Abstract:

Objective　To explore the influencing factors of hypotension after anesthesia in women taking cesarean section, and to construct a nomagram model. Methods　The clinical data of 269 women who underwent cesarean section at Xianyang First People's Hospital from April 2022 to June 2024 were retrospectively analyzed. According to whether they had hypotension after anesthesia, they were divided into a hypotension group (119 cases) and a non-hypotension group (150 cases). The hypotension group were (31.56±4.28) years old; their gestational weeks was (39.05±1.23) weeks; there were 80 cases of grade Ⅰ and 39 cases of grade Ⅱ of American Society of Anesthesiologists (ASA). The non-hypotension group were (30.69±4.03) years old; their gestational weeks was (38.84±0.96) weeks; there were 115 cases of grade Ⅰ and 35 cases of grade Ⅱ of ASA. The clinical data were compared between the two groups. The influencing factors of hypotension in the women after anesthesia were screened using the multiple Logistic regression analysis. A risk prediction nomagram model for hypotension after anesthesia was constructed by the R software and rms package. The clinical application value of the model was validated using the calibration curves, receiver operating characteristic curves (ROC), and decision analysis curves. t and χ² tests were used for the statistical analysis. Results　The proportions of the women with maternal abdominal circumference >100 cm, uterine height >36 cm, and anesthesia level >T4 and the intraoperative bleeding volume in the hypotension group were higher than those in the non-hypotension group [89.08% (106/119) vs. 80.00% (120/150), 11.76% (14/119) vs. 4.00% (6/150), 20.17% (24/119) vs. 8.67% (13/150), and (326.52±65.39) ml vs. (301.43±62.68) ml], with statistical differences (χ²=4.070, 5.813, and 7.399; t=3.199; all P<0.05). The prenatal hemoglobin level and the proportions of the women with left lateral tilt of position and prophylactic medication in the hypotension group were lower than those in the non-hypotension group [(125.95±13.46) g/L vs. (132.53±12.68) g/L, 71.43% (85/119) vs. 88.67% (133/150), and 56.30% (67/119) vs. 76.67% (115/150)], with statistical differences (t=4.113; χ²=12.833 and 12.576; all P<0.05). The multivariate logistic regression analysis showed that uterine height > 36 cm, low prenatal hemoglobin level, big intraoperative bleeding volume, and anesthesia level > T4 were the risk factors for hypotension after cesarean section (OR=1.808, 1.906, 1.866, and 2.268; all P<0.05), while left lateral tilt of position and prophylactic medication were the protective factors for it (OR=0.510 and 0.490; both P<0.05). The internal validation showed that the model's consistency index was 0.868; the calibration curve showed that the calibration curve was close to the ideal curve; the ROC showed that its sensitivity, specificity, and area under the curve were 86.67%, 80.71%, and 0.867%, respectively; the decision curve analysis showed that when the threshold probability was between 0.52 and 0.80, the model could obtain a good net profit value. Conclusions　Uterine height >36 cm, low prenatal hemoglobin level, big intraoperative bleeding volume, anesthesia level >T4, left lateral tilt of position, and prophylactic medication are all the factors affecting the occurrence of hypotension in women taking cesarean section after anesthesia. The nomagram model constructed based on this has high clinical application value, and can help clinicians screen high-risk cesarean section women who experience hypotension after anesthesia in the early stage and guide clinical work.

Key words:

Cesarean section, Anesthesia, Hypotension, Influencing factors, Nomagram

摘要：

目的　探讨剖宫产产妇麻醉后发生低血压的影响因素，并构建列线图模型。方法　采用回顾性研究，选取2022年4月至2024年6月在咸阳市第一人民医院行剖宫产手术的269例产妇临床资料，按麻醉后低血压发生情况，将出现低血压的119例产妇归为低血压组，未出现低血压的150例产妇归为非低血压组。低血压组：年龄（31.56±4.28）岁，孕周（39.05±1.23）周；美国麻醉医师协会（ASA）分级：Ⅰ级80例，Ⅱ级39例。非低血压组：年龄（30.69±4.03）岁，孕周（38.84±0.96）周；ASA分级：Ⅰ级115例，Ⅱ级35例。比较两组临床资料，采用多因素logistic回归分析筛查剖宫产产妇麻醉后发生低血压的影响因素，使用R软件和rms程序包构建麻醉后低血压的风险预测列线图模型，利用校准曲线、受试者操作特征曲线（ROC）和决策分析曲线对该模型的临床应用价值进行验证。统计学方法采用t检验、χ²检验。结果　低血压组产妇腹围>100 cm、宫高>36 cm、麻醉平面>T4占比及术中出血量均高于非低血压组［89.08%（106/119）比80.00%（120/150）、11.76%（14/119）比4.00%（6/150）、20.17%（24/119）比8.67%（13/150）、（326.52±65.39）ml比（301.43±62.68）ml，差异均有统计学意义（χ²=4.070、5.813、7.399，t=3.199，均P<0.05）；低血压组产前血红蛋白水平和体位左侧倾斜、预防性用药占比均低于非低血压组［（125.95±13.46）g/L比（132.53±12.68）g/L、71.43%（85/119）比88.67%（133/150）、56.30%（67/119）比76.67%（115/150）］，差异均有统计学意义（t=4.113，χ²=12.833、12.576，均P<0.05）。多因素logistic回归分析显示宫高>36 cm、产前血红蛋白低、术中出血量大、麻醉平面>T4均是剖宫产产妇麻醉后发生低血压的危险因素［比值比（OR）=1.808、1.906、1.866、2.268，均P<0.05］，体位左侧倾斜、预防性用药是其保护因素（OR=0.510、0.490，均P<0.05）。列线图模型经内部验证显示一致性指数为0.868，校准曲线显示校正曲线与理想曲线相贴近，ROC显示其灵敏度、特异度、曲线下面积分别为86.67%、80.71%、0.867，决策曲线分析显示当阈概率在0.52～0.80时，该模型可得到良好的净收益值。结论　宫高>36 cm、产前血红蛋白低、术中出血量大、麻醉平面>T4、体位左侧倾斜、预防性用药均是剖宫产产妇麻醉后发生低血压的影响因素，基于此构建的列线图模型临床应用价值高，有助于临床医师早期筛查出麻醉后发生低血压的高风险剖宫产产妇，以指导临床工作。

关键词:

剖宫产, 麻醉, 低血压, 影响因素, 列线图