17 - Duration of Normalization of Blood Lactate Levels Increases the Prediction of Clinical Outcomes of Infants Treated with Therapeutic Hypothermia for Hypoxic Ischemic Encephalopathy

Poster Number: 17
Publication Number: 17.614

Background: Neonatal hypoxic–ischemic encephalopathy (HIE) is one of the most common causes of severe neurological deficit in children. The severity of lactic acidemia reflects the degree of fetal hypoxia–ischemia, but a single lactate measurement gives no definitive information regarding the duration of asphyxia. It is currently unknown if prolonged duration of normalization of lactate levels is associated with poor neurodevelopmental outcomes in infants with HIE undergoing therapeutic hypothermia.

Objective: The objective of this study is to assess the association between duration of blood lactate normalization, severity of lactic acidosis, and short-term outcomes in neonates with HIE treated with therapeutic hypothermia (TH).

Design/Methods: This is a retrospective, single-center cohort study of HIE neonates (gestational age ≥36 weeks) who underwent TH between January 2012 and December 2022. Neonates with lethal congenital malformations, chromosomal anomalies, or need for extracorporeal membrane oxygenation were excluded.

Results: Overall, 151 patients were studied, with 56.3% males, 60.3% cesarean section delivery, 42.4/14.6% moderate/severe HIE, and median gestational age at 39.3 weeks. Of all neonates, 66.7% of patients’ lactate levels were normalized in the first 24 hours. Only 11.3% of neonates had background EEG normalization in the first 24 hours of life. Initial lactate levels of >10 mmol/L was associated with abnormal EEG background in the first 24 hours of life (p < 0.001), and seizures (p=0.002). The duration of lactate normalization ≥48 hours was associated with higher level of background EEG abnormality in the first 24 hours of life (p=0.001) and higher likelihood of seizures (p < 0.001). Besides, the duration of lactate normalization ≥48 hours were associated with higher likelihood of abnormal MRI results, mechanical ventilation support and NICU mortality, as well as longer days ventilation support, full enteral (PO) feeds, and NICU stay (all p< 0.05).

Conclusion(s): Duration of blood lactate normalization ≥48 hours was associated with increased seizure burden, abnormal EEG and MRI findings, prolonged mechanical ventilation, and increased mortality in infants with HIE who underwent TH.