Fetal Stress as a Cause of Fetal Brain Damae

据报道，脐带闭塞与围产期脑损伤密切相关。我们假设反复脐带闭塞导致胎儿心功能障碍，这可能与脑灌注不足和损伤有关。本研究旨在探讨反复脐带闭合对胎羊心功能的影响。我们在超声引导下将导尿管插入心脏左心室，记录11只近期胎羊的心脏左心室压力-容积曲线。脐带完全闭合5次，每次60秒，5次，每次90秒，5次，每次120秒。在整个实验过程中，脐带闭塞显著减少了脑卒中容量。阻断间隔90秒时，胎儿心脏收缩力和心输出量较对照组显著增加。然而，在120秒的闭塞间隔期间，卒中量明显下降。推测这些胎儿心功能的改变可能与反复脐带闭塞引起的缺氧、酸中毒和儿茶酚胺分泌有关。

It has been reported that umbilical cord occlusion is closely related to perinatal brain damage. We hypothesized that repeated umbilical cord occlusions cause fetal cardiac dysfunction, which is possibly related to brain hypoperfusion and injury. The purpose of this study is to investigate the effect of repeated umbilical cord occlusions on cardiac functions in fetal sheep.We inserted a conductance catheter into the left ventricle of the heart under ultrasound guidance to record pressur-volume curves of the left ventricle of the heart in 11 near-term fetal sheep. Umbilical cord was completely occluded five times for 60 seconds, five times for 90 seconds and five times for 120 seconds.Umbilical cord occlusions reduced stroke volume significantly throughout the experiments. During intervals of 90 seconds occlusion, fetal heart contractility and cardiac output increased Significantly compared with the control levels. However, stroke volume decreased significantly during intervals of 120 seconds occlusion. It is speculated that these changes in fetal cardiac function could be related to hypoxia, acidosis, and catecholamine secretion induce by repeated cord occlusions.