Wiberg Nana, Källén Karin, Olofsson Per
Department of Obstetrics and Gynecology, Malmö University Hospital, University of Lund, S-205 02, Malmö, Sweden.
Early Hum Dev. 2006 Sep;82(9):583-9. doi: 10.1016/j.earlhumdev.2005.12.005. Epub 2006 Feb 10.
To investigate respiratory and metabolic components of gestational age-dependent umbilical cord blood gas changes.
Cord blood gases were determined in 1336 vigorous singletons with uncomplicated cephalic vaginal delivery at 37-43 weeks. Linear regression analysis and non-parametric statistics were used with a P < 0.05 being significant.
Gestational age correlated negatively with arterial pH and HCO3- and positively with pCO2 and base deficit. Venous blood showed corresponding changes except for pCO2, which was independent of gestational age. Arterial pCO2, but not venous, correlated positively with birthweight deviation from the mean. The fractional fetal CO2 production per birthweight unit and the fractional placental CO2 clearance per placental weight unit were not correlated with gestational age.
A mixed respiratory and metabolic cord blood acidemia develops with advancing gestational age. The respiratory component depends on an increased 'CO2 load' from the growing fetus and not on deterioration of placental gas exchange. The etiology of the metabolic component is yet unknown.
研究胎龄依赖性脐血气变化的呼吸和代谢成分。
对1336例孕37 - 43周、头位阴道分娩、情况正常的单胎活产儿测定脐血气。采用线性回归分析和非参数统计，P < 0.05为有显著性差异。
胎龄与动脉血pH值和HCO3-呈负相关，与pCO2和碱缺失呈正相关。静脉血除pCO2外显示出相应变化，pCO2与胎龄无关。动脉血pCO2与出生体重偏离均值呈正相关，而静脉血则不然。每出生体重单位的胎儿CO2产生分数和每胎盘重量单位的胎盘CO2清除分数与胎龄无关。
随着胎龄增加，出现混合性呼吸和代谢性脐血酸血症。呼吸成分取决于不断生长的胎儿“CO2负荷”增加，而非胎盘气体交换恶化。代谢成分的病因尚不清楚。
