Supplementary Material for: Optimizing Cerebral Autoregulation May Decrease Neonatal Regional Hypoxic-Ischemic Brain Injury

Background: Therapeutic hypothermia provides incomplete
neuroprotection for neonatal hypoxic-ischemic encephalopathy (HIE). We
examined whether hemodynamic goals that support autoregulation are
associated with decreased brain injury and whether these relationships
are affected by birth asphyxia or vary by anatomic region. Methods:
Neonates cooled for HIE received near-infrared spectroscopy
autoregulation monitoring to identify the mean arterial blood pressure
with optimized autoregulatory function (MAPOPT). Blood pressure deviation from MAPOPT
was correlated with brain injury on MRI after adjusting for the effects
of arterial carbon dioxide, vasopressors, seizures, and birth asphyxia
severity. Results: Blood pressure deviation from MAPOPT
related to neurologic injury in several regions independent of birth
asphyxia severity. Greater duration and deviation of blood pressure
below MAPOPT were associated with greater injury in the paracentral gyri and white matter. Blood pressure within MAPOPT
related to lesser injury in the white matter, putamen and globus
pallidus, and brain stem. Finally, blood pressures that exceeded MAPOPT were associated with reduced injury in the paracentral gyri. Conclusions:
Blood pressure deviation from optimal autoregulatory vasoreactivity was
associated with MRI markers of brain injury that, in many regions, were
independent of the initial birth asphyxia. Targeting hemodynamic ranges
to optimize autoregulation has potential as an adjunctive therapy to
hypothermia for HIE.