Lan J, Hunter C J, Murata T, Power G G
Center for Perinatal Biology, School of Medicine, Loma Linda University, Loma Linda, California 92350, USA.
J Appl Physiol (1985). 2000 Sep;89(3):1065-71. doi: 10.1152/jappl.2000.89.3.1065.
The purpose of this study was to devise a means to use laser-Doppler flowmetry to measure cerebral perfusion before birth. The method has not been used previously, largely because of intrauterine movement artifacts. To minimize movement artifacts, a probe holder was molded from epoxy putty to the contour of the fetal skull. A curved 18-gauge needle was embedded in the holder. At surgery, the holder, probe, and skull were fixed together with tissue glue. Residual signals were recorded after fetal death and after maternal death 1 h later. These averaged <5% of baseline flow signals, indicating minimal movement artifact. To test the usefulness of the method, cerebral flow responses were measured during moderate fetal hypoxia induced by giving the ewes approximately 10% oxygen in nitrogen to breathe. As fetal arterial PO(2) decreased from 21.1 +/- 0.5 to 10.7 +/- 0.4 Torr during a 30-min period, cerebral perfusion increased progressively to 56 +/- 8% above baseline. Perfusion then returned to baseline levels during a 30-min recovery period. These responses are quantitatively similar to those spot observations that have been recorded earlier using labeled microspheres. We conclude that cerebral perfusion can be successfully measured by using laser-Doppler flowmetry with the unanesthetized, chronically prepared fetal sheep as an experimental model. With this method, relative changes of perfusion from a small volume of the ovine fetal brain can be measured on a continuous basis, and movement artifacts can be reduced to 5% of measured flow values.
本研究的目的是设计一种方法，利用激光多普勒血流仪在出生前测量脑灌注。该方法以前尚未使用过，主要是因为存在子宫内运动伪影。为了尽量减少运动伪影，用环氧油灰根据胎儿颅骨轮廓模制了一个探头固定器。一根弯曲的18号针嵌入固定器中。在手术时，固定器、探头和颅骨用组织胶水固定在一起。在胎儿死亡后以及1小时后母体死亡后记录残留信号。这些信号平均<基线血流信号的5%，表明运动伪影最小。为了测试该方法的实用性，在给母羊吸入约10%氮气中的氧气诱导中度胎儿缺氧期间测量脑血流反应。在30分钟内，随着胎儿动脉血氧分压从21.1±0.5降至10.7±0.4 Torr，脑灌注逐渐增加至比基线高56±8%。然后在30分钟的恢复期内灌注恢复到基线水平。这些反应在数量上与早期使用标记微球记录的点观察结果相似。我们得出结论，以未麻醉、长期准备的胎儿绵羊为实验模型，使用激光多普勒血流仪可以成功测量脑灌注。通过这种方法，可以连续测量绵羊胎儿小体积脑区灌注的相对变化，并且运动伪影可以减少到测量血流值的5%。
