A Retrospective Study of Therapeutic Hypothermia in Neonatal Hypoxic Ischemic Encephalopathy

Abstract

Objectives: Therapeutic hypothermia (TH) is now standard treatment for moderate to severe hypoxic ischemic encephalopathy (HIE), secondary to intrapartum hypoxia, and has been performed in our neonatal unit since 2008. Objectives of this study included the assessment of compliance with the TH protocol and the evaluation of 2-year outcomes. Materials and Methods: Medical records of all the infants who underwent TH (2008-2014) were reviewed and relevant data were extracted. The laboratory database was used to extract blood test results. Follow-up clinic records were reviewed to gather data for 2-year outcomes. Outcome at 2 years was dichotomized as normal (survival with no or mild impairment) and abnormal (death or survival with moderate or severe impairment). Regression analysis was performed to determine the association of perinatal variables with an abnormal outcome. Results: Seventy-seven infants were treated with TH with 40/77 (52%) cooled as per the protocol. Treatment with TH for stage 1 HIE was the most common reason for protocol noncompliance. A total of 71 infants had HIE (n = 26, 24, and 21 with modified Sarnat stages 1, 2, and 3 respectively). Sixteen infants with HIE (22.5%) died; all had stage 3 HIE. Forty-one infants were seen at ≥2 years. Of these, 34 infants (83%) had a normal outcome. The clinical stage of HIE was the strongest predictor of an abnormal outcome. Normal 2-year outcome was seen in 94%, 84%, and 5% of stages 1, 2, and 3 HIE respectively. Conclusions: We noted a high degree of variation from the TH protocol. Clinical staging of HIE remains the strongest predictor of long-term outcome.