The prognostic value of the level of lactate in umbilical cord blood in predicting complications of neonates with meconium aspiration syndrome

Background: In spite of significant advances in therapeutic, diagnostic and even medical modalities, meconium management continues to be a concern for management. It has been recently assumed that trace of lactate in both serum and urine can be a sign of the asphyxia in neonates. However, no study has been done on the prognostic value of increasing lactate concentration in umbilical cord blood for predicting the outcomes of meconium aspiration syndrome (MAS), which was our aim in this study. Methods: Thin cross-sectional study was performed on 150 neonates suffering meconium aspiration syndrome who were admitted to Akbar Abadi hospital in Tehran between 2016 and 2018. Samples of umbilical cord blood were extracted from neonates and sent to the reference laboratory to measure lactate level as well as arterial blood gas analysis. The neonatal characteristics as well as postdelivery complications were also collected by reviewing the hospital recorded files. Results: Thick meconium stained amniotic fluid (TKMSF) was found in 40.0% and thin meconium stained amniotic fluid (TNMSF) in 60.0%. The mean level of lactate was significantly higher in those neonates with morbidities including pulmonary hemorrhage, persistent pulmonary hypertension of the neonate (PPHN), intraventricular hemorrhage (IVH), and respiratory failure requiring ventilation support. According to the ROC curve analysis, increasing lactate in umbilical cord blood could predict occurrence of pulmonary hemorrhage (AUC = 0.885), PPHN (AUC = 0.832), IVH (AUC = 0.898), and requiring ventilation (AUC = 0.833). Comparing the two groups with TKMSF and TNMSF showed higher gestational age, lower Apgar score, lower BE, higher PCO2, lower PO2, lower PH as well as higher serum lactate. In this regard and using the ROC curve analysis (Table 4), increased lactate could effectively discriminate TKMSF from TNMSF (AUC = 0.998) with the best cut-off value of 4.10. Conclusion: The increase in lactate in the umbilical cord blood (>4.1 mmol/L with high sensitivity and specificity) can distinguish between thick meconium and thin meconium forms in amniotic acid and thus can determine the severity of MAS. Also, increasing serum lactate levels is an accurate indicator for predicting complications such as pulmonary hemorrhage, PPHN, IVH, and need for ventilation in newborns with this syndrome. This diagnostic accuracy is even beyond the usual markers for arterial gas analysis, such as PH, PCO2, PO2 and BE.