Zahedi Edmond, Chellappan Kalaivani, Ali Mohd Alauddin Mohd, Singh Harwant
School of Engineering, SHARIF University of Technology, Tehran, Iran.
Cardiovasc Eng. 2007 Dec;7(4):172-81. doi: 10.1007/s10558-007-9037-5.
Ageing is one of the main contributing factors towards increasing arterial stiffness, leading to changes in peripheral pulses propagation. Therefore the characteristics of the photoplethysmogram (PPG) pulse, especially the rising edge and peak position, are greatly affected. In this study, the PPG pulse rising edge and corresponding peak position have been investigated non-invasively in human subjects as a function of age. Fifteen healthy subjects were selected and grouped in five age intervals, from 20 to 59 years, based on their comparable systolic-diastolic blood pressure and PPG amplitude. As expected, the peripheral pulse shows a steep rise and early peak in younger subjects. With age, the slope becomes blunted and in older subjects, the rise is very gradual and the pulse peak appears much later. Qualitative results were further verified by a modified 10-element Windkessel model to quantify the lumped parameter changes with ageing. This verification highlighted some specific changes in vascular parameters with aging. The rising edge could be considered as one parameter in determining the age-dependent vascular state.
衰老为动脉僵硬度增加的主要促成因素之一，会导致外周脉搏传播发生变化。因此，光电容积脉搏波（PPG）的脉冲特征，尤其是上升沿和峰值位置，会受到极大影响。在本研究中，已在人类受试者中对PPG脉冲上升沿及相应峰值位置随年龄的变化进行了无创研究。选取了15名健康受试者，并根据其可比的收缩压-舒张压及PPG幅度，将他们分为五个年龄区间，年龄范围为20至59岁。正如预期的那样，年轻受试者的外周脉搏上升陡峭且峰值出现较早。随着年龄增长，斜率变得平缓，在老年受试者中，上升非常缓慢且脉冲峰值出现得更晚。通过一个经过修改的十元件Windkessel模型对定性结果进行了进一步验证，以量化随衰老的集总参数变化。这一验证突出了血管参数随衰老的一些特定变化。上升沿可被视为确定年龄依赖性血管状态的一个参数。
