tailieunhanh - Báo cáo y học: " The velocity of the arterial pulse wave: a viscous-fluid shock wave in an elastic tube"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học quốc tế cung cấp cho các bạn kiến thức về ngành y đề tài: " The velocity of the arterial pulse wave: a viscous-fluid shock wave in an elastic tube | Theoretical Biology and Medical Modelling BioMed Central Open Access The velocity of the arterial pulse wave a viscous-fluid shock wave in an elastic tube Page R Painter Address Office of Environmental Health Hazard Assessment California Environmental Protection Agency P. O. Box 4010 Sacramento California 95812 USA Email Page R Painter - ppainter@ Published 29 July 2008 Received 11 April 2008 Theoretical Biology and Medical Modelling 2008 5 15 doi 1742-4682-5-15 Accepted 29 July 2008 This article is available from http content 5 1 15 2008 Painter licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License http licenses by which permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited. Abstract Background The arterial pulse is a viscous-fluid shock wave that is initiated by blood ejected from the heart. This wave travels away from the heart at a speed termed the pulse wave velocity PWV . The PWV increases during the course of a number of diseases and this increase is often attributed to arterial stiffness. As the pulse wave approaches a point in an artery the pressure rises as does the pressure gradient. This pressure gradient increases the rate of blood flow ahead of the wave. The rate of blood flow ahead of the wave decreases with distance because the pressure gradient also decreases with distance ahead of the wave. Consequently the amount of blood per unit length in a segment of an artery increases ahead of the wave and this increase stretches the wall of the artery. As a result the tension in the wall increases and this results in an increase in the pressure of blood in the artery. Methods An expression for the PWV is derived from an equation describing the flow-pressure coupling FPC for a pulse wave in an incompressible viscous fluid in an elastic tube. The initial increase .