Variability of resistive indices in the anterior cerebral artery during fontanel compression in preterm and term neonates measured by transcranial duplex sonography

Objective:to determine the normal range of resistive index (ri) variability in clinically/neurologically unremarkable preterm and term infants and to compare the hemodynamic response to transient elevation of intracranial pressure.study design:we measured ris at baseline and following brief fontanel compression, assessing for differences in mean baseline and compression values and percent change.result:one hundred and twenty-nine subjects were included in the study. mean baseline ri and normal range were 0.7 in preterm (0.54 to 0.86) and 0.66 in term infants (0.52 to 0.8; p=0.001). mean ri during compression was 0.71 in preterm and 0.68 in term infants (p=0.015). mean percent change between baseline and compression was 5.86% in preterm and 7.45% in term infants (p=0.092).conclusion:no difference in the hemodynamic response to transient elevation of intracranial pressure between different gestational groups, suggesting no significant differences in autoregulatory response.