Fu Jing, Olofsson Per
Department of Obstetrics and Gynecology, Malmö University Hospital, Lund University, S-205 02 Malmö, Sweden.
Early Hum Dev. 2007 Sep;83(9):607-12. doi: 10.1016/j.earlhumdev.2007.01.011. Epub 2007 Feb 27.
To explore middle cerebral artery (MCA) and anterior cerebral artery (ACA) blood flow responses to superimposed acute hypoxemia in growth-restricted fetuses with and without established brain-sparing flow during basal conditions.
47 term fetuses suspected of growth restriction were exposed to an oxytocin challenge test with simultaneous cardiotocography and Doppler velocimetry in the umbilical artery, MCA and ACA. The MCA-to-ACA pulsatility index (PI) ratio was calculated during basal conditions, contractions and relaxations. Basal brain-sparing flow was defined as an MCA-to-umbilical artery PI ratio of<1.08, de novo brain-sparing flow in the MCA as an MCA PI decrease with> or =1 standard deviation during uterine contractions or relaxations compared with basal measurements, and de novo brain-sparing flow in the ACA as an ACA PI decrease with > or =1 standard deviation. Non-parametric statistical tests were used with P<0.05 considered significant.
MCA and ACA PI were both significantly lower in the brain-sparing flow group (N=8) during basal conditions (P< or =0.01). During the oxytocin challenge test, MCA and ACA PI both decreased in the non-brain-sparing flow group (N=39) (P< or =0.02) but not in the brain-sparing flow group (P> or =0.4). The MCA-to-ACA PI ratio remained unchanged in both groups. de novo brain-sparing flow calculations revealed no preferential flow to any cerebral artery.
Cerebral circulatory responses to acute hypoxemia are synchronized in the middle and anterior cerebral arteries without any preferential regional flow distribution.
探讨在基础状态下，有无脑保护血流的生长受限胎儿大脑中动脉（MCA）和大脑前动脉（ACA）对叠加急性低氧血症的血流反应。
47例疑似生长受限的足月胎儿接受催产素激发试验，同时进行胎心监护及脐动脉、MCA和ACA的多普勒血流速度测定。在基础状态、宫缩期和松弛期计算MCA与ACA搏动指数（PI）比值。基础脑保护血流定义为MCA与脐动脉PI比值<1.08，MCA新出现的脑保护血流为宫缩期或松弛期MCA的PI较基础测量值下降≥1个标准差，ACA新出现的脑保护血流为ACA的PI下降≥1个标准差。采用非参数统计检验，P<0.05为有统计学意义。
基础状态下，脑保护血流组（N=8）的MCA和ACA的PI均显著降低（P≤0.01）。在催产素激发试验中，非脑保护血流组（N=39）的MCA和ACA的PI均下降（P≤0.02），而脑保护血流组未下降（P≥0.4）。两组的MCA与ACA的PI比值均保持不变。新出现的脑保护血流计算结果显示，未出现向任何脑动脉的优先血流。
大脑中动脉和大脑前动脉对急性低氧血症的脑循环反应是同步的，没有任何优先的区域血流分布。
