Laudy J A, de Ridder M A, Wladimiroff J W
Department of Obstetrics and Gynaecology, University Hospital Rotterdam-Dijkzigt, The Netherlands.
Pediatr Res. 1997 Jun;41(6):897-901. doi: 10.1203/00006450-199706000-00016.
The objective of the present study was to determine the characteristics of Doppler flow velocity wave forms in branch pulmonary arteries in relation to gestational age. A total of 111 singleton normal pregnancies were studied during the second half of pregnancy using a combined color-coded Doppler and two-dimensional real-time ultrasound system. Pulsed Doppler measurements of the most proximal branch of the right or left pulmonary artery were attempted during fetal apnea from a transverse cross-section of the fetal chest at the level of the cardiac four-chamber view after visualization with color Doppler. The success rate in obtaining the pulmonary arterial wave form was 85%. The wave form displayed a rapid systolic velocity acceleration, followed by an initially rapid but then more gradual velocity deceleration which was interrupted in most cases by a short reversed flow interval at the beginning of the diastolic phase of the cardiac cycle. The diastolic phase was characterized by forward flow. Peak systolic, end-diastolic and time-averaged velocity, pulsatility index, and systolic integral remained constant during gestation. Changes in vessel diameter or compliance may play a role in this. A gestational age-dependent rise was established for peak diastolic velocity, diastolic integral, and early peak diastolic reverse flow, whereas a gestational age-determined decline was found for the peak systolic/peak diastolic ratio. Fetal heart rate demonstrated a statistically significant increase relative to gestational age. However, the observed relation between the flow velocity wave form parameters, pulsatility index calculations, and gestational age was independent of fetal heart rate. It is speculated that peak diastolic velocity, diastolic integral, and peak systolic/peak diastolic ratio rather than the pulsatility index are useful in detecting gestational age-related changes in human fetal pulmonary vascular resistance.
本研究的目的是确定与胎龄相关的分支肺动脉中多普勒血流速度波形的特征。在妊娠后半期，使用彩色编码多普勒和二维实时超声系统对111例单胎正常妊娠进行了研究。在通过彩色多普勒可视化后，从胎儿胸部心脏四腔视图水平的横切面在胎儿呼吸暂停期间尝试对右或左肺动脉最近端分支进行脉冲多普勒测量。获得肺动脉波形的成功率为85%。该波形显示出快速的收缩期速度加速，随后是最初快速但随后更逐渐的速度减速，在大多数情况下，在心动周期舒张期开始时被短暂的反向血流间隔中断。舒张期的特征是正向血流。收缩期峰值、舒张期末和时间平均速度、搏动指数和收缩期积分在妊娠期间保持恒定。血管直径或顺应性的变化可能在其中起作用。舒张期峰值速度、舒张期积分和舒张早期峰值反向血流随胎龄增加，而收缩期峰值/舒张期峰值比值随胎龄下降。胎儿心率相对于胎龄有统计学上的显著增加。然而，观察到的流速波形参数、搏动指数计算与胎龄之间的关系与胎儿心率无关。据推测，舒张期峰值速度、舒张期积分和收缩期峰值/舒张期峰值比值而非搏动指数有助于检测与胎龄相关的人类胎儿肺血管阻力变化。
