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Interpretation of pulsatility index in feeder arteries to low‐impedance vascular beds
Author(s) -
Gosling R. G.,
Lo P. T. S.,
Taylor M. G.
Publication year - 1991
Publication title -
ultrasound in obstetrics and gynecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.202
H-Index - 141
eISSN - 1469-0705
pISSN - 0960-7692
DOI - 10.1046/j.1469-0705.1991.01030175.x
Subject(s) - medicine , pulsatility index , pulsatile flow , input impedance , resistive touchscreen , blood flow , flow (mathematics) , vascular resistance , cardiology , electrical impedance , blood pressure , mechanics , physics , electrical engineering , pregnancy , fetus , genetics , quantum mechanics , biology , engineering
A simple electrical circuit is proposed as a model for peripheral vascular beds of low impedance. The model consists of a flow and pressure source, i.e. the ‘feeder’ artery, with the vascular bed represented by a Zener diode Z giving rise to a ‘back pressure’ P z and a pure resistance R . By applying Ohm's law to the definition of pulsatility index PI flow of flow in the feeder artery, it is shown that PI flow is dependent only on the mean blood pressure (input), the pulse pressure and P z , and is independent of R . For those vascular beds where the impedance is largely resistive, e.g. the brain, the kidney and the uterine‐placental complex, it is suggested that P z may be a more useful characterizing parameter than the value of PI flow as at present used by some workers. Copyright © 1991 International Society of Ultrasound in Obstetrics and Gynecology