Itskovitz J, LaGamma E F, Rudolph A M
Am J Physiol. 1987 Jan;252(1 Pt 2):H100-9. doi: 10.1152/ajpheart.1987.252.1.H100.
We used the radionuclide microsphere technique in nine fetal lambs to examine the effect of partial cord compression on distribution of cardiac output and O2 delivery to fetal organs and venous flow patterns. With a 50% reduction in umbilical blood flow the fraction of fetal cardiac output distributed to the brain, heart, carcass, kidneys, and gastrointestinal tract increased. Pulmonary blood flow fell. O2 delivery to the brain and myocardium was maintained but was reduced to peripheral, renal, and gastrointestinal circulations. Hepatic blood flow decreased and O2 delivery fell by 75%. The proportion of umbilical venous blood passing through the ductus venosus increased from 43.9 to 71.8%. The preferential distribution of ductus venosus blood flow through the foramen ovale was enhanced (29.4 vs. 47.2%) and the proportion of O2 delivery to upper body organs derived from the ductus venosus increased (33.2 vs. 49.4%). Abdominal inferior vena caval blood flow increased, and it was also preferentially distributed through the foramen ovale (21.9 vs. 44.2%) and constituted the major fraction of the arterial blood supply to the upper body organs (16.5 vs. 36.4%). Thus cord compression modified the distribution of cardiac output and the patterns of venous returns in the fetus. This pattern of circulatory response differs from that observed with other causes of reduced O2 delivery.
我们在9只胎羊中采用放射性核素微球技术，以研究部分脐带受压对心输出量分布、胎儿各器官氧输送及静脉血流模式的影响。当脐血流量减少50%时，分配到脑、心脏、躯体、肾脏及胃肠道的胎儿心输出量比例增加。肺血流量下降。脑和心肌的氧输送得以维持，但外周、肾脏及胃肠道循环的氧输送减少。肝血流量减少，氧输送下降75%。经静脉导管的脐静脉血比例从43.9%增至71.8%。经卵圆孔的静脉导管血流优先分布增强（29.4%对47.2%），来自静脉导管的氧输送至上身器官的比例增加（33.2%对49.4%）。下腔静脉腹部血流增加，且也优先经卵圆孔分布（21.9%对44.2%），并构成上身器官动脉血供应的主要部分（16.5%对36.4%）。因此，脐带受压改变了胎儿的心输出量分布及静脉回流模式。这种循环反应模式不同于因其他导致氧输送减少的原因所观察到的模式。
