Background and objective Infants with hypoxic-ischemic encephalopathy (HIE) are treated with therapeutic hypothermia (HT). Following perinatal asphyxia amplitude-integrated EEG (aEEG) and near-infrared spectroscopy (NIRS) are used to determine prognosis. We aimed to assess the prognostic value of aEEG and NIRS during HT.
Methods 40 term infants with HIE and treatment with HT were retrospectively studied. aEEG and NIRS were started immediately following admission. aEEGs were assessed by pattern recognition: background pattern (BP), presence of sleep wake cycling (SWC) and epileptic activity (EA) were appraised. Recordings during HT (72 hrs) were analysed.
Results 84% of infants had an abnormal BP (discontinuous normal voltage, burst suppression (BS), continuous low voltage (CLV) or flat trace (FT)) at admission. The LR+ (95% CI) of an severely abnormal BP (BS, CLV, FT) for mortality was 1.97 (1.24–3.12) at 6h after birth and increased to 4.5 (3.16–6.39) at 24h, 6.3 (2.04–19.4) at 48h and 6.19 (1.93–19.8) at 72h. LR+ of BS for mortality was below 1 at any time. LR+ of EA for mortality was 4.95 (2.20–11.1), the type of EA (e.g. status epilepticus) was not predictive. LR+ of SWC for survival was 10.7 (1.62–70). RcSO2 increased from 6 to 72h after birth, but was not different at any time between infants that died or survived.
Conclusion aEEG during HT can still be used to predict risk for mortality of HIE, especially beyond 24 hrs. BS is frequently not associated with a fatal outcome. RcSO2 has no additional value to predict mortality.