The Effect Of Epidural Analgesia Duration On The Choice Of Anesthesia Method As Cesarean Section

Research background and purpose:Currently,epidural labor analgesia is thought of as the most effective and popular method for labor analgesia,which can not only alleviate the labor pain,but also convert to epidural anesthesia by adding local anesthetics via epidural catheter,providing anesthesia when cesarean section is needed due to failed vaginal delivery.However,converting from epidural labor analgesia to epidural anesthesia has a possibility of insufficient block or even ineffective block that brings additional risk to pregnant women and/or newborns,because the unrecognized failure of conversion before operation will lead to unplanned anesthesia method change.The number of pregnant women who might undergo such conversion is surging alongside the incessantly popularizing of epidural labor analgesia,implying the effectiveness of conversion should be accurately considered by anesthesiologist in order to choose proper anesthesia method timely and rapidly before cesarean section.Researches have showed that younger,obese,explosive pain,insufficient analgesia,high urgency of cesarean section and so on,as well as epidural labor analgesia implemented by non-obstetric specialist anesthesiologist,are related to insufficient block or even ineffective block.Pregnant women who have the risk factors mentioned above are more likely and more necessary to use other anesthesia methods before cesarean section,but whether the analgesia duration will affect the choice of anesthesia method remains unclear.Materials and Methods:The materials of pregnant women who received epidural labor analgesia and underwent cesarean section between June 2020 and June 2021 at the Sichuan Provincial Maternity and Child Health Care Hospital,Chengdu Women’s and Children’s Central Hospital,and Chengdu Jinjiang Hospital for Women and Children Health were included.Based on the anesthesia method as cesarean section,they were divided into three groups: epidural anesthesia,spinal anesthesia,and general anesthesia groups.The independent risk factors affecting the choice of anesthesia methods are explored by multivariate logistic regression analysis.If analgesia duration is independent risk factor,using it to construct the receiver operating characteristic curve,and Youden index is used to determine the critical value of it.Then divide pregnant women into two groups according to the critical value and use cross table to calculate the relative risk of each group to define is there a significant increase in the risk of changing anesthesia method for group with longer analgesia duration than critical value.This study was approved by the ethics committee of Sichuan maternal and Child Health Hospital-20210109-01,Jinjiang Maternal and Child Health Hospital-202111,and Chengdu Women’s and Children’s Central Hospital-B2019(12).Results:1.Sichuan Provincial Maternity and Child Health Care Hospital: a total of 334 pregnant women were included,227 cases(67.96%)in the epidural anesthesia group,100(29.94%)in spinal anesthesia group,7(2.10%)in the general anesthesia group all the immediate cesarean section.The analgesia duration in epidural anesthesia group was significantly shorter than spinal anesthesia group(9.58h±5.05 h vs 11.22h±5.48 h,P<0.01).The analgesia duration in general anesthesia group was 8.29h±6.42 h.2.Chengdu Women’s and Children’s Central Hospital: a total of 566 pregnant women were included,4 cases had failed epidural anesthesia and were administered general anesthesia before operation,so 430(75.97%)in the epidural anesthesia group,124(21.91%)in spinal anesthesia group,12(2.12%)in the general anesthesia group including 4 epidural anesthesia failed and 8 immediate cesarean section.The analgesia duration in epidural anesthesia group was significantly shorter than spinal anesthesia group(7.48h±4.29 h vs 9.39h±4.64 h,P<0.01).The analgesia duration in general anesthesia group was 5.75h±4.31 h.3.Chengdu Jinjiang Hospital for Women and Children Health: a total of 184 pregnant women were included,47(25.55%)in the epidural anesthesia group,133(72.28%)in spinal anesthesia group,4(2.17%)in the general anesthesia group all the immediate cesarean section.The analgesia duration in epidural anesthesia group was significantly shorter than spinal anesthesia group(6.34h±3.27 h vs 8.43h±4.64 h,P<0.01).The analgesia duration in general anesthesia group was 12.50h±5.75 h.4.Three hospitals in Chengdu: a total of 1084 pregnant women were included,4cases had failed epidural anesthesia and were administered general anesthesia before operation,so 704(64.94%)in the epidural anesthesia group,357(32.93%)in spinal anesthesia group,23(2.13%)in the general anesthesia group including 4 epidural anesthesia failed and 19 immediate cesarean section.The analgesia duration in epidural anesthesia group was significantly shorter than spinal anesthesia group(8.08h±4.61 h vs9.54h±4.94 h,P<0.01).The analgesia duration in general anesthesia group was7.70h±5.60 h.Multivariate logistic regression analysis showed that prolonged analgesia duration(OR=1.09,95% CI 1.05～1.12,P<0.01)was the independent risk factor of anesthesia method change.The critical value of analgesia duration was 8 hours,and the relative risk of pregnant women receiving spinal anesthesia who have duration over 8hours was 1.27(95% CI 1.01～1.47,P<0.01).In addition to analgesia duration,preoperative uterine orifice enlargement(OR=1.06,95% CI 1.01-1.10,P<0.01)was also independent risk factor.Artificial rupture of membranes(OR=0.44,95% CI 0.33～0.60,P<0.01)and diabetes(OR=0.56,95% CI 0.38～0.82,P<0.01)were associated with the successful conversion of epidural anesthesia.