Blood lactate at birth as result of activated anaerobic glycolysis is a marker of perinatal asphyxia.
Aim: To evaluate the dynamics of blood lactate, pH and base excess (BE) as a tool for assessing the severity of fetal hypoxia and predicting neonatal outcome.
Methods: 79 neonates (> or = 34 gestational weeks) were included and followed up until discharge: 43 with pathologic fetal hearth rate patterns and/or 1-minute Apgar score < 7 ("asphyxia group"); 36 without obstetric or clinical signs of asphyxia (control group). Samples from umbilical artery (u.a.), capillary blood at 2h and 12-24 h after birth were analyzed for blood lactate, pH and BE.
Results: Lactate value (u.a.) was significantly higher (5.3 +/- 3.4 mmol/l), pH and BE were lower (7.29 +/- 0.05 and -14.1 +/- 5.9 mmol/l) in the "asphyxia group" compared to the control group (2.7 +/- 1.2 mmol/l, 7.29 +/- 0.05 and -5.9 +/- 3.3 respectively). The 2 h lactate-values increased significantly in infants with asphyxia (6,.7 +/- 4.7) compared to the controls (3.2 +/- 1.1), the 12-24 h values were reduced in the main group (4.6 +/- 1.5) and without changes in the controls (3.2 +/- 0.88). Values of pH and BE at 2 h and 12-24 h increased progressively in both groups without significant differences between them. Hypoxic-ischemic encephalopathy (HIE) stage II-III was observed in infants with u.a. pH < 7.05, BE < -15 if u.a. lactate was high and progressively increased in next 2 h.
Conclusions: High u.a. lactate values correlate with low pH and BE and is a reliable tool for assessing the severity of fetal asphyxia. Increasing lactate concentration after birth is better predictor of severe HIE.