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Updated: Dec 6, 2025

Evaluation of Cerebral Blood Flow Autoregulation in the Rat Using Laser Doppler Flowmetry
Published on: January 19, 2020
The association between carbon dioxide, cerebral blood flow, and autoregulation in the premature infant
Suma Bhat Hoffman1, Anisa Lakhani2, Rose Marie Viscardi2
1Department of Pediatrics, University of Maryland Baltimore, School of Medicine, Baltimore, MD, USA. sbhoffman@childrensnational.org.
Objective:
Evaluate the association between carbon dioxide (pCO2), cerebral blood flow (CBF), and cerebral autoregulation (CA) in preterm infants.
Study Design:
Cerebral saturations (rScO2, surrogate for CBF using NIRS) and mean arterial blood pressure (MAP) monitored for 96 h in infants <29 weeks gestation. Relationship between rScO2, the rScO2-MAP correlation (CA analysis) and pCO2 category assessed by mixed effects modeling.
Results:
Median pCO2 differed by postnatal day (p < 0.0001)-pCO2 increased between day 1 and 2, and low variability seen on day 4. A 5% increase in rScO2 was noted when pCO2 was >55 mmHg on each postnatal day (p < 0.001). No association observed between the overall rScO2-MAP correlation and pCO2. On day 1 only, the correlation coefficient decreased from 0.26 to -0.09 as pCO2 category increased (p = 0.02).
Conclusions:
CBF increased above a pCO2 threshold of 55 mmHg, but overall, no association between pCO2 and CA was noted.
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