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Updated: Dec 26, 2025
Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry
Published on: January 19, 2020
Cerebral venous volume changes and pressure autoregulation in critically ill infants
Vedavalli Govindan1, Rathinaswamy Govindan1, An N Massaro1,2
1Divisions of Fetal and Transitional Medicine, Children's National Hospital, Washington, DC, USA.
Objective:
To determine whether ventilator-related fluctuations in cerebral blood volume (CBV) are associated with cerebral pressure passivity.
Study Design:
In a prospective study of newborns undergoing positive-pressure ventilation, we calculated coherence between continuous mean arterial pressure (MAP) and cerebral near-infrared spectroscopy hemoglobin difference (HbD). Significant HbD-MAP coherence indicated cerebral pressure passivity. CBV changes were measured as the spectral power of total hemoglobin (SHbT) at the ventilator frequency. A regression model tested whether SHbT predicts cerebral pressure passivity and/or death/brain injury, controlling for birth gestational age and other factors.
Results:
We studied 68 subjects with prematurity (n = 19), congenital heart disease (n = 11), and hypoxic-ischemic encephalopathy (n = 38). SHbT, sedative use, and pCO2 were positively associated, and circulating hemoglobin negatively associated, with cerebral pressure passivity (p < 0.001), which was positively associated with brain injury (p < 0.001).
Conclusion:
In sick newborns, ventilator-related CBV fluctuations may predispose to cerebral pressure passivity, which may predispose to an adverse neonatal outcome.
