Title
Variation Of Wave Speed Determined By The Pu-Loop With Proximity To A Reflection Site
Abstract
Wave speed is directly related to arterial distensibility and is widely used by clinicians to assess arterial stiffness.The PU-loop method for determining wave speed is based on the water hammer equation for flow in flexible tubes and artery using the method of characteristics. This technique determines wave speed using simultaneous measurements of pressure and velocity at a single point. The method shows that during the early part of systole, the relationship between pressure and velocity is generally linear, and the initial slope of the PU-loop is proportional to wave speed.In this work, we designed an in-vitro experiment to investigate the effect of proximity to a reflection site on the wave speed determined by the PU-loop through varying the distance between the measurement and reflection sites. Measurements were made in a flexible tube with a reflection site at the distal end formed by joining the tube to another tube with a different diameter and material properties. Six different flexible tubes were used to generate both positive and negative reflection coefficients of different magnitudes.We found that the wave speed determined by the PU-loop did not change when the measurement site was far from the reflection site but did change as the distance to the reflection site decreased. The calculated wave speed increased with positive reflections and decreased with negative reflections. The magnitude of the change in wave speed at a fixed distance from the reflection site increased with increasing the value of the reflection coefficient.
Year
DOI
Venue
2011
10.1109/IEMBS.2011.6090032
2011 ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY (EMBC)
Keywords
Field
DocType
reflection coefficient,reflection,pressure measurement,method of characteristics,material properties,fluid flow,arterial pressure
Magnitude (mathematics),Wave shoaling,Computer science,Flow (psychology),Pressure measurement,Method of characteristics,Electronic engineering,Water hammer,Reflection coefficient,Material properties
Conference
Volume
ISSN
Citations 
2011
1557-170X
0
PageRank 
References 
Authors
0.34
1
4
Name
Order
Citations
PageRank
Ye Li100.68
Alessandra Borlotti201.35
Kim H Parker300.34
Ashraf Khir402.37