Perinatal Events and Outcomes Associated with Hypoxic-Ischemic Encephalopathy in Thailand: A Multicenter, Observational Study

Background: Risk factors for perinatal hypoxic-ischemic encephalopathy (HIE) differ across high- and low- or middle-income countries. Recent evidence from a randomized trial of therapeutic hypothermia (TH) suggests that the intervention should not be offered in the aforementioned countries because of higher mortality rates and associated morbidity. Objective: To investigate characteristics of infants of 35 weeks or more gestational age (GA) born with HIE and determine the short-term outcomes of recipients of TH. Materials and Methods: A multicenter, retrospective, chart review was conducted of infants with 5-minute Apgar scores of 5 or less admitted to the four tertiary centers in Thailand between 2013 and 2020. Events associated with perinatal hypoxia and outcomes were extracted. Results: The incidence of perinatal HIE was 0.8 per 1,000 livebirths. Among 225 HIE infants, 46.2% had metabolic acidosis, 58.1% experienced hypoxic events, and 92.8% required advanced resuscitation. Among 123 infants who met TH criteria, 83 (67.5%) were treated. The overall HIErelated mortality rate was 24.9%. TH recipients had a lower mortality rate than untreated infants at 32.5% versus 52.5%, respectively (p=0.03) with a relative risk of 0.62 (95% CI 0.40 to 0.95). The findings were comparable to the reports from high-income countries. Conclusion: To correctly select neonates for TH, increased HIE awareness, mandatory cord blood gas analysis, and country-wide dissemination of eligible criteria are necessary for timely intervention. Keywords: Middle-income country; Encephalopathy; Risk factors; Hypoxic-ischemia; Therapeutic hypothermia