The Utility of Cerebral Autoregulation Indices in Detecting Severe Brain Injury Varies by Cooling Treatment Phase in Neonates with Hypoxic-Ischemic Encephalopathy

May W. Chen, Jennifer K. Lee, Gilbert Vezina, Aylin Tekes, Jamie Perin, Ruoying Li, Alexandra O'Kane, Meaghan McGowan, Taeun Chang, Charlamaine Parkinson, Colleen Krein, Tareq Al-Shargabi, Frances J. Northington, Ken M. Brady, An N. Massaro, Rathinaswamy B. Govindan

Research output: Contribution to journalArticlepeer-review

Abstract

Identifying the hemodynamic range that best supports cerebral perfusion using near infrared spectroscopy (NIRS) autoregulation monitoring is a potential physiologic marker for neonatal hypoxic-ischemic encephalopathy (HIE) during therapeutic hypothermia. However, an optimal autoregulation monitoring algorithm has not been identified for neonatal clinical medicine. We tested whether the hemoglobin volume phase (HVP), hemoglobin volume (HVx), and pressure passivity index (PPI) identify changes in autoregulation that are associated with brain injury on MRI or death. The HVP measures the phase difference between a NIRS metric of cerebral blood volume, the total hemoglobin (THb), and mean arterial blood pressure (MAP) at the frequency of maximum coherence. The HVx is the correlation coefficient between MAP and THb. The PPI is the percentage of coherent MAP-DHb (difference between oxygenated and deoxygenated hemoglobin, a marker of cerebral blood flow) epochs in a chosen time period. Neonates cooled for HIE were prospectively enrolled in an observational study in two neonatal intensive care units. In analyses adjusted for study site and encephalopathy level, all indices detected relationships between poor autoregulation in the first 6 h after rewarming with a higher injury score on MRI. Only HVx and PPI during hypothermia and the PPI during rewarming identified autoregulatory dysfunction associated with a poor outcome independent of study site and encephalopathy level. Our findings suggest that the accuracy of mathematical autoregulation algorithms in detecting the risk of brain injury or death may depend on temperature and postnatal age. Extending autoregulation monitoring beyond the standard 72 h of therapeutic hypothermia may serve as a method to provide personalized care by assessing the need for and efficacy of future therapies after the hypothermia treatment phase.

Original languageEnglish (US)
Pages (from-to)363-372
Number of pages10
JournalDevelopmental Neuroscience
Volume44
Issue number4-5
DOIs
StatePublished - Sep 1 2022

Keywords

  • Brain injury
  • Cerebral autoregulation
  • Hypothermia
  • MRI
  • Near infrared spectroscopy
  • Neonatal hypoxia-ischemia

ASJC Scopus subject areas

  • Neurology
  • Developmental Neuroscience

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