Svanström M C, Biber B, Hanes M, Johansson G, Näslund U, Bålfors E M
Department of Thoracic Anaesthesiology, Umeå University Hospital, SE-901 85 Umeå, Sweden.
Br J Anaesth. 2008 May;100(5):683-9. doi: 10.1093/bja/aen071. Epub 2008 Apr 2.
ECG changes, similar to those seen during myocardial ischaemia, together with symptoms of chest pain, are common during Caesarean section (CS). We hypothesized that oxytocin administration has cardiovascular effects leading to these symptoms and ECG changes.
Forty women undergoing elective CS under spinal anaesthesia were given an i.v. bolus of either 10 IU of oxytocin (Group OXY-CS, n=20) or 0.2 mg of methylergometrine (Group MET-CS, n=20), in a double-blind, randomized fashion after delivery. Ten healthy, non-pregnant, non-anaesthetized women were used as normal controls (Group OXY-NC, n=10) and were given 10 IU of oxytocin i.v. Twelve-lead ECG, on-line, computerized vectorcardiography (VCG), and invasive arterial pressure were recorded.
Oxytocin produced a significant increase in heart rate, +28 (SD 4) and +52 (3) beats min(-1) [mean (SEM); P<0.001], decreases in mean arterial pressure, -33 (2) and -30 (3) mm Hg (P<0.001), and increases in the spatial ST-change vector magnitude (STC-VM), +77 (12) and +114 (8) microV (P<0.001), in CS patients and controls, respectively. Symptoms of chest pain and subjective discomfort were simultaneously present. Methylergometrine produced mild hypertension and no significant ECG changes.
Oxytocin administered as an i.v. bolus of 10 IU induces chest pain, transient profound tachycardia, hypotension, and concomitant signs of myocardial ischaemia according to marked ECG and STC-VM changes. The effects are related to oxytocin administration and not to pregnancy, surgical procedure, delivery, or sympathetic block from spinal anaesthesia.
剖宫产（CS）过程中，类似于心肌缺血时出现的心电图变化以及胸痛症状很常见。我们推测，静脉滴注缩宫素会产生心血管效应，从而导致这些症状和心电图变化。
40名接受脊髓麻醉下择期剖宫产的女性在分娩后以双盲、随机方式静脉推注10 IU缩宫素（缩宫素组，OXY-CS，n = 20）或0.2 mg甲基麦角新碱（麦角新碱组，MET-CS，n = 20）。10名健康、未怀孕、未麻醉的女性作为正常对照（缩宫素正常对照组，OXY-NC，n = 10），静脉注射10 IU缩宫素。记录12导联心电图、在线计算机化向量心电图（VCG）和有创动脉压。
缩宫素使剖宫产患者和对照组的心率显著增加，分别为+28（标准差4）和+52（3）次/分钟[平均值（标准误）；P<0.001]，平均动脉压降低，分别为-33（2）和-30（3）mmHg（P<0.001），空间ST段变化向量幅度（STC-VM）增加，分别为+77（12）和+114（8）μV（P<0.001）。同时出现胸痛症状和主观不适。甲基麦角新碱引起轻度高血压，且无显著心电图变化。
静脉推注10 IU缩宫素会诱发胸痛、短暂性严重心动过速、低血压，并根据明显的心电图和STC-VM变化出现心肌缺血的相关体征。这些效应与缩宫素的给药有关，而非与妊娠、手术过程、分娩或脊髓麻醉引起的交感神经阻滞有关。
