| Placenta accrete spectrum(PAS)is a collective term for a group of disorders in which the placenta abnormally adheres to the myometrium.Failure of the placenta to detach properly from the uterine wall results in an increased risk of maternal perinatal complications including massive blood loss,disseminated intravascular coagulation,organ damage,and even maternal death.Cesarean delivery is usually performed under neuraxial anesthesia,but given the hemodynamic instability due to excessive bleeding and intraoperative hypotension due to sympathetic nerve blockage by neuraxial anesthesia,general anesthesia is usually chosen for cesarean deliveries in patients with PAS.However,general anesthesia has adverse effects on the both mother and child,such as failed intubation,neonatal respiratory depression,and low Apgar scores.There no guidelines on the choice of anaesthesia for caesarean delivery in patients with PAS,and there is controversy between the findings of the various studies.Therefore,this study collected clinical data on patients with PAS from several medical centres in China.Firstly,in the first part,we analysed the effects of different anesthetic modalities during caesarean delivery on maternal and infant outcomes in patients with PAS,and also explored the risk factors associated with poor maternal outcomes.On the basis of chapter 1,in chapter 2,to further develop a predictive model for adverse events in patients with PAS under neuraxial anaesthesia and to risk-stratify patients with PAS undergoing caesarean deliveries under neuraxial anaesthesia.The aim of this study is to provide a guide for the use of anaesthesia during caesarean delivery in patients with PAS in the hope of reducing the incidence of adverse perinatal events and improving maternal and infant pregnancy outcomes.Chapter 1 Comparison of perinatal outcomes between neuraxial and general anesthesia in pregnant women with placenta accreta spectrum:a multicenter retrospective studyObjectivesTo analyze the effects of neuraxial versus general anesthesia on maternal and infant outcomes in patients with placenta accreta spectrum(PAS),and to explore the influencing factors associated with adverse pregnancy outcomes.MethodsThe study is a multicentre retrospective analysis that collected clinical data from 425 patients with PAS at three medical centres from January 2016 to January 2022.Patients were divided into neuraxial group and general anesthesia group according to the actual type of anesthesia received during cesarean delivery.Between-group differences in patients’preoperative characteristics were analyzed by chi-square test,and the propensity score matching(PSM)algorithm was used to balance the differences in patients’ clinical characteristics between the two groups.Influence of anesthesia on maternal and infant outcomes was assessed by the chi-square test,and the factors associated with adverse pregnancy outcomes were investigated by univariate and multivariate logistic regression analysis.ResultsA total of 425 patients were included in the study,including 307(72.2%)in the general anesthesia group and 118(27.8%)in the neuraxial anesthesia group.Significant statistical difference between the two groups was found by chi-square test in terms of number of pregnancies(P=0.047),type of placenta implantation(P=0.005),number of cesarean deliveries(P=0.003),preoperative hemoglobin level(P=0.001),combined hypertension in pregnancy(P=0.003),type of placenta praevia(P<0.001),abdominal aortic balloon placement(P<0.001),and prenatal ultrasound findings(P<0.001).After balancing the differences between groups by PSM analysis,in the matched cohort,the neuraxial anesthesia group had a shorter total operative time(78 min vs.87 min,P=0.030),a shorter postoperative hospital stays(4 days vs.5 days,P=0.037),less intraoperative blood loss(800 ml vs.1500 ml,P<0.001),and fewer transfused red blood cells(2 U vs.4U,P<0.001).Intraoperative uterine artery superior branch ligation rate(39.5 vs.13.6%,P<0.001)and lower uterine segment bundling rate(37.0 vs.18.5%,P=0.009)were higher in the neuraxial anesthesia group.Univariate and multivariate logistic analysis showed that general anesthesia(P<0.001)and vascular lacunae of the placenta(P=0.005)were high risk factors for adverse maternal eventsConclusions1.In the matched group,the total operative time,postoperative hospital stays,intraoperative blood loss and transfusion of red blood cells were less in the neuraxial anesthesia group compared with the general anesthesia group.No difference in neonatal outcome.2.General anesthesia and vascular lacunae of the placenta were high risk factors for adverse maternal events in patients with PAS.3.Conditions for the application of NA to the management of anaesthesia during cesarean delivery need to be further explored.Chapter 2 Construction and validation of a predictive model for adverse pregnancy outcomes in patients with placenta accreta spectrum under neuraxial anesthesiaObjectiveWe aimed to investigate the high-risk factors associated with adverse pregnancy outcomes in patients with PAS under neuraxial anaesthesia,to assess the safety of NA for the intraoperative management of anaesthesia in patients with PAS,to develop a predictive model for adverse pregnancy outcomes in patients with PAS under neuraxial anaesthesia,and to risk-stratify patients with PAS undergoing caesarean delivery under neuraxial anaesthesia.MethodsThis study collected clinical data from 214 patients with PAS who underwent caesarean delivery under neuraxial anaesthesia at three medical centres from January 2016 to January 2022.The chi-square test compared clinical characteristics of patients in the groups with and without adverse pregnancy outcomes.Multivariate logistic regression analysis was uesd to identify risk factors associated with adverse events.Machine learning algorithms were used to develop and validate a predictive model for adverse pregnancy outcomes in PAS patients undergoing caesarean delivery under NA management,and we risk-stratify PAS patients according to their risk score.ResultsA total of 214 patients were included in the study and a total of 67(31.3%)patients had adverse events.A chi-square test and multivariate logistic regression analysis identified age at delivery>33 years(P=0.004),number of caesarean sections>1(P=0.020),preoperative HGB level ≤100g/L(P=0.013),placenta praevia classification(P<0.001),intra-placental vascular invagination(P=0.015),and gestational week(P=0.026)as high risk factors for adverse events.We built and validated a model for predicting the occurrence of adverse events using machine learning algorithms with an area under the receiver receiver operating characteristic curve(AUC)of 0.75-0.79 and an overall accuracy of 0.68-0.71.Based on the constructed model,three risk stratifications were successfully completed for patients:high,medium and low.Conclusion1.Age at delivery>33 years,number of caesarean deliveries>1,preoperative HGB level≤100g/L,classification of placenta praevia,intra-placental vascular invagination,and gestational week were high risk factors for adverse events.2.We have successfully developed a prenatal prediction model with reliable accuracy for assessing the risk of adverse events in patients with PAS under neuraxial anaesthesia.ConclusionThis study analyzed the effects of different anesthesia modalities on maternal and infant outcomes during cesarean delivery based on clinical data of PAS patients from multiple centres in China,and found that NA can be used for anesthetic management during their cesarean delivery in some PAS patients,but the conditions of application need to be further explored.Therefore,we explored the risk factors for adverse events during cesarean delivery in PAS patients under NA in the second part of the study and found that age at delivery>33 years,number of cesarean delivery>1,preoperative HGB level ≤100g/L,placenta praevia classification,intra-placental vascular lacunae,and gestational weeks were independent risk factors for adverse events.We have successfully developed a predictive model and risk stratified PAS patients undergoing cesarean delivery under NA.This model can be used to inform the choice of anaesthesia before caesarean section in patients with PAS.Patients with PAS who are risk stratified as low or moderate risk have a relatively low risk of massive intra-caesarean bleeding and blood transfusion and can choose to have their caesarean section under NA;while for patients in the high risk group,they are advised to choose GA as the surgical anaesthesia for better intraoperative haemodynamic management and to reduce the occurrence of perinatal complications and improve pregnancy outcomes. |
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