title: A model of the instantaneous pressure-velocity relationships of the neonatal cerebral circulation.
abstract: The instantaneous relationship between arterial blood pressure (BP) and cerebral blood flow velocity (CBFV), measured with Doppler ultrasound in the anterior cerebral artery, is represented by a vascular waterfall model comprising vascular resistance, compliance, and critical closing pressure. One min recordings obtained from 61 low birth weight newborns were fitted to the model using a least-squares procedures with correction for the time delay between the BP and CBFV signals. A sensitivity analysis was performed to study the effects of low-pass filtering (LPF), cutoff frequency, and noise on the estimated parameters of the model. Results indicate excellent fitting of the model (F-test, p < 0.0001) when the BP and CBFV signals are LPF at 7.5 Hz. Reconstructed CBFV waveforms using the BP signal and the model parameters have a mean correlation coefficient of 0.94 with the measured flow velocity tracing (N = 232 epochs). The model developed can be useful for interpreting clinical findings and as a framework for research into cerebral autoregulation.
authors.affiliation: Division of Medical Physics, Faculty of Medicine, University of Leicester, UK.
authors.forename: R B
authors.initials: RB
authors.lastname: Panerai
authors.forename: H
authors.initials: H
authors.lastname: Coughtrey
authors.forename: J M
authors.initials: JM
authors.lastname: Rennie
authors.forename: D H
authors.initials: DH
authors.lastname: Evans
mesh_terms: D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002560:Cerebrovascular Circulation / Q000502:physiology*; D006801:Humans; D007230:Infant, Low Birth Weight / Q000502:physiology*; D007231:Infant, Newborn; D008954:Models, Biological; D013997:Time Factors