Umbilical cord blood lactate is associated with transient tachypnoea of the newborn in near-term and term neonates.

INTRODUCTION: Transient tachypnea of the newborn (TTN) is the main reason of admission to the neonatal intensive care unit (NICU). The aim of the study was to analyze the association of umbilical cord (UC) lactate with TTN. PATIENTS AND METHODS: Retrospective observational study in a level III NICU including infants born alive at or after 34 weeks. We fitted a multivariate logistic regression model for TTN diagnosis, adjusted for confounders, and assessed its diagnostic performance by means of the area under the curve (AUC) and the sensitivity, specificity, and predictive values at the best cut-off point. RESULTS: A total of 2120 neonates (50.7% male) with a median age of 39.5 weeks (IQR, 38.6-40.5) were included between August 2022 and December 2023, of whom 101 (4.8%) were preterm. In the total sample, 120 infants (5.7%) developed TTN. We found that UC lactate was independently associated with TTN (adjusted OR, 1.365; 95% CI, 1.246-1.495), with an AUC of 0.61 (95% CI, 0.56-0.67). The best cut-off point was 5.9 mmol/L, with a sensitivity of 34.5% (95% CI, 26.0-43.0), a specificity of 84.9% (95% CI, 83.3-86.5), a negative predictive value of 95.6% (95% CI, 94.7-96.5), and a positive predictive value of 12.0% (95% CI, 8.6-15.4). CONCLUSION: Umbilical cord blood lactate was independently associated with TTN in near-term and term neonates Although its diagnostic performance makes its use in isolation inapropriate for decision-making, it can be considered as an additional biomarker in the global evaluation of newborn infants in the delivery room.