Gao Mingwu, Cheng Hao-Min, Sung Shih-Hsien, Chen Chen-Huan, Olivier Nicholas Bari, Mukkamala Ramakrishna
IEEE Trans Biomed Eng. 2017 Jul;64(7):1524-1534. doi: 10.1109/TBME.2016.2612639. Epub 2016 Sep 22.
pulse transit time (PTT) varies with blood pressure (BP) throughout the cardiac cycle, yet, because of wave reflection, only one PTT value at the diastolic BP level is conventionally estimated from proximal and distal BP waveforms. The objective was to establish a technique to estimate multiple PTT values at different BP levels in the cardiac cycle.
a technique was developed for estimating PTT as a function of BP (to indicate the PTT value for every BP level) from proximal and distal BP waveforms. First, a mathematical transformation from one waveform to the other is defined in terms of the parameters of a nonlinear arterial tube-load model accounting for BP-dependent arterial compliance and wave reflection. Then, the parameters are estimated by optimally fitting the waveforms to each other via the model-based transformation. Finally, PTT as a function of BP is specified by the parameters. The technique was assessed in animals and patients in several ways including the ability of its estimated PTT-BP function to serve as a subject-specific curve for calibrating PTT to BP.
the calibration curve derived by the technique during a baseline period yielded bias and precision errors in mean BP of 5.1 ± 0.9 and 6.6 ± 1.0 mmHg, respectively, during hemodynamic interventions that varied mean BP widely.
the new technique may permit, for the first time, estimation of PTT values throughout the cardiac cycle from proximal and distal waveforms.
the technique could potentially be applied to improve arterial stiffness monitoring and help realize cuff-less BP monitoring.
在整个心动周期中，脉搏传播时间（PTT）随血压（BP）变化，然而，由于波反射，传统上仅根据近端和远端血压波形估计舒张压水平下的一个PTT值。目的是建立一种技术，以估计心动周期中不同血压水平下的多个PTT值。
开发了一种从近端和远端血压波形估计PTT作为血压函数（以指示每个血压水平的PTT值）的技术。首先，根据考虑血压依赖性动脉顺应性和波反射的非线性动脉管负载模型的参数，定义从一个波形到另一个波形的数学变换。然后，通过基于模型的变换将波形彼此最佳拟合来估计参数。最后，由参数指定作为血压函数的PTT。该技术在动物和患者中通过多种方式进行了评估，包括其估计的PTT-血压函数作为将PTT校准到血压的个体特异性曲线的能力。
在基线期由该技术得出的校准曲线在广泛改变平均血压的血流动力学干预期间，平均血压的偏差和精度误差分别为5.1±0.9和6.6±1.0 mmHg。
新技术可能首次允许从近端和远端波形估计整个心动周期的PTT值。
该技术可能潜在地应用于改善动脉僵硬度监测并有助于实现无袖带血压监测。
