Objective: To determine if neonatal serum biomarkers representing different pathways of injury differ for cases of HIE of unknown cause to gain insight into timing and mechanism of injury.
Study design: In this cohort of all neonates with HIE admitted to our NICU, newborns with sentinel events were compared to those without during the 1st 3 days of life. Discard neonatal blood during the 1st 3 days of life was used for analysis.
Results: Of 277 babies with HIE treated with whole-body hypothermia, 190 (68.6%) had blood available for biomarker analysis. In total, 71 (37.4%) were born within our system, and 119 (62.6%) were transferred in from outside hospitals. Of these babies, 77 (40.5%) had a sentinel event and 113 (59.6%) had no sentinel event. Although the degree of metabolic acidosis was similar, repeated measures analysis showed that during the initial 3 days of life neonates born with HIE in the absence of sentinel events had 41.4% decreased VEGF (p = 0.027) and 62.5% increased IL-10 serum concentrations (p = 0.005).
Conclusion: These changes indicate that neonatal HIE in the absence of sentinel events is not related to an unrecognized acute intrapartum event and is possibly related to chronic hypoxia of lower severity or recovery from a remote event.