Vasoparalysis associated with brain damage in asphyxiated term infants

Area of Science:

• Neonatal Neurology
• Cerebrovascular Physiology
• Pediatric Critical Care

Background:

• Perinatal asphyxia poses a significant risk for neonatal brain injury.
• Understanding cerebral blood flow (CBF) regulation is crucial for managing asphyxiated infants.
• Cerebral autoregulation, the ability to maintain stable CBF despite blood pressure changes, is vital.

Purpose of the Study:

• To investigate the relationship between cerebral blood flow and arterial carbon dioxide/mean arterial blood pressure in asphyxiated term infants.
• To assess the reactivity of CBF to changes in carbon dioxide and mean arterial blood pressure.
• To correlate CBF dynamics and electrophysiological findings with neurological outcomes.

Main Methods:

• Global cerebral blood flow (CBF) was measured using Xenon-133 clearance in 19 asphyxiated and 12 control infants.
• Amplitude-integrated electroencephalogram (aEEG) and visual-evoked potentials (VEPs) were recorded concurrently.
• Cerebral blood flow reactivity to arterial carbon dioxide and mean arterial blood pressure (MABP) was analyzed.

Main Results:

• Asphyxiated infants with isoelectric EEG and high CBF (30.6 ml/100 gm/min) had abolished CO2 and MABP reactivity, and died with severe brain damage.
• Infants with burst-suppression EEG and lower CBF (14.7 ml/100 gm/min) showed abolished MABP reactivity but preserved CO2 reactivity; they developed brain lesions.
• Asphyxiated infants without neurological abnormalities and controls demonstrated preserved CO2 and MABP reactivity.

Conclusions:

• Abolished cerebral autoregulation is strongly associated with cerebral damage in perinatal asphyxia.
• The combination of isoelectric EEG and cerebral hyperperfusion serves as an early indicator of extremely severe brain injury.
• Preserved CBF reactivity to CO2 and MABP suggests intact autoregulation and is associated with better outcomes.