Connors G, Hunse C, Gagnon R, Richardson B, Han V, Rosenberg H
St. Joseph's Health Centre, Department of Obstetrics and Gynecology, University of Western Ontario, London, Canada.
Pediatr Res. 1992 Jun;31(6):649-52. doi: 10.1203/00006450-199206000-00022.
The temporal relationship between changes in cerebral Doppler flow velocity wave forms, ductal patency, blood gases, and blood pressure during the transition from intrauterine to newborn life was assessed longitudinally in 16 healthy term fetuses and newborns. Doppler flow velocity wave forms were obtained from fetal cerebral arteries (anterior cerebral, internal carotid, and basilar) before birth, within 8 h after birth, and again at 24 and 48 h after birth. The resistance index was used as a measure of vascular resistance. The resistance index of the cerebral arteries studied increased significantly between the antenatal and 8-h study periods. This was followed by a significant decrease below fetal levels by the 24-h study period, with little change thereafter. We conclude that in the newborn human, as in the newborn lamb, the transition from fetal to immediate newborn life is associated with an increase in cerebral vascular resistance and thus a decrease in cerebral blood flow in response to the increase in arterial oxygenation. The subsequent decrease in the cerebral resistance index between 8 and 24 h of life cannot be explained by a loss of ductal shunting nor by associated changes in newborn blood gases or blood pressure, but may rather reflect a remodeling of the circulation due to impedance matching.
对16例健康足月儿及新生儿从宫内到新生儿期的过渡过程中脑多普勒血流速度波形、导管通畅情况、血气及血压变化之间的时间关系进行了纵向评估。在出生前、出生后8小时内、出生后24小时及48小时获取胎儿脑动脉（大脑前动脉、颈内动脉及基底动脉）的多普勒血流速度波形。阻力指数用作血管阻力的指标。所研究的脑动脉阻力指数在产前与8小时研究期之间显著增加。随后在24小时研究期时显著降至低于胎儿水平，此后变化不大。我们得出结论，在新生儿人类中，如同新生羔羊一样，从胎儿到即刻新生儿期的过渡与脑血管阻力增加相关，从而因动脉氧合增加导致脑血流量减少。出生后8至24小时脑阻力指数随后的降低无法用导管分流的丧失或新生儿血气及血压的相关变化来解释，而可能反映了由于阻抗匹配导致的循环重塑。
