Räsänen J, Jouppila P
Department of Obstetrics and Gynecology, University of Oulu, Finland.
J Perinat Med. 1994;22(4):301-8. doi: 10.1515/jpme.1994.22.4.301.
Paracervical block during labor following normal, uncomplicated pregnancy is occasionally accompanied by fetal bradycardia. To evaluate whether a paracervical block with bupivacaine causes changes in the vascular resistance of uteroplacental and umbilicoplacental blood flow, a total of 12 singleton, uncomplicated pregnancies in active labor at the end of pregnancy were included to this study. By using pulsed color Doppler ultrasound techniques the pulsatility indices were measured from both uterine and umbilical arteries before, one minute and 20 minutes after a paracervical block with bupivacaine. Pulsatility indices of both uterine and umbilical arteries remained unchanged throughout the study period, as did fetal and maternal heart rates. In two cases fetal bradycardia developed, causing a marked increase in the vascular resistance of the umbilical artery one minute after the paracervical block. In the uterine arteries there was only a minor increase. When the fetal bradycardia ceased the pulsatility indices returned to the levels at the beginning of the study. Paracervical block with bupivacaine in normal pregnancies without signs of chronic or acute fetal distress does not change the vascular resistance in the uterine or umbilical arteries. If fetal bradycardia develops, it seems to be due to the direct effect of bupivacaine on the fetus, mainly on the umbilical vessels.
正常、无并发症的妊娠在分娩时进行宫颈旁阻滞偶尔会伴有胎儿心动过缓。为评估布比卡因宫颈旁阻滞是否会引起子宫胎盘和脐胎盘血流血管阻力的变化，本研究纳入了12例单胎、无并发症且在妊娠末期处于活跃期分娩的孕妇。通过使用脉冲彩色多普勒超声技术，在布比卡因宫颈旁阻滞前、阻滞1分钟后及20分钟后测量子宫动脉和脐动脉的搏动指数。在整个研究期间，子宫动脉和脐动脉的搏动指数以及胎儿和母亲的心率均保持不变。有2例出现胎儿心动过缓，在宫颈旁阻滞1分钟后脐动脉血管阻力显著增加，子宫动脉仅有轻微增加。当胎儿心动过缓停止时，搏动指数恢复到研究开始时的水平。在无慢性或急性胎儿窘迫迹象的正常妊娠中，布比卡因宫颈旁阻滞不会改变子宫或脐动脉的血管阻力。如果出现胎儿心动过缓，似乎是布比卡因对胎儿，主要是对脐血管的直接作用所致。
