161 - Earlier initiation of therapeutic hypothermia at less than 3 hours of life does not improve the rate of brain injury on MRI or death in newborn infants with moderate to severe HIE.

Poster Number: 161
Publication Number: 161.136

PRIYA MISHRA, Sidney Kimmel Medical College at Thomas Jefferson University, Wilmington, DE, United States; Kiran S. Talekar, Sidney Kimmel Medical College at Thomas Jefferson University, Media, PA, United States; Oluwatobi Adegboyega, Sidney Kimmel Medical College at Thomas Jefferson University, Media, PA, United States; Dorothy L. McElwee, The Nemours Foundation, mullica hill, NJ, United States; David Carola, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, United States; Susan Adeniyi-Jones, Sidney Kimmel Medical College at Thomas Jefferson University, Wynnewood, PA, United States; Kolawole O. Solarin, NemoursAlfred I. duPont Hospital for Children/Thomas Jefferson University Hospital, Philadelphia, PA, United States; Kevin Dysart, Nemours Children's Health/Thomas Jefferson University, PHILADELPHIA, PA, United States; Zubair Aghai, Sidney Kimmel Medical College at Thomas Jefferson University, Philadelphia, PA, United States

Background: Hypoxic–ischemic encephalopathy (HIE) is an important cause of death and disability in late preterm and full-term infants. Therapeutic hypothermia (TH) is the standard of care for infants with moderate and severe HIE and when started within first 6 hours of life, it has been shown to improve survival and neurodevelopmental outcomes. However, it is unknown whether starting TH earlier than 3 hours of life has an added benefit and limited retrospective studies have had conflicting results.

Objective: To compare brain injury on MRI or death in infants with moderate or severe HIE when therapeutic hypothermia was initiated within first 3 hours of life (Early cooling group) vs. after 3 hours of life (Late cooling group). 

Design/Methods: This is a retrospective single center study of infants born at > 35 weeks of gestation, diagnosed with moderate or severe HIE (modified Sarnat stage 2 or 3) who underwent therapeutic hypothermia. Infants in Early cooling group were compared with infants in Late cooling group, logistic regression was performed to adjust for variables that were different in two groups. A neuro- radiologist blinded to clinical information scored severity of brain injury using the basal ganglia/watershed (BG/W) scoring system. Primary outcome was a composite of brain injury on MRI or death. Secondary outcomes were rate of severe brain injury on MRI or death.

Results:

325 infants met the inclusion criteria. Of those, 48 infants were included in the Early cooling group and 277 in the Late cooling group. Demographic and baseline characteristics were similar in two groups except in Late cooling group, more infants were out born and had higher base deficit.  Passive cooling was initiated in 216 (78%) infants in Late cooling group. The composite outcome of death or abnormal MRI finding was higher in Late cooling group compared to Early cooling group (44.3% vs 21.3%, P = 0.003). Late cooling group also had significantly higher rate of death or severe abnormalities on MRI (24.2% vs 4.3%, P = 0.001).  However, these differences were not significant when adjusted for the out born status and base deficit.

Conclusion(s):

Earlier initiation of therapeutic hypothermia in newborn infants with moderate or severe HIE was not associated with lower risk of death or findings of brain injury on MRI. We speculate that the small sample size in Early cooling group and passive cooling of infants in Late cooling group may have contributed to our findings.