Middle cerebral artery blood flow velocity in the newborn following delivery.
Ninety-five normally grown term and preterm newborns were examined to determine the means and prediction limits of cerebral blood flow velocity following delivery and to examine the relationship of systemic blood pressure to cerebral blood flow velocity. Doppler blood flow velocity was observed during the four days following delivery. Continuous measures of blood pressure and heart rate were recorded concurrently. Mean peak systolic and end diastolic blood flow velocity immediately following delivery was 43.2 and 9.3 cm/sec for term newborn, and 31.8 and 3.3 cm/sec for preterm newborn. During the 24 h following delivery there was no change of peak systolic blood flow velocity but a two to three fold increase of end diastolic blood flow velocity in the term and preterm newborn. The reference limits for peak systolic and end diastolic blood flow velocity provide criteria to define abnormal increases and decreases of blood flow velocity. During the 24 h following delivery, increasing diastolic blood pressure was associated with increasing end diastolic blood flow velocity independent of birth weight and time following delivery. Also there was a significant correlation between systemic pressure pulsatile index and middle cerebral artery blood flow velocity pulsatile index. Thus systemic blood pressure pulsatility must be recognized as distinct from other intracerebral influences on cerebral blood flow velocity regulation in the newborn.
Low
J A
JA
Department of Obstetrics and Gynaecology, Queen's University, Kingston, Ontario.
Froese
A B
AB
Galbraith
R S
RS
Smith
J T
JT
Karchmar
E J
EJ
D001783:Blood Flow Velocity; D001794:Blood Pressure; D002536:Cerebral Arteries / Q000502:physiology*; D003971:Diastole; D006801:Humans; D007231:Infant, Newborn / Q000502:physiology*; D007234:Infant, Premature / Q000502:physiology; D013599:Systole; D013997:Time Factors