Nucleated red blood cells in neonates with hypoxic ischaemic encephalopathy treated with hypothermia: A worthwhile prognostic biomarker for clinicians in LMIC?

Abstract

Background. Neonatal hypoxic ischaemic encephalopathy (HIE) is a leading cause of term neonatal death worldwide, with a higher incidence in low-to middle-income settings. Objective. To investigate whether nucleated red blood cell (nRBC) counts could predict severity of HIE and outcomes in term neonates treated with therapeutic hypothermia (TH). Methods. We conducted a retrospective sub-study at Tygerberg Hospital in Cape Town, South Africa. The review included all cooled neonates’ clinical records and blood samples from a National Health Laboratory Services database. One experienced neurodevelopmental expert assessed patients over a period of 12 months. Results. Twenty-five files out of a total of 100 were excluded owing to missing data. In accordance with the Thompson HIE score, the cohort was classified as mild (56%), moderate (27%), and severe (17%). All included patients (n=75) had full blood counts within 6 hours of delivery. nRBC were detected in 52% of the samples. There was no correlation between nRBC category and HIE severity (p=0.265). Raised nRBCs (≥30 cells/100 white blood cells (WBCs)) were more frequent in infants who died than in those who survived (p=0.008). Infants with nRBC counts ≥30 cells/100 WBCs had an increased likelihood of having cerebral palsy or impaired neurodevelopment (p=0.013). Conclusion. The study demonstrated a significant association between an early increase in nRBC counts in HIE infants treated with TH, and both short-and long-term outcomes. A larger multicentre study is required to better understand the relationship between nRBC counts and HIE in the era of cooling in our local setting.