Wiberg Nana, Källén Karin, Olofsson Per
Perinatal Revision South Register, Lund, Sweden.
Am J Obstet Gynecol. 2006 Dec;195(6):1651-6. doi: 10.1016/j.ajog.2006.05.043. Epub 2006 Sep 25.
The purpose of this study was to explore the influences of gestational age, the choice of fetal fluid compartment, and the algorithm for calculation on the estimation of the base deficit in umbilical cord arterial blood at birth.
From 1995 to 2002, cord arterial blood gases and obstetric data were available for 43,551 newborn infants at 37+ weeks of gestation (cohort I). The mean base deficit in blood and the base deficit in extracellular fluid were estimated from pH and PCO2 values in 28,213 newborn infants with a 5-minute Apgar score of > or = 9 (cohort II) with the use of 3 different calculation algorithms (base deficit in blood, base deficit in extracellular fluid [A], and base deficit in extracellular fluid [B]).
In cohort II, the base deficit in blood, the base deficit in extracellular fluid (A), and the base deficit in extracellular fluid (B) increased with advancing gestational age (linear regression; P < .0001). The curves run almost parallel, with the base deficit in blood being higher than the base deficit in extracellular fluid (A) and (B). With the use of receiver operating characteristic curves in cohort I, the area under curve to indicate a 5-minute Apgar score of < 7 and < 4 showed the area under curve-pH to be greater than the area under curve-base deficit in extracellular fluid (A) and (B), the area under curve-base deficit in blood to be greater than the area under curve-base deficit in extracellular fluid (A) and (B) for a 5-minute Apgar score of < 7, and the area under curve-base deficit in blood to be greater than the area under curve-base deficit in extracellular fluid (A) and (B) for an Apgar score of < 4. The cutoffs with highest sensitivity and lowest false-positive rate for a 5-minute Apgar score of < 7 and < 4 were, for both scores, a pH value of 7.15, a base deficit in blood of 10 mmol/L, a base deficit in extracellular fluid (A) of 8 mmol/L, and a base deficit in extracellular fluid (B) of 6 mmol/L.
The calculated values of the base deficit in umbilical cord arterial blood are influenced decisively by gestational age, the choice of fetal fluid compartment, and the calculation algorithms that are used. The power of the base deficit to indicate neonatal distress depends on the choices of fluid compartment and the algorithm that is used to calculate the base deficit.
本研究旨在探讨胎龄、胎儿体液腔室的选择以及计算算法对出生时脐动脉血碱缺失估计值的影响。
1995年至2002年，有43551例孕37周以上新生儿（队列I）的脐动脉血气和产科数据。使用3种不同的计算算法（血液碱缺失、细胞外液碱缺失[A]和细胞外液碱缺失[B]），根据28213例5分钟Apgar评分≥9分的新生儿（队列II）的pH值和PCO2值，估计血液碱缺失和细胞外液碱缺失。
在队列II中，血液碱缺失、细胞外液碱缺失（A）和细胞外液碱缺失（B）随胎龄增加而升高（线性回归；P<.0001）。这些曲线几乎平行，血液碱缺失高于细胞外液碱缺失（A）和（B）。在队列I中使用受试者工作特征曲线，用于表示5分钟Apgar评分<7分和<4分的曲线下面积显示，曲线下面积-pH大于曲线下面积-细胞外液碱缺失（A）和（B）；对于5分钟Apgar评分<7分，曲线下面积-血液碱缺失大于曲线下面积-细胞外液碱缺失（A）和（B）；对于Apgar评分<4分，曲线下面积-血液碱缺失大于曲线下面积-细胞外液碱缺失（A）和（B）。对于5分钟Apgar评分<7分和<4分，具有最高敏感性和最低假阳性率的截断值，对于这两个评分，pH值均为7.15，血液碱缺失为10 mmol/L，细胞外液碱缺失（A）为8 mmol/L，细胞外液碱缺失（B）为6 mmol/L。
脐动脉血碱缺失的计算值受胎龄、胎儿体液腔室的选择以及所使用的计算算法的决定性影响。碱缺失用于指示新生儿窘迫的效能取决于体液腔室的选择和用于计算碱缺失的算法。
