Itskovitz J, Goetzman B W, Rudolph A M
Am J Physiol. 1982 Apr;242(4):H543-8. doi: 10.1152/ajpheart.1982.242.4.H543.
The effect of acute hemorrhage (21.7 +/- 1.6%, mean +/- SE of the estimated blood volume) on the distribution of the umbilical venous return (UVR) and oxygen delivery to fetal organs (radionuclide microsphere technique) was studied in 10 chronically catheterized fetal lambs. Hemorrhage decreased UVR and total oxygen delivery to the fetus by 23 and 28%, respectively (P less than 0.001). A greater proportion of the UVR bypassed the liver through the ductus venosus (DV) (P less than 0.01). Consequently, DV blood flow was relatively maintained, and liver blood flow and oxygen delivery derived from the UVR decreased by 41 and 45%, respectively (P less than 0.002). The proportion of cardiac output constituted by DV blood increased by 30% (P less than 0.01). The changes in the distribution of the DV blood were similar to the changes in the distribution of cardiac output. As a result the proportion of organ blood flow and oxygen delivery derived from DV blood increased by 30% in both the upper and lower body organs. These studies show that fetal hemorrhage has a marked effect on the distribution of the UVR to the liver. The preferential distribution of the DV blood to the heart and brain is maintained but not enhanced. Our results indicate that changes in distribution of the DV-derived blood and oxygen following fetal hemorrhage is determined primarily by the responses of the arterial circulation, i.e., circulatory afterload.
在10只长期插管的胎羊中，研究了急性失血（估计血容量的21.7±1.6%，平均值±标准误）对脐静脉回流（UVR）分布以及胎儿器官氧输送（放射性核素微球技术）的影响。失血分别使UVR和胎儿的总氧输送减少了23%和28%（P<0.001）。更大比例的UVR通过静脉导管（DV）绕过肝脏（P<0.01）。因此，DV血流量相对维持，而源自UVR的肝血流量和氧输送分别减少了41%和45%（P<0.002）。由DV血液构成的心输出量比例增加了30%（P<0.01）。DV血液分布的变化与心输出量分布的变化相似。结果，上半身和下半身器官中源自DV血液的器官血流量和氧输送比例均增加了30%。这些研究表明，胎儿失血对UVR向肝脏的分布有显著影响。DV血液优先分布到心脏和大脑的情况得以维持但未增强。我们的结果表明，胎儿失血后源自DV的血液和氧分布的变化主要由动脉循环的反应决定，即循环后负荷。
