Cerebral blood flow fluctuation in low-risk preterm newborns.
Cerebral blood flow (CBF) fluctuation was studied by analyzing Doppler internal carotid blood velocity recordings of 13 healthy preterm newborns obtained in the course of their first 5 days of life. As measures of fluctuation we used the interquartile range (IQR) and the coefficient of variation (CV) of the ensemble of heart beats of a 20-s recording. In this way we determined fluctuation of the following velocity curve parameters (VCPs): end diastolic velocity; mean velocity; peak systolic velocity and pulsatility index (PI). The pooled data 5-95% intervals for fluctuation thus measured, were: 93-281% for CV; 0.6-3.7 cm/s for the IQR of the velocities; and 4-19% for the PI-IQR. Multiple regression analysis of IQR revealed significant relationships with: the VCP level; with restlessness; and with patency of the ductus arteriosus. Our findings imply that: (1) CBF has various qualities with different stability, mean velocity being the most stable; (2) for all the VCPs investigated, fluctuation is physiological in the early days after preterm birth; (3) most likely, there exists no age trend; (4) restlessness rather than wakefulness, enhances fluctuation; (5) patent ductus arteriosus destabilizes CBF; and (6) for a proper insight into fluctuation, the level of the VCP in question must be taken into account. We suggest that, the enhancing effect that patent ductus arteriosus has on fluctuation pays a contribution to the pathogenesis of brain damage. Finally, we conclude that the IQR represents fluctuation better than does the more commonly used CV.
Mullaart
R A
RA
Department of Child Neurology, University Hospital of Nijmegen, Netherlands.
Hopman
J C
JC
De Haan
A F
AF
Rotteveel
J J
JJ
Daniëls
O
O
Stoelinga
G A
GA
D001783:Blood Flow Velocity; D001784:Blood Gas Analysis; D002560:Cerebrovascular Circulation / Q000502:physiology*; D004374:Ductus Arteriosus, Patent / Q000503:physiopathology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D019271:Hypoxanthine; D007042:Hypoxanthines / Q000097:blood; D007231:Infant, Newborn; D007234:Infant, Premature / Q000254:growth & development / Q000502:physiology*; D012212:Rheology / Q000379:methods; D012307:Risk Factors
D007042:Hypoxanthines; D019271:Hypoxanthine