Transfontanellar Duplex Brain Ultrasonography Resistive Indices as a Prognostic Tool in Neonatal Hypoxic-Ischemic Encephalopathy Before and After Treatment with Therapeutic Hypothermia

OBJECTIVE: Prior to therapeutic hypothermia (i.e., cooling), transfontanellar duplex brain sonography resistive indices (RI) were studied as bedside non-invasive measures of cerebral hemodynamics in neonates who suffered from hypoxic-ischemic encephalopathy (HIE). We compared pre- and post-cooling RI values and examined the relationships between RI values and specific long-term neurodevelopmental outcomes. STUDY DESIGN: Transfontanellar duplex brain sonography, including RI, were obtained for 28 neonates prior to brain cooling and for 20 neonates following brain cooling. All RI values were sampled in the anterior cerebral artery at the beginning of each ultrasound study. Neurodevelopmental assessment was conducted between ages 20-32 months with the Mullen Scale of Early Learning. The relationships between pre- and post-cooling RI and cognitive and motor outcomes were studied. RESULT: Neonates with RI values <0.60 prior to and following cooling were more likely to die or have severe neurodevelopmental disability by ages 20-32 months than those with RI >0.60. Lower RI values were associated with specific neurodevelopmental deficits in motor skill attainment. CONCLUSION: Pre- and post-cooling transfontanellar duplex brain sonography RI values may be a useful prognostic tool, in conjunction with other clinical information, for neonates diagnosed with HIE. The results of this study suggest that further study of the prognostic value of RI values for short- and long-term outcomes is warranted.