Threshold value of lactic acid and buffer excess in umbilical cord arterial blood gas during neonatal asphyxia / 中国小儿急救医学

ABSTRACT

Objective@#To study the threshold values of lactic acid (Lac)and buffuer excess (BE) when neonatal umbilical arterial blood gas is at pH <7.20.@*Methods@#A total of 2 518 pregnant women admitted in Beijing New Century Women and Children′s Hospital from January 2017 to February 2019 were enrolled.The general conditions in perinatal period and labor methods were counted.Umbilical cord arterial blood was immediately collected before the first cry of newborn and was detected on the Abbott I-STAT automatic blood gas analyzer from the United States, and then the umbilical arterial blood gas was measured.We analyzed the perinatal factors affecting umbilical arterial blood gas.We studied the threshold values of Lac and BE for neonal asphyxia by receiver operating characteristic curve.@*Results@#(1)Maternal anemia, Streptococcus agalactiae infection, precipitate labour, placenta abnormalities had no significant impact on neonatal umbilical artery blood gas.The Lac value in blood gas was higher in the group of premature rupture of fetal membranes and fetal intrauterine distress.The value of BE was lower in the group with premature rupture of fetal membranes and fetal distress (P<0.05). The Lac value in cesarean section group was the lowest[(1.79±1.25) mmol/L], while that in midwifery group was the highest[(4.45±1.58) mmol/L]. pH value was the lowest (7.25±0.07) in the midwifery group and the highest (7.31±0.06) in the cesarean section group.The value of BE was the lowest in the midwifery group[-(5.66±2.52) mmol/L], and the highest in the cesarean section group[-(2.99±2.28) mmol/L], with statistically significant differences among the three groups (P<0.05). (2) Multiple linear regression analysis showed that fetal delivery mode, fetal intrauterine distress, premature rupture of membranes, and gestational diabetes were the factors affecting Lac level in umbilical artery blood gas of newborns.Methods of delivery, intrauterine distress, premature rupture of membranes and placental abnormalities were the factors that affected the BE value of umbilical artery blood gas in newborns.(3) A total of 199 cases with pH value <7.2 were diagnosed as asphyxia, and the receiver operating characteristic curve of Lac and BE values of neonatal umbilical artery blood gas for the diagnosis of asphyxia was drawn.When Lac was >3.97 mmol/L, the sensitivity and specificity of the diagnosis of asphyxia were 0.864 and 0.791, respectively.When BE was ≤-6 mmol/L, the diagnostic sensitivity and specificity of asphyxia were 0.613 and 0.756, respectively.@*Conclusion@#Neonatal umbilical arterial blood gas is affected by many factors.The effect of accouche on umbilical arterial blood gas is large.When there is asphyxia with pH <7.2, the cut points of Lac and BE are >3.97 mmol/L and ≤-6 mmol/L, respectively.