Tyberg John V, Davies Justin E, Wang Zhibin, Whitelaw William A, Flewitt Jacqueline A, Shrive Nigel G, Francis Darryl P, Hughes Alun D, Parker Kim H, Wang Jiun-Jr
Department of Cardiac Sciences, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada.
Med Biol Eng Comput. 2009 Feb;47(2):221-32. doi: 10.1007/s11517-008-0430-z. Epub 2009 Feb 3.
The parameters of wave intensity analysis are calculated from incremental changes in pressure and velocity. While it is clear that forward- and backward-traveling waves induce incremental changes in pressure, not all incremental changes in pressure are due to waves; changes in pressure may also be due to changes in the volume of a compliant structure. When the left ventricular ejects blood rapidly into the aorta, aortic pressure increases, in part, because of the increase in aortic volume: aortic inflow is momentarily greater than aortic outflow. Therefore, to properly quantify the effects of forward or backward waves on arterial pressure and velocity (flow), the component of the incremental change in arterial pressure that is due only to this increase in arterial volume--and not, fundamentally, due to waves--first must be excluded. This component is the pressure generated by the filling and emptying of the reservoir, Otto Frank's Windkessel.
波强度分析的参数是根据压力和速度的增量变化计算得出的。虽然很明显向前和向后传播的波会引起压力的增量变化，但并非所有压力的增量变化都是由波引起的；压力变化也可能是由于顺应性结构体积的变化。当左心室迅速将血液射入主动脉时，主动脉压力会升高，部分原因是主动脉容积增加：主动脉流入量暂时大于主动脉流出量。因此，为了正确量化向前或向后波对动脉压力和速度（流量）的影响，首先必须排除仅由动脉容积增加引起的动脉压力增量变化部分，而从根本上来说，这部分变化并非由波引起。这部分压力是由贮液器（奥托·弗兰克的风箱）的充盈和排空产生的。
