Risk Factors Of Hypotension In Women With Severe Preeclampsia After Spinal Anesthesia During Cesarean Section And The Establishment Of Prediction Model

Objective To analyze the risk factors of hypotension after spinal anesthesia in severe preeclampsia,and to construct a nomogram model,so as to provide an objective quantitative reference tool for anesthesiologists to predict hypotension after anesthesia in such pregnant women.Methods A total of 342 women with severe preeclampsia who underwent cesarean section under spinal anesthesia in the Third Affiliated Hospital of Guangzhou Medical University from November 01,2017 to December 30,2022 were collected.Hypotension was defined as systolic blood pressure less than or equal to90 mm Hg or a decrease of more than 30% of basal systolic blood pressure or the use of vasopressor drugs(e.g.,ephedrine,methamine,phenylephrine)between the time of combined spinal-epidural anesthesia and delivery of the fetus.The patients are divided into hypotension group and non-hypotension group according to whether hypotension occurred.The patient’s medical record information,preoperative diagnosis,medical order,preoperative laboratory examination,obstetric related factors,maternal vital signs during the perioperative period of anesthesia,anesthetic drug use,and some anesthesia related information such as block level were collected.The variables with statistical differences(P < 0.05)in univariate analysis between the two groups were included in multivariate logistic regression analysis to identify the independent risk factors for hypotension.A nomogram model was constructed for various risk factors.To evaluate the power of prediction of the model,the ROC curve was drawn and the area under the curve(AUC)was calculated.At the same time,the prediction model was verified by random repeated sampling,and the calibration curve was drawn.Results A total of 187 cases(55%)of severe preeclampsia had hypotension after combined spinal-epidural anesthesia.Through univariate analysis,there are 14 independent variables that may lead to hypotension after combined lumbar and epidural anesthesia between the two groups,including BMI,WBC,RBC,PLT,fibrinogen,creatinine,albumin/globulin ratio,inter ventricular septum(IVS),left ventricular posterior wall thickness(LVPW),whether nicardipine and magnesium sulfate were used at the same time before surgery,abdominal circumference,ASA grading,heart rate(HR),and whether block level > T8.Multivariate logistic regression analysis shows that block level > T8,increased RBC,PLT,abdominal circumference and heart rate at the time of entering the operating room are independent risk factors for hypotension after combined epidural anesthesia in women with severe preeclampsia.The Hosmer lemeshow consistency test showed that P=0.111(> 0.05).The omnibus test of model coefficients showed that the model is statistically significant(P < 0.05)and the model has a good predictive effect.The area under ROC curve of this model is 0.701,the AUC is > 0.7,the sensitivity is 59.4%,the specificity is 72.9%,and the model efficiency is good.The five independent risk factors for hypotension after anesthesia in women with severe preeclampsia are shown as follows:The AUC of RBC is 0.596,the cut-off value is 3.605×1012/L,the sensitivity is 89.3%and the specificity is 25.8%;The AUC of PLT is 0.6,the cut-off value is 184.5×109/L,the sensitivity is 69%,and the specificity is 49%.The AUC of abdominal circumference is 0.576,the cut-off value is 97.5cm,the sensitivity is 58.3%,the specificity is 55.5%.The AUC of heart rate is 0.619,the cut-off value is 100.5 beats per minute,the sensitivity is 32.1%,the specificity is 89%.Anesthesia block level belongs to classification data.First,regression was performed to calculate the predicted value,and ROC curve was drawn according to the predicted value.The area under the curve anesthesia block level is 0.552,The truncation value of the predicted value is 0.04.The sensitivity of anesthesia block leve is 80.7%,specificity is 29.7%.Conclusions In this study,the incidence of hypotension in women with severe preeclampsia after combined spinal-epidural anesthesia is 55%.Logistic step forward regression analysis showed that anesthesia block level > T8,increased red blood cell count,increased platelet count,larger abdominal circumference,and faster heart rate on entering the operating room are independent risk factors of hypotension after combined anesthesia in severe preeclampsia.Attention should be paid to identify the risk factors of hypotension after spinal anesthesia before surgery,such as red blood cell count,platelet,abdominal circumference and heart rate when entering the operating room.Remember that the anesthesia block level should be prevented from being too high and rising too fast during anesthesia,and measures should be taken to prevent and treat hypotension to ensure the safety of mother and child.This study successfully constructed a Nomogram model to predict the occurrence of hypotension after combined spinal-epidural anesthesia in patients with severe preeclampsia.The model has good predictive efficacy and clinical value,which can help anesthesiologists strengthen the perioperative management of such severe pregnant women,optimize clinical decision-making,and improve maternal and infant outcomes.