Blood lactate kinetics as biomarkers of MRI brain injury in neonates with hypoxic-ischemic encephalopathy

Background In neonates with hypoxic ischemic encephalopathy (HIE), early biomarkers are needed to enhance prognostic accuracy. We hypothesized that blood lactate kinetics correlate with magnetic resonance imaging (MRI) based brain injury severity. Methods In this prospective cohort study, neonates with HIE admitted to a tertiary neonatal intensive care unit underwent brain MRI within the first week of life. Injury severity was graded using a validated MRI scoring system, with neonates categorized into low severity (LS) or high severity (HS) groups based on the 75th percentile of the total score. Lactate kinetics were evaluated through peak lactate levels, time to lactate normalization (TLN), and area under the curve (AUC). Associations between lactate kinetics and MRI scores were analyzed. Results Among forty eight neonates, 83% underwent therapeutic hypothermia. Compared with the LS group, the HS group had more seizures, higher Thompson and Sarnat scores, and more abnormal neurological exams at discharge. Peak lactate was higher in the HS group (p=0.02) and correlated with MRI grey matter subscores (p=0.004). Lactate AUC and TLN were positively associated with MRI total and grey matter scores (all p<0.01). Conclusion Lactate kinetics are associated with MRI assessed brain injury severity in HIE and may help stratification to tailor therapeutic strategies.