Abnormal Amplitude-Integrated Electroencephalography and Acidosis as Key Criteria Initiating Therapeutic Hypothermia in Asphyxiated Newborns - Data From the German Hypothermia Registry.

AIM: There is a wide treatment heterogeneity for asphyxiated newborn infants between hospitals in Germany. This study aimed to identify the leading entry criteria initiating therapeutic hypothermia (TH) using data from the German Hypothermia Registry. METHODS: We retrospectively analyzed 262 asphyxiated newborn infants treated with TH across 74 neonatal units in Germany. Clinical and metabolic parameters and neurological assessments were recorded before the initiation of TH using a standardised electronic form in REDCap, a secure web-based platform for clinical research. Correlations between metabolic indicators (pH, base deficit, lactate) and neurological assessments, including Sarnat score, Thompson score and initial amplitude-integrated electroencephalography (aEEG) were examined. RESULTS: Mean gestational age was 39.4 ± 1.7 weeks. Acidosis and abnormal aEEG patterns were the most frequent criteria initiating treatment. Lower pH was strongly associated with abnormal aEEG (odds ratio 0.02, 95% confidence interval 0.002-0.19, p < 0.01). Base deficit and lactate showed weaker, non-significant associations. Lower 10-min Apgar scores predicted abnormal aEEG (odds ratio 0.77, 95% confidence interval 0.69-0.87, p < 0.001). CONCLUSION: Severe acidosis (pH < 7.0) was significantly associated with abnormal aEEG patterns, the main determinant initiating TH. Identifying abnormal aEEG patterns is essential for confirming moderate to severe encephalopathy and guiding treatment.