Objective: We attempt to reconstruct brachial arterial pressure (BAP) waves from finger arterial pressure waves measured using the vascular unloading technique without arm-cuff calibration. A novel method called twolevel optimization (TOP) strategy is proposed as follows. Methods: We first derive a simplified transfer function (TF) based on a tube-load model with only two parameters to be estimated, a coefficient B and a time delay Δt. Then, at level one, two minimization problems are formulated to estimate the optimal coefficient Bopt and time delay Δtopt. Then, we can derive an optimal TF hopt(t). However, this derivation requires true (or reference) BAP waves. Therefore, at level two, we apply multiple linear regression (MLR) to further model the relationship between the derived optimal parameters and subjects' physiologic parameters. Hence, eventually, one can estimate coefficient BMLR and time delay ΔtMLR from subject's physiologic parameters to derive the MLR-based TF hMLR(t) for the BAP reconstruction. Results: Twenty-one volunteers were recruited for the data collection. The mean ± standard deviation of the root mean square errors between the reference BAP waves and the BAP waves reconstructed by hopt(t), hMLR(t), and a generalized transfer function (GTF) were 3.46 ± 1.42 mmHg, 3.61 ± 2.28 mmHg, and 6.80 ± 3.73 mmHg (significantly larger with p <; 0.01), respectively. Conclusions: The proposed method can be considered as a semi-individualized TF which reconstructs significantly better BAP waves than a GTF. Significance: The proposed TOP strategy can potentially be useful in more general reconstruction of proximal BP waves.

中文翻译：

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使用两级优化策略从连续手指动脉压重建连续肱动脉压


目的：我们尝试根据使用血管卸载技术测量的手指动脉压力波重建肱动脉压力（BAP）波，而无需臂带校准。提出了一种称为双层优化（TOP）策略的新方法如下。方法：我们首先基于管负载模型导出简化的传递函数（TF），该模型仅需要估计两个参数：系数 B 和时间延迟 Δt。然后，在第一级，制定两个最小化问题来估计最优系数 Bopt 和时间延迟 Δtopt。然后，我们可以导出最优的 TF hopt(t)。然而，这种推导需要真实（或参考）BAP 波。因此，在第二级，我们应用多元线性回归（MLR）来进一步建模导出的最佳参数与受试者生理参数之间的关系。因此，最终，人们可以根据受试者的生理参数估计系数 BMLR 和时间延迟 ΔtMLR，以导出用于 BAP 重建的基于 MLR 的 TF hMLR(t)。结果：招募了 21 名志愿者来收集数据。参考 BAP 波与由 hopt(t)、hMLR(t) 和广义传递函数 (GTF) 重建的 BAP 波之间的均方根误差的平均值±标准差分别为 3.46 ± 1.42 mmHg、3.61 ± 2.28 mmHg 、和 6.80 ± 3.73 mmHg（p < 时明显更大；0.01）。结论：所提出的方法可以被认为是一种半个性化 TF，它重建的 BAP 波明显优于 GTF。意义：所提出的 TOP 策略可能有助于更一般地重建近端 BP 波。