was higher than that in GI- group(P<0.05). Conclusions Changes of fundus CSA by ultrasonography might be superior to antrum CSA in gastric insufflation caused by 20 cmH2O peak airway pressure of facemask ventilation during anesthesia induction. Gastric insufflation caused by positive pressure ventilation is related with PONV for young female patients undergoing gynecological laparoscopic operation. Key words: Ultrasonography; General anesthesia; Gastric insufflation; Antral area; Fundus area; Female