Therapeutic hypothermia in mild hypoxic ischemic encephalopathy: A clinical dilemma with uncertain long-term outcomes

Abstract

Objective

To evaluate short-term and neurodevelopmental outcomes at 18–24 months in infants with mild hypoxic-ischemic encephalopathy (HIE) treated with therapeutic hypothermia (TH), a population with limited long-term outcome data.

Study design

We conducted a retrospective cohort study of neonates ≥36 weeks gestational age (GA) diagnosed with mild HIE and treated with TH at a single center from March 2017 to February 2022. Neonates with severe congenital malformations or chromosomal anomalies were excluded. Data were extracted from medical charts of eligible neonates and their mothers. Outcomes assessed included short-term measures (neuroimaging findings, seizure incidence, length of hospital stay (LOS), and background electroencephalogram (EEG) abnormalities) and long-term neurodevelopmental outcomes (Bayley Scales of Infant and Toddler Development) at 18–24 months or pediatrician-documented developmental delays.

Results

Of the 64 infants meeting inclusion criteria, 17 (27 %) had MRI findings consistent with HIE, and 8 (13 %) experienced seizures. Long-term outcome data were available for 57 (89 %); of whom 9 (16 %) had abnormal outcomes. Among the 39 infants who underwent Bayley assessment at 22 ± 2 months, 6 (15 %) scored <85 in language, cognitive, or motor domains. Of the 17 infants without Bayley assessment but with pediatrician follow-up, 3 (18 %) had documented developmental delays.

Conclusion

Although TH is increasingly applied to mild HIE, evidence on long-term benefit remains scarce. In our cohort, infants with mild HIE treated with TH exhibited seizures, MRI abnormalities, and developmental impairments, underscoring the persistent risk of morbidity. These findings highlight the limited outcome data available and the urgent need for well designed prospective studies to clarify the role of TH in mild HIE.