Changes In Cross-sectional Area And Wall Thickness Of Gastric Antrum During Induction Of General Anesthesia And Prediction Of Risk Factors For Postoperative Nausea And Vomiting

Objective To observe the changes of cross-sectional area and wall thickness of gastric antrum at different administration points during induction of general anesthesia by tracheal intubation under bedside ultrasound monitoring,and to explore the possible relationship between induced drμgs and reflux aspiration.Methods This study is a single center cross-sectional study of 150 patients undergoing elective surgery at the Affiliated Hospital of Jiaxing University from Aμ gust 2021 to November 2022 under ASA Ⅰ-Ⅱ general anesthesia throμgh tracheal intubation.After entering the operating room,before anesthesia induction(T0),the induced doses of propofol(2mg/kg)and rocuronium(0.6mg/kg)were injected intravenously for 90s(T1).After the injection of sufentanil(0.5 μg/kg)took effect,the patient was intubated,and after intubation(T2),the patient was kept in a 45 degree semi recumbent position at three time points.The cross-sectional area(CSA)and wall thickness(WT)of the gastric antrum were measured and recorded using bedside ultrasound,respectively.GV was calculated based on the formula for calculating gastric volume(GV)in the patient’s 45 degree semi recumbent position,and the unit weight GV(GV/weight,GV/W)was further calculated to assess the risk of reflux aspiration.Results 150 patients were included in this study,including 14 patients who had difficulty measuring due to unclear imaging of the gastric antrum or artifacts in gastric intake,10 patients who violated the protocol(using fentanyl for induction during anesthesia induction),and 2 patients who refused to be enrolled before induction.Finally,124 patients were actually included for statistical analysis.The results showed that during the induction of general anesthesia,the CSA,GV,and GV/W gradually decreased at the three time points T0,T1,and T2,with a statistically significant difference(P<0.05),while there was no statistically significant difference in WT changes(P>0.05).Conclusions Under the conditions of this clinical observation,the induction dose of propofol and rocuronium during the induction period of general anesthesia will reduce the CSA.After the combined induction dose of sufentanil,the CSA will further decrease,with no significant changes in WT,accelerated gastric emptying,and reduced risk of reflux and aspiration during the induction period of general anesthesia.Objective To explore the relationship between the changes in cross-sectional area and thickness of gastric antrum under ultrasound monitoring at different administration points during the induction period of general anesthesia and postoperative nausea and vomiting,and to provide new ideas for preventing postoperative nausea and vomiting.Methods The incidence of nausea and vomiting in 142 patients undergoing tracheal intubation and general anesthesia within 24 hours after surgery was evaluated based on the WHO nausea and vomiting rating.When the patient has a nausea and vomiting rating of 1 within 24 hours after surgery,it is determined that the patient has PONV.Based on this result,the patients were divided into PONV group and non PONV group,to explore the changes in CSA and WT in the two groups,and to screen for relevant risk factors for the occurrence of PONV.Results The data of 124 patients were actually included in this study for statistical analysis.The results showed that there was no statistically significant difference in the changes in CSA and WT at the three time points T0,Tl,and T2 in the group with PONV(28 cases/22.6%),while the CSA gradually decreased at the three time points T0,Tl,and T2 in the non PONV group(96 cases/77.4%),with a statistically significant difference(P<0.05),and there was no statistically significant difference in WT changes(P>0.05).However,there was no statistically significant difference in the changes in CSA and WT between the PONV group and the non PONV group at each time point(P>0.05).A binary logistic regression analysis of PONV revealed that gender,a history of PONV or/and motion sickness were independent risk factors for the occurrence of PONV,while changes in CSA and WT at the three time points were not risk factors for PONV.In this study,the area under the working characteristic curve(AUC)of subjects in the binary logistic model was 0.874,which had a statistically significant prediction of PONV in patients(P<0.05).Conclusions This clinical observational study found that women,a history of PONV or/and motion sickness are independent risk factors for the occurrence of PONV.