Dept. of Electrical and Computer Engineering, Michigan State Univ., East Lansing, MI 48824-1226, USA.
J Appl Physiol (1985). 2011 Dec;111(6):1681-6. doi: 10.1152/japplphysiol.00980.2011. Epub 2011 Sep 29.
Pulse transit time (PTT) is a proven, simple to measure, marker of blood pressure (BP) that could potentially permit continuous, noninvasive, and cuff-less BP monitoring (after an initial calibration). However, pulse arrival time (PAT), which is equal to the sum of PTT and the pre-ejection period, is gaining popularity for BP tracking, because it is even simpler to measure. The aim of this study was to evaluate the hypothesis that PAT is an adequate surrogate for PTT as a marker of BP. PAT and PTT were estimated through the aorta using high-fidelity invasive arterial waveforms obtained from six dogs during wide BP changes induced by multiple interventions. These time delays and their reciprocals were evaluated in terms of their ability to predict diastolic, mean, and systolic BP (DBP, MBP, and SBP) per animal. The root mean squared error (RMSE) between the BP parameter predicted via the time delay and the measured BP parameter was specifically used as the evaluation metric. Taking the reciprocals of the time delays tended to reduce the RMSE values. The DBP, MBP, and SBP RMSE values for 1/PAT were 9.8 ± 5.2, 10.4 ± 5.6, and 11.9 ± 6.1 mmHg, whereas the corresponding values for 1/PTT were 5.3 ± 1.2, 4.8 ± 1.0, and 7.5 ± 2.2 mmHg (P < 0.05). Thus tracking BP via PAT was not only markedly worse than via PTT but also unable to meet the FDA BP error limits. In contrast to previous studies, our results quantitatively indicate that PAT is not an adequate surrogate for PTT in terms of detecting challenging BP changes.
脉搏传输时间 (PTT) 是一种经过验证的、易于测量的血压标志物，它可以实现连续、无创和无袖带的血压监测（经过初始校准后）。然而，脉搏到达时间 (PAT) 作为一种血压跟踪的指标，正越来越受到关注，因为它甚至更容易测量。本研究旨在验证假设，即 PAT 作为血压标志物是 PTT 的一个充分替代指标。通过对六只狗进行的多种干预诱导的广泛血压变化期间获得的高保真有创动脉波形，从主动脉测量 PAT 和 PTT。这些时间延迟及其倒数，以预测每只动物的舒张压、平均压和收缩压 (DBP、MBP 和 SBP) 的能力进行评估。通过时间延迟预测的血压参数与测量的血压参数之间的均方根误差 (RMSE) 被特别用作评估指标。采用时间延迟的倒数往往会降低 RMSE 值。1/PAT 的 DBP、MBP 和 SBP RMSE 值分别为 9.8 ± 5.2、10.4 ± 5.6 和 11.9 ± 6.1mmHg，而 1/PTT 的相应值分别为 5.3 ± 1.2、4.8 ± 1.0 和 7.5 ± 2.2mmHg（P < 0.05）。因此，通过 PAT 跟踪血压不仅明显差于通过 PTT，而且无法满足 FDA 的血压误差限制。与之前的研究不同，我们的结果定量地表明，在检测具有挑战性的血压变化方面，PAT 不是 PTT 的充分替代指标。
