Predictors of neurological outcome in cooled neonates

Abstract

We define clinical predictors of neurological outcome in neonates with hypoxic-ischemic encephalopathy undergoing hypothermia therapy. Twenty-one neonates who underwent selective head cooling between 2004 and 2010 and were followed neurologically for ≥ 24 months were investigated retrospectively. Patients were divided according to the neurological outcome at 2 years of age into group A (n = 11), patients with normal neurological function, and group B (n = 10), patients with neurological disabilities (n = 9) or those who died (n = 1). Predictors were determined by χ(2) and Mann-Whitney U-tests, anova, Spearman rank correlations and receiver-operator curves. Group B showed higher average blood lactate levels during the first day, particularly at 24 h of life; lower day-3 cerebral blood flow resistance index; higher maximum dobutamine dose used; higher rate of thiamylal sodium used; more severe background electroencephalogram suppression during the first week (group A: 11/11 cases ≤ grade 3; group B: 7/9 cases at grade 4-5) and higher rate of cerebral lesions on magnetic resonance imaging in the second week (group A: 1/11 case; group B: 9/10 cases) than group A. The most useful predictor of poor prognosis was cerebral parenchymal lesions on magnetic resonance imaging with 90%, 90% and 90% of sensitivity, specificity and accuracy, followed by week-1 background electroencephalogram ≥ grade 4 with 70%, 100% and 85% and day-3 cerebral blood flow resistance index < 0.46 with 71%, 88% and 80%, respectively. Prediction of post-cooling neurological outcome could be improved substantially by evaluating multiple factors.