The Significance of umbilical artery blood pH, base deficit, bicarbonate, and lactate levels for cerebral blood circulation changes and hypoxic-ischemic encephalopathy in full-term neonates

Abstract

Purpose of study: The umbilical artery blood pH, base deficit (BE), bicarbonate, and lactate levels–the main indicators of fetal distress. The aim of the study was to evaluate the significance of following indicators for cerebral blood circulation changes, and hypoxic-ischemic encephalopathy (HIE) in full-term infants. Materials and methods: The prospective cross-sectional study was performed at the Department of Neonatology, Lithuanian University of Health Sciences. The studied group consisted of 58 full-term neonates who experienced perinatal asphyxia or hypoxia. Immediately after birth was analysed umbilical artery blood pH, BE, bicarbonate, and lactate levels. During the first five days of life blood circulation in the anterior cerebral arteries was measured, and evaluated clinical signs of HIE using the modified Sarnat and Sarnat scale. The comparison between the HIE groups was performed by applying the parametric and nonparametric ANOVA analysis and the non-parametric Kruskal–Wallis (χ2 – chi square) criterion and Kendal (r) criterions. Correlation analysis was applied to determine the correlation of blood circulation parameters with pH, BE, bicarbonate and lactate levels. Results: Mean Vs values in ACA on day 2 were significantly (p = 0.02) lower when umbilical artery blood BE was ≤−12 mmol/L, and bicarbonate levels were <19 mmol/L. We did not find any statistically significant differences in mean Vd and RI values in ACA between pathological index groups of umbilical artery blood pH, BE, bicarbonate and lactate levels. Significantly lower pH values were detected in the umbilical artery blood of neonates with more severe stages of HIE (r = 0.5; p < 0.001). Conclusions: Umbilical artery blood pH correlated with the stage of HIE. Bicarbonate and BE levels in full-term infants influenced changes in cerebral blood circulation