Threshold value of lactic acid and buffer excess in umbilical cord arterial blood gas during neonatal asphyxia

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 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 3.97 mmol/L and ≤-6 mmol/L, respectively. Key words: Umbilical artery; Blood gas analysis; Lactic acid; Buffuer excess; Newborn