Bassil Kate, Agarwal Anurag
Department of Engineering, University of Cambridge, Trumpington Street, Cambridge CB2 1PZ, United Kingdom.
PNAS Nexus. 2025 Aug 12;4(8):pgaf222. doi: 10.1093/pnasnexus/pgaf222. eCollection 2025 Aug.
High blood pressure (hypertension) is the number one risk factor for premature death. Hypertension is asymptomatic, so blood pressure must be regularly monitored to diagnose it. In auscultatory blood pressure measurement, a patient's systolic (maximum) and diastolic (minimum) blood pressure are inferred from the pressure in an inflatable cuff wrapped around the arm. This technique is the gold standard against which all other noninvasive devices are validated. However, auscultatory measurements systematically underestimate systolic blood pressure and overestimate diastolic blood pressure. Overestimation is attributed to the increased cuff pressure needed to occlude the artery because of the surrounding tissue and arterial stiffness. In contrast, the cause of systolic underestimation, which leads to potentially a third of systolic hypertension cases being missed, has remained unclear. When the cuff is inflated beyond the systolic blood pressure, the blood flow to the vessels downstream of the cuff is cut off. The pressure in these downstream vessels drops to a low plateau. We have developed a novel experimental rig that shows that the low downstream pressure is the key cause of the underestimation of systolic blood pressure. The lower the downstream pressure, the greater the underestimation. Our results yield a simple physical model for the underestimation of systolic pressure in our rig and in the human body. Understanding the physics behind the underestimation of systolic blood pressure paves the way for developing strategies to mitigate this error.
高血压是过早死亡的首要风险因素。高血压没有症状，因此必须定期监测血压以进行诊断。在听诊法测量血压时，通过缠绕在手臂上的充气袖带中的压力来推断患者的收缩压（最大值）和舒张压（最小值）。这种技术是验证所有其他非侵入性设备的金标准。然而，听诊测量会系统性地低估收缩压并高估舒张压。高估是由于周围组织和动脉僵硬导致阻断动脉所需的袖带压力增加。相比之下，收缩压低估的原因一直不明，而这可能导致三分之一的收缩期高血压病例被漏诊。当袖带充气超过收缩压时，流向袖带下游血管的血流被切断。这些下游血管中的压力降至一个较低的平稳水平。我们开发了一种新型实验装置，结果表明下游压力低是收缩压低估的关键原因。下游压力越低，低估程度越大。我们的结果为我们的实验装置以及人体中收缩压低估提供了一个简单的物理模型。理解收缩压低估背后的物理原理为制定减轻这种误差的策略铺平了道路。
