Brar H S, Medearis A L, DeVore G R, Platt L D
Department of Obstetrics and Gynecology, University of Southern California School of Medicine, Los Angeles.
Obstet Gynecol. 1988 Aug;72(2):209-14.
The effect of tocolytics on systolic to diastolic (S/D) ratios used to assess downstream vascular resistance and obtained from umbilical and uterine velocity waveforms has not been studied to date. Continuous-wave Doppler studies were performed on the umbilical and uterine arteries of 60 consecutive patients with the diagnosis of preterm labor. Forty patients receiving intravenous magnesium sulfate and 20 patients receiving intravenous ritodrine tocolysis underwent Doppler studies before therapy, during incremental therapy, and four hours post-therapy. There was a statistically significant (P less than .001) progressive decrease in the uterine and umbilical S/D ratios along with a concomitant increase in maternal and fetal heart rate associated with increasing infusion doses of ritodrine. Both the S/D ratios and heart rates returned to pretherapy range four hours after discontinuing therapy. Magnesium sulfate tocolysis was not associated with any significant change in S/D ratios or maternal and fetal heart rate. We conclude that intravenous ritodrine affects umbilical and uterine vascular resistance as measured by S/D ratios. This response may be secondary to changes in maternal and fetal heart rate.
目前尚未研究宫缩抑制剂对用于评估下游血管阻力且从脐动脉和子宫速度波形获得的收缩压与舒张压（S/D）比值的影响。对60例连续诊断为早产的患者的脐动脉和子宫动脉进行了连续波多普勒研究。40例接受静脉注射硫酸镁的患者和20例接受静脉注射利托君进行宫缩抑制治疗的患者在治疗前、递增治疗期间及治疗后4小时接受了多普勒研究。随着利托君输注剂量增加，子宫和脐动脉S/D比值出现具有统计学意义的（P小于0.001）逐渐下降，同时母体和胎儿心率随之增加。停止治疗4小时后，S/D比值和心率均恢复至治疗前范围。硫酸镁宫缩抑制治疗与S/D比值或母体和胎儿心率的任何显著变化均无关。我们得出结论，静脉注射利托君会影响通过S/D比值测量的脐动脉和子宫血管阻力。这种反应可能继发于母体和胎儿心率的变化。
