657 - Outcomes of Infants with Postnatal Hypoxic-Ischemic Encephalopathy: Does Therapeutic Hypothermia work?

Publication Number: 657.5713

Rakesh Rao, Washington University in St. Louis School of Medicine, St. Louis, MO, United States; Isabella Zaniletti, IZ Statistic LLC, Tampa, FL, United States; Jeffrey Shenberger, Connecticut Children's Medical Center, Hartford, CT, United States; Maria Dizon, Northwestern University, CHICAGO, IL, United States; Elizabeth K. Sewell, Emory University School of Medicine; Children's Healthcare of Atlanta, Atlanta, GA, United States; Mehmet N.. Cizmeci, The Hospital for Sick Children, Toronto, ON, Canada; Ulrike Mietzsch, University of Washington School of Medicine, Seattle, WA, United States; Ryan M. McAdams, University of Wisconsin, Middleton, WI, United States; Karna Murthy, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, United States; Robert DiGeronimo, Seattle Children's, Seattle, WA, United States; Theresa Grover, University of Colorado School of Medicine, Aurora, CO, United States; Michael A. Padula, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States; Girija Natarajan, Central Michigan University College of Medicine, Detroit, MI, United States

Background: Therapeutic hypothermia (TH) for newborn infants with moderate-severe hypoxic-ischemic encephalopathy (HIE) identified in the perinatal period is associated with improved survival without increasing neurodevelopmental impairment. TH initiated in infants and children following hypoxic or cardiac arrest has shown minimal benefit. The benefit of TH for neonates with HIE diagnosed outside the immediate perinatal period remains unclear.

Objective: To evaluate the characteristics and outcomes of infants with postnatal HIE (non-perinatal or post arrest) treated with or without TH.

Design/Methods: The Children’s Hospitals Neonatal Consortium (CHNC) database was queried to identify infants ≥35 weeks gestation with postnatal HIE and admitted within 29 days of birth. Infants were stratified based on whether they received TH. The primary outcome measured was survival to discharge home without feeding support (nasogastric tube or gastrostomy tube). Data were analyzed using Chi-square and Wilcoxon rank-sum tests. Multivariable generalized linear mixed models were adjusted for primary admission reason, region, and center as a random effect.

Results: A total of 251 infants were identified with postnatal HIE of whom 108 (43%) received TH while the remaining 143 (57%) did not.
For the cohort (Table 1), the majority (85%) were referred from other hospitals, predominantly the neonatal intensive care unit. About 31% infants received resuscitation efforts outside the delivery room. Median [IQR} age at admission was 3 [1,6] days and the predominant reason for admission was neurological concern (23%). Seizures were identified in 7/251 (2.8%). Brain MRI was abnormal in 69/79 (87.5%) available studies.
Table 1 shows the clinical and demographic data for the two groups. The median [IQR] gestational age, birth weight, sex or race did not differ between groups. There were no differences in birth and delivery characteristics. TH was offered more frequently in the West and less frequently in the South (p = 0.001).
Among infants who received TH, cooling was initiated at median [IQR] age of 35.7 [8.3, 163.3] hours and continued for 72 [37, 72] hours duration.
In unadjusted analyses, TH was not associated with survival to discharge home without feeding support, in-hospital mortality, seizures or discharge home on anti-seizure medication, however, the length of stay (LOS) was shorter (Table 2). In adjusted analyses, TH was not associated with a shorter LOS (Table 2).

Conclusion(s): TH in infants with postnatal HIE showed no significant benefit with regards to survival to discharge without feeding support, mortality, LOS or seizures.

Table 1
Table 1Final.pdfClinical and demographic characteristics

Table 2
Table 2final.pdfUnadjusted and adjusted analyses.