van der Mooren K, Barendregt L G, Wladimiroff J W
Department of Obstetrics and Gynaecology, Academic Hospital Rotterdam-Dijkzigt, Erasmus University Rotterdam, The Netherlands.
Pediatr Res. 1991 Nov;30(5):487-90. doi: 10.1203/00006450-199111000-00017.
Maximum flow velocity wave forms in the ductus arteriosus were studied longitudinally in 40 fetuses from 18 to 38 wk of gestation at 3- to 4-wk intervals. Median maternal age was 29 y (range 18-41 y), median parity was 1 (range 0-6). All flow velocity wave forms were obtained using a mechanical sector scanner with a continuous Doppler system (carrier frequency 3.5 MHz). The flow velocity parameters studied were peak-systolic, peak-diastolic, and time-averaged velocity and acceleration time. There was considerable variability in measurements between fetuses at any particular gestational age. An increase of ductal flow parameters with advancing gestational age was found. They showed no correlation with heart rate. These results suggest that the normal second half of pregnancy is characterized by a reduction in right ventricular afterload. This may be a result of decreased placental vascular resistance or increased pulmonary vascular flow. Acceleration time in ductal flow velocity wave forms was significantly higher than that observed in the pulmonary artery and ascending aorta, suggesting a lower afterload in the ductus arteriosus compared with the other two outflow tract vessels.
在妊娠18至38周的40例胎儿中，以3至4周的间隔对动脉导管中的最大流速波形进行了纵向研究。母亲年龄中位数为29岁（范围18 - 41岁），产次中位数为1（范围0 - 6）。所有流速波形均使用带有连续多普勒系统（载波频率3.5 MHz）的机械扇形扫描仪获得。所研究的流速参数包括收缩期峰值、舒张期峰值、时间平均速度和加速时间。在任何特定孕周的胎儿之间，测量值存在相当大的变异性。发现随着孕周增加，动脉导管血流参数增加。它们与心率无相关性。这些结果表明，妊娠后半期的正常特征是右心室后负荷降低。这可能是胎盘血管阻力降低或肺血管血流量增加的结果。动脉导管流速波形中的加速时间明显高于肺动脉和升主动脉中的加速时间，表明与其他两个流出道血管相比，动脉导管的后负荷较低。
