Improved Vibration-Model-Based Analysis for Estimation of Arterial Parameters From Noninvasively Measured Arterial Pulse Signals

Author(s):  
Md Mahfuzur Rahman ◽  
Najmin Ara Sultana ◽  
Linda Vahala ◽  
Leryn Reynolds ◽  
Zhili Hao

Abstract With the goal of achieving consistence in interpretation of an arterial pulse signal between its vibration model and its hemodynamic relations and improving its physiological implications in our previous study, this paper presents an improved vibration-model-based analysis for estimation of arterial parameters: elasticity (E), viscosity (η), and radius (r0) at diastolic blood pressure (DBP) of the arterial wall, from a noninvasively measured arterial pulse signal. The arterial wall is modeled as a unit-mass vibration model, and its spring stiffness (K) and damping coefficient (D) are related to arterial parameters. Key features of a measured pulse signal and its first-order and second-order derivatives are utilized to estimate the values of K and D. These key features are then utilized in hemodynamic relations, where their interpretation is consistent with the vibration model, to estimate the value of r0 from K and D. Consequently, E, η, and pulse wave velocity (PWV) are also estimated from K and D. The improved vibration-model-based analysis was conducted on pulse signals of a few healthy subjects measured under two conditions: at-rest and immediately post-exercise. With E, r0, and PWV at-rest as baseline, their changes immediately post-exercise were found to be consistent with the related findings in the literature. Thus, this improved vibration-model-based analysis is validated and contributes to estimation of arterial parameters with better physiological implications, as compared with its previous counterpart.

2019 ◽  
Vol 18 (6) ◽  
pp. 1629-1638 ◽  
Author(s):  
Dan Wang ◽  
Leryn Reynolds ◽  
Thomas Alberts ◽  
Linda Vahala ◽  
Zhili Hao

2021 ◽  
Author(s):  
Mahfuzur Rahman ◽  
Najmin Ara Sultana ◽  
Linda Vahala ◽  
Leryn Reynolds ◽  
Zhili Hao

Author(s):  
Dan Wang ◽  
Frank A. Lattanzio ◽  
Mario C. Rodriguez ◽  
Zhili Hao

Abstract In this work, a microfluidic-based tactile sensor was investigated for monitoring changes in the cardiovascular (CV) system of a rabbit caused by phenylephrine. The sensor was fixed on the front right leg of an anesthetized rabbit to measure the arterial pulse signal. Phenylephrine, as a vasoconstrictor, was used to introduce CV changes of the rabbit. Two sensors, one with high sensitivity and the other with low sensitivity, were tested on their suitability for measuring the pulse signals of the rabbit. The sensor with low sensitivity generated clear pulse signals and was further used to monitor the CV changes of the rabbit caused by phenylephrine. An automated sphygmomanometer and an ECG were used to record blood pressure and heart rate for comparison. Three low-dose injections of phenylephrine were sequentially performed on the rabbit. Through model-based analysis of the measured pulse signals, arterial elastic modulus, arterial radius and pulse wave velocity (PWV) were obtained. As compared with the baseline values measured before injection, injections of phenylephrine caused an increase in mean blood pressure (MAP) recorded by the medical instruments, and a decrease in arterial radius (increase in peripheral vascular resistance (PVR)) and an increase in arterial elastic modulus and PWV captured by the tactile sensor. Thus, the tactile sensor was proven to be feasible for monitoring the changes in the CV system caused by phenylephrine.


Author(s):  
Roman Carlo B. Roxas ◽  
Adam T. Harnish ◽  
Dylon N. Johnson ◽  
Camrie M. Stewart ◽  
Dieu Nguyen ◽  
...  

Abstract This paper presents a theoretical study of sensor-artery interaction in arterial pulse signal measurement using a tactile sensor. A measured pulse signal is a combination of the true pulse signal in an artery, the arterial wall, its overlying tissue, and the sensor, under the influence of hold down pressure exerted on the sensor and motion artifact. The engineering essence of sensor-artery interaction is identified as elastic wave propagation in the overlying tissue and pulse signal transmission into the sensor at the skin surface, and different lumped-element models of sensor-artery interaction are utilized to examine how the involved factors affect a measured pulse signal. Achieving ideal sensor-artery conformity is the key for acquiring a measured pulse signal with minimum distortion. Hold-down pressure, sensor design, and overlying tissue collectively contribute to ideal sensor-artery conformity. Under ideal sensor-artery conformity, both the sensor and overlying tissue cause an increase in the measured stiffness of the arterial wall; damping and inertia of the sensor and overlying tissue also affects a measured pulse signal. The theoretical study shows the need to tailor the sensor design for different arteries and individual, and interpret estimated arterial indices with consideration of individual variations as well as instruments used.


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