Anderson D F, Faber J J, Morton M J, Parks C M, Pinson C W, Thornburg K L
J Physiol. 1985 Aug;365:29-40. doi: 10.1113/jphysiol.1985.sp015757.
Right and left atrial pressures were measured in eight chronically instrumented fetal and neonatal lambs. Flows were measured with a combination of electromagnetic flow sensor and microsphere techniques. Three of the fetuses were ventilated in utero during the measurements. Four fetuses were studied as neonates immediately after spontaneous term delivery and one was studied as a normal fetus in utero. Data from these preparations were augmented with seven sets of previously reported data from normal fetuses in utero for analysis. Linear least-squares regression analysis demonstrated that inferior caval vein flow into the right atrium was inversely related to right atrial pressure. This flow could not be demonstrated to depend on the velocity of blood in the inferior caval vein. Non-linear least-squares regression analysis of foramen ovale flow as a function of a power of the flow in the inferior caval vein revealed that the square of the velocity of blood in the inferior caval vein predicted foramen ovale flow. Of the two forces that determine foramen ovale flow in the fetus, pressure difference and kinetic energy, the latter was far larger than the former. These results support the theory that the fetal foramen ovale is maintained in an open position by the kinetic energy of the blood in the inferior caval vein.
对八只长期植入仪器的胎儿和新生羔羊测量了左右心房压力。采用电磁流量传感器和微球技术相结合的方法测量血流量。在测量过程中,三只胎儿在子宫内进行了通气。四只胎儿在足月自然分娩后立即作为新生儿进行研究,一只作为正常胎儿在子宫内进行研究。这些实验准备的数据与七组先前报道的正常子宫内胎儿的数据相结合进行分析。线性最小二乘回归分析表明,下腔静脉流入右心房的血流量与右心房压力呈负相关。未证实这种血流量取决于下腔静脉中的血流速度。对卵圆孔血流量作为下腔静脉血流功率函数的非线性最小二乘回归分析表明,下腔静脉中血流速度的平方可预测卵圆孔血流量。在决定胎儿卵圆孔血流量的两种力量中,压力差和动能,后者远大于前者。这些结果支持了胎儿卵圆孔通过下腔静脉中血液的动能保持开放状态的理论。