OBJECTIVES Changes of vasoconstriction may be measured non-invasively using pulse transit time. This study assessed the sensitivity, test-retest reliability and validity of pulse transit time during vasoconstriction provocation and active standing, and the predictive value of pulse transit time for blood pressure drop. METHODS Fifty-five younger (age < 65 years) and 31 older adults (age > 70 years) underwent electrocardiography, wrist and finger photoplethysmography and continuous blood pressure and total peripheral resistance measurements during vasoconstriction provocation using a cold pressor test (21 younger adults), or active stand tests (all other participants). Pulse transit time was defined as the time lag between the electrocardiography R-peak and the peak in the photoplethysmography first derivative; sensitivity as a significant decrease relative to baseline; test-retest reliability as the intra class correlation between different repeats of the same test; validity as the association between peripheral resistance and pulse transit time; predictive value as the association between supine resting pulse transit time and mean arterial pressure drop during active standing. RESULTS Finger pulse transit time was sensitive and reliable (ICC 0.2-0.8) during vasoconstriction provocation, but wrist pulse transit time was poorly reliable (ICC 0-0.5); only finger pulse transit time was sensitive to and reliable (ICC 0.4-0.8) during active standing in both younger and older adults. Finger pulse transit time was not associated with total peripheral resistance. Supine resting pulse transit time had predictive value for blood pressure drop during active standing in older adults (β -0.16; p 0.025). CONCLUSIONS Pulse transit time was sensitive to and reliable during vasoconstriction provocation and active standing, but did not significantly differ between younger and older adults. Pulse transit time could not be demonstrated to particularly reflect vasoconstriction, but it had predictive value for blood pressure drop during active standing.

中文翻译：

---

脉搏传播时间可作为年轻人和老年人的血管收缩的代表。

目的可以使用脉冲传输时间无创地测量血管收缩的变化。本研究评估了血管收缩激发和主动站立时脉搏穿越时间的敏感性，重测信度和效度，以及脉搏穿越时间对血压下降的预测价值。方法55名年轻（年龄<65岁）和31名成年人（年龄> 70岁）进行了心电图检查，腕部和手指光体积描记术，并通过冷压试验在持续性血管收缩过程中测量了血压和总外周阻力，其中21名年轻成年人或有效的标准测试（所有其他参与者）。脉冲传播时间定义为心电图R峰与光电容积描记法一阶导数的峰值之间的时间差；灵敏度相对于基线显着降低；重测信度，即同一测试的不同重复之间的类内相关性；作为外围电阻与脉冲传输时间之间的关联的有效性；预测值是仰卧静息脉冲传播时间与主动站立期间平均动脉压下降之间的关联。结果在血管收缩过程中，手指脉搏的通过时间敏感且可靠（ICC 0.2-0.8），而腕部脉搏的通过时间则较差（ICC 0-0.5）。在活跃的站立过程中，无论年轻人还是老年人，只有手指脉冲的传播时间对敏感且可靠（ICC 0.4-0.8）。手指脉冲的传输时间与总的外周阻力无关。仰卧位静息脉冲传播时间对老年人主动站立期间的血压下降具有预测价值（β-0.16； p 0.025）。结论在血管收缩激发和积极站立时，脉冲渡越时间对敏感和可靠，但在年轻人和老年人之间没有显着差异。脉搏传播时间不能证明特别反映血管收缩，但对积极站立时的血压下降具有预测价值。