超声评价正常中晚孕胎儿上腔静脉形态及血流变化规律的研究

摘要

Objective To evaluate the morphologic and hemodynamic changes of fetal superior vena cava (SVC) with gestational age during the second and third trimester by ultrasound.Methods Two hundred normal singleton pregnancies between 20 and 40 weeks of gestation from our out-patient department were included.They were divided into 5 groups (20-24 weeks,24 +1-28 weeks,28 + 1-32 weeks,32+1-36 weeks,36+t-40 weeks) with 40 cases for each group.SVC diameter and length were measured by two-dimensional ultrasound at approximately 0.5-1.0 cm away from the right atrium-SVC junction along the longitudinal axis of SVC.SVC Doppler flow spectra were obtained and the characteristics of the spectra changes with gestational age were observed.Results Both the SVC diameter and displayable length were closely correlated with gestational age (r =0.908,r =0.585,P ＜0.01 respectively).Doppler interrogation of the SVC revealed the waveform was composed of S-wave,D-wave,and a small,reversed Awave in all fetuses.The velocity of S,D and A waves increased significantly after 28 weeks gestational age (P ＜ 0.05).Conclusions SVC diameter and displayable length have close correlation with gestational age,SVC flow velocities changes regularly with gestational age.%目的 研究正常中晚孕胎儿上腔静脉形态及血流动力学随孕周变化规律,为评价胎儿右心功能及血流动力学变化提供参考依据.方法 门诊产检健康孕20～40周妇女200例,均为单胎.根据孕周分为5组(20～24周,24+1～28周,28+1～32周,32+1～36周,36+1～40周),各组40例.应用二维超声在上腔静脉长轴切面距右房入口0.5～1.0 cm处测量其内径及显示长度,并应用多普勒超声测量血流频谱,观察其在不同孕周的变化规律.结果 正常胎儿上腔静脉内径随孕周增加面增宽(r=0.908,P＜0.01);其显示长度随孕周增加而增加(r=0.585,P＜0.01).正常胎儿上腔静脉呈三相波:心室收缩期波(S波),心室舒张期波(D波)及心房收缩期反向波(A波).S波、D波及A波在妊娠早中期(＜28周)流速较低,在20～24周与24+t～28周组间流速差异无统计学意义;在28周之后流速明显增高(P＜0.05),24+1～28周与28+1～32周及32+1～36周组之间比较流速差异有统计学意义(P＜0.05),而32+1～36周与36+1～40周比较差异无统计学意义.结论 正常中晚孕胎儿上腔静脉内径、显示长度随孕周增加而增加,血流速度随孕周呈规律性变化.