Morrison F K, Patel N B, Howie P W, Mires G J, Herd R M
Department of Obstetrics and Gynaecology, Ninewells Hospital and Medical School, Dundee, UK.
Early Hum Dev. 1995 Aug 18;42(3):155-68. doi: 10.1016/0378-3782(95)01646-k.
To define the effects of acid base status at delivery on neonatal cerebral artery flow velocity waveform patterns obtained using Doppler ultrasound during the first week of life, a longitudinal comparative study of neonates born at term with and without evidence of metabolic acidosis in the umbilical artery was undertaken. Eighty-two appropriate for gestational age infants delivered after uncomplicated pregnancies with non-acidotic umbilical artery blood gases and in whom no neonatal complications were noted were studied to establish reference values of neonatal cerebral arterial vascular resistance index (RI) in normal term infants during the first week of life. A further 189 infants were grouped according to the presence and severity of metabolic acidosis at delivery, and also the presence of high risk features in the antenatal period. In the normal non-acidotic infants, over the first 24 h of life, there was a significant fall in the cerebral arterial resistance index (RI) in all the vessels examined, after which a steady state value was attained with no significant changes in vascular resistance index being noted during the remainder of the study period. The fall in RI between 12 and 24 h of age was consistent in all study groups. Infants with metabolic acidosis at delivery had blood flow patterns compatible with decreased resistance to flow in both anterior and middle cerebral arteries which persisted throughout the first week of life. This reduction in cerebral vascular resistance was most marked in those infants with severe metabolic acidosis. The majority of severely acidotic infants had a benign clinical outcome in the first week of life and all infants had normal cerebral ultrasound scans during the neonatal period. These findings suggest that metabolic acidosis at birth is associated with changes in neonatal cerebral arterial vascular resistance during the first week of life, and in the presence of benign clinical course the significance of this observation with regard to neurodevelopmental outcome requires evaluation.
为了确定分娩时酸碱状态对出生后第一周使用多普勒超声获得的新生儿脑动脉血流速度波形模式的影响，我们对足月出生、脐动脉有无代谢性酸中毒证据的新生儿进行了一项纵向对比研究。研究了82例孕周适宜、妊娠过程无并发症、脐动脉血气无酸中毒且未发现新生儿并发症的婴儿，以确定正常足月婴儿出生后第一周脑动脉血管阻力指数（RI）的参考值。另外189例婴儿根据分娩时代谢性酸中毒的有无和严重程度，以及产前是否存在高危特征进行分组。在正常无酸中毒的婴儿中，出生后的前24小时内，所有检测血管的脑动脉阻力指数（RI）均显著下降，之后达到稳定状态，在研究期的剩余时间内血管阻力指数无显著变化。所有研究组在12至24小时龄之间RI的下降是一致的。分娩时患有代谢性酸中毒的婴儿，其大脑前动脉和中动脉的血流模式与血流阻力降低相符，且在出生后的第一周内持续存在。这种脑血管阻力的降低在那些患有严重代谢性酸中毒的婴儿中最为明显。大多数严重酸中毒的婴儿在出生后的第一周临床结局良好，所有婴儿在新生儿期的脑超声扫描均正常。这些发现表明，出生时的代谢性酸中毒与出生后第一周新生儿脑动脉血管阻力的变化有关，在临床过程良好的情况下，这一观察结果对神经发育结局的意义需要评估。
