Significance of umbilical artery blood gas on diagnosis of neonatal asphyxia

Objective To study the reference range of umbilical artery blood gas and the significance of umbilical artery blood pH on the diagnosis of neonatal asphyxia. Methods Five thousand six hundred and eleven live-births new born in our hospital were consecutively enrolled. The following five items related to birth asphyxia were recorded including antepartum high-risk factors, Apgar scores, umbilical artery blood pH, organ damage, and differential diagnosis on the causes of low Apgar score. Reference range of umbilical artery blood gas, the correlations between the umbilical artery blood pH and the other items were analysed. Results The reference range of umbilical artery blood gas ((x|-)±2s) were pH 7.00 - 7.40, PaO2 0.34 - 6.10 kPa, PaCO2 3.43 - 10.03 kPa, BE 1.5 - - 18. 5 mmol/L. The umbilical artery blood pH was negatively correlated with organ damage (r = - 0. 99,P0. 01). The sensitivity on asphyxia diagnosis of antepartum high-risk factors, Apgar score,organ injury were all 100%, and the specificity were 1. 7%, 50% and 72. 6%, respectively. When combined with pH7. 00 in cord blood, the sensitivity and specificity was 37. 7%,100%. Conclusions Neonatal asphyxia diagnosis based on Apgar score alone may result in misdiagnosis, the specificity will be increased when combined with the umbilical artery blood pH7. 00. Umbilical artery blood pH can be complement and should be as one of the criterion of neonatal asphyxia diagnosis.