Key result
In healthy full-term neonates, the flow velocity of the middle cerebral artery increased during the first three days after birth while its resistance index remained constant, whereas the common carotid artery flow velocity did not change.
Observational (n=20)
No
Simultaneous Doppler measurements in healthy neonates show increasing middle cerebral artery flow velocity with constant resistance indices over the first three days of life, suggesting cerebral arteries may act as resistance vessels independent of systemic circulation changes.
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Neonatal cerebral flow rises independently of carotid changes; hypothesis-generating for Doppler monitoring in at-risk infants.
We measured simultaneously the flow velocity curves of the common carotid artery and the middle cerebral artery to evaluate the relationship between the systemic and cerebral circulations in the early neonatal period. Eligible for inclusion in this study were 20 healthy full-term neonates. Doppler ultrasound examinations were performed at 1, 2, 3, and 4 days after birth. The flow velocity curves of both arteries were recorded using a multi-channel Doppler system. Systolic maximal velocities and end-diastolic velocities were measured, and resistance indices (RIs) were calculated. The flow velocity of the middle cerebral artery increased during the first three days after birth, but that of the common carotid artery did not change. The RI of the middle cerebral artery remained constant, but that of the common carotid artery decreased on the third day after birth. These data suggest that the cerebral arteries might work as resistance vessels.
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Ichihashi et al. (1998) conducted an observational in Healthy full-term neonates (n=20). Postnatal age (days 1 to 4) vs. Baseline (day 1) was evaluated on Changes in systolic maximal velocity, end-diastolic velocity, and resistance index in the middle cerebral and common carotid arteries. In healthy full-term neonates, the flow velocity of the middle cerebral artery increased during the first three days after birth while its resistance index remained constant, whereas the common carotid artery flow velocity did not change.
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