Clinical value of lactate measurement and nucleated red blood cell counts in the placental segment of the umbilical vein of premature newborns for diagnosis of hypoxia-ischemia.

OBJECTIVE To evaluate the clinical value of lactate measurement and nucleated red blood cell (NRBC) counts when compared to base excess (BE) in the blood collected from the placental segment of the umbilical vein. METHODS 25 umbilical cords from premature babies were sampled after placental delivery and cord clamping. Babies were followed until discharge. Statistics involved linear regression, Spearman's correlation, ROC curves, and Fisher's exact test. RESULTS The relationship between lactate in the umbilical vein blood and pH and BE was significant (p < 0.0001). A 4.04 mmol/L lactate level showed a sensitivity of 62.5% and a specificity of 94.1% in detecting pH < 7.2 and BE < -10 mmol/L. NRBC counts were related to BE (p = 0.0095), but with a sensitivity of 37.5% and specificity of 82.4% in detecting BE < -10 mmol/L. CONCLUSIONS Lactate is a valuable marker of fetal hypoxia when sampled from placental segment veins. NRBC counts demonstrated low sensitivity for the detection of acidosis.