Rudolph Abraham M
Department of Pediatrics and Cardiovascular Research Institute, University of California, San Francisco, California 94143, USA.
Pediatr Res. 2007 Mar;61(3):375-80. doi: 10.1203/pdr.0b013e318030d5b9.
Fetuses with transposition and abnormalities of the foramen ovale and/or ductus arteriosus detected by ultrasound may develop severe hypoxemia postnatally. Higher than normal oxygen content in the pulmonary artery has been considered to be responsible. Patterns of blood flow in the normal fetus and the fetus with aortopulmonary transposition were reviewed. Well-oxygenated ductus venosus is preferentially directed through the foramen ovale into the left atrium. Normally this produces a higher oxygen content in the ascending aorta. In the fetus with transposition, pulmonary arterial oxygen content is higher. Pulmonary vascular resistance is decreased and the ductus arteriosus constricted. Increased pulmonary venous return to the left atrium tends to close the foramen ovale. Changes are more likely in the last trimester because sensitivity of the pulmonary circulation and ductus arteriosus increases. Severe ductus arteriosus constriction could result in pulmonary arterial hypertension and increased pulmonary arteriolar smooth muscle development. Variability of responses could be related to the proportion of umbilical venous blood passing through the ductus venosus. It is proposed that, in fetuses with evidence of abnormalities of the ductus arteriosus and/or the foramen ovale, methods to occlude the ductus venosus be developed to avoid progressive changes.
超声检测发现卵圆孔和/或动脉导管存在转位及异常的胎儿，出生后可能会出现严重低氧血症。肺动脉中氧含量高于正常水平被认为是其原因。回顾了正常胎儿和大动脉转位胎儿的血流模式。氧合良好的静脉导管优先通过卵圆孔进入左心房。正常情况下，这会使升主动脉中的氧含量升高。在大动脉转位的胎儿中，肺动脉的氧含量更高。肺血管阻力降低，动脉导管收缩。肺静脉回流至左心房增加往往会使卵圆孔关闭。在妊娠晚期变化更可能发生，因为肺循环和动脉导管的敏感性增加。严重的动脉导管收缩可能导致肺动脉高压，并增加肺小动脉平滑肌的发育。反应的变异性可能与通过静脉导管的脐静脉血比例有关。有人提出，对于有动脉导管和/或卵圆孔异常证据的胎儿，应开发封堵静脉导管的方法，以避免病情进展。
