Wave detection in acceleration plethysmogram.
Wave detection in acceleration plethysmogram.
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DOI：
10.4258/hir.2015.21.2.111
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发表时间：
2015-04
影响因子：
2.9
通讯作者：
Ahn JM
中科院分区：
文献类型：
--
作者：
Ahn JM
利用光体积描记(PPG)的二阶导数得到的加速体积图(APG)预测动脉粥样硬化的危险因素。这项技术有望用于动脉粥样硬化病理的早期筛查。然而，从指尖测量的APG信号的波指数的提取是具有挑战性的。本文提出了一种基于微控制器的前置放大器的波形检测算法，该算法可以检测a、b、c和d波指数。为了更好地分离波形成分，提高波形检测的成功率，引入了脉搏波在实际测量下的四阶导数。设计了一种带有Sallen-key低通滤波器的前置放大器和具有可编程增益控制、数学微分和数字IIR陷波滤波器的波形检测算法。评估了数字IIR滤波器的频率响应，并产生了由存在波折射率的特定区域组成的脉冲序列。可编程增益控制在不同的PPG幅度下，在输出端保持恒定的APG幅度。164例受试者APG信号大小对应的a波指数平均值和标准差分别为1106.45和±47.75。我们的结论是，所提出的算法和前置放大器设计用于实时提取APG的波形指数，对于评估简单医疗设备中心血管系统的血管老化是有用的。
Acceleration plethysmogram (APG) obtained from the second derivative of photoplethysmography (PPG) is used to predict risk factors for atherosclerosis with age. This technique is promising for early screening of atherosclerotic pathologies. However, extraction of the wave indices of APG signals measured from the fingertip is challenging. In this paper, the development of a wave detection algorithm including a preamplifier based on a microcontroller that can detect the a, b, c, and d wave indices is proposed. The 4th order derivative of a PPG under real measurements of an APG waveform was introduced to clearly separate the components of the waveform, and to improve the rate of successful wave detection. A preamplifier with a Sallen-Key low pass filter and a wave detection algorithm with programmable gain control, mathematical differentials, and a digital IIR notch filter were designed. The frequency response of the digital IIR filter was evaluated, and a pulse train consisting of a specific area in which the wave indices existed was generated. The programmable gain control maintained a constant APG amplitude at the output for varying PPG amplitudes. For 164 subjects, the mean values and standard deviation of the a wave index corresponding to the magnitude of the APG signal were 1,106.45 and ±47.75, respectively. We conclude that the proposed algorithm and preamplifier designed to extract the wave indices of an APG in real-time are useful for evaluating vascular aging in the cardiovascular system in a simple healthcare device.