1临床资料患者女,33岁,ASA II。因“l、G4Po孕40周头位活胎;2、骨盆入口狭窄。”拟行子宫下段剖宫产术。患者既往体健,否认外伤、手术史及麻醉史、无药物过敏史。术前查体无异常发现。各种辅助检查结果正常。拟行连续硬膜外麻醉下手术。患者未用术前药。进入手术室后开放静脉输 1 Clinical data Female patient, 33 years old, ASA II. Due to “l, G4Po first 40 weeks of pregnancy live births; 2, pelvic stenosis.” The proposed cesarean section lower uterine segment. Past physical health of patients, denied trauma, history of surgery and anesthesia history, no history of drug allergy. Preoperative examination no abnormal findings. Auxiliary examination results were normal. Proposed continuous epidural anesthesia surgery. Patients did not use preoperative drugs. After entering the operating room open intravenous infusion