Implantable Impedance Plethysmography

Theodor, Michael; Ruh, Dominic; Ocker, M; Spether, Dominik; Förster, Katharina; Heilmann, Claudia; Beyersdorf, Friedhelm; Manoli, Yiannos; Zappe, Hans; Seifert, Andreas

doi:10.3390/s140814858

Cited by 10 publications

(2 citation statements)

References 18 publications

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“…The Z value is affected by the arterial cross-sectional area (A), shown as follows:where L is the length of the measured segment. Thus, the arterial cross-sectional area or arterial diameter itself proved to be highly correlated with the change in BP value 15,32 . In addition, earlier studies mentioned that the arterial cross-section has a nonlinear relationship to the arterial BP 33,34 .…”

Section: Discussionmentioning

confidence: 93%

Multimodal Wrist Biosensor for Wearable Cuff-less Blood Pressure Monitoring System

Rachim

Chung

2019

Sci Rep

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We propose a multimodal biosensor for use in continuous blood pressure (BP) monitoring system. Our proposed novel configuration measures photo-plethysmography (PPG) and impedance plethysmography (IPG) signals simultaneously from the subject wrist. The proposed biosensor system enables a fully non-intrusive system that is cuff-less, also utilize a single measurement site for maximum wearability and convenience of the patients. The efficacy of the proposed technique was evaluated on 10 young healthy subjects. Experimental results indicate that the pulse transit time (PTT)-based features calculated from an IPG peak and PPG maximum second derivative (f 14 ) had a relatively high correlation coefficient ( r ) to the reference BP, with −0.81 ± 0.08 and −0.78 ± 0.09 for systolic BP (SBP) and diastolic BP (DBP), respectively. Moreover, here we proposed two BP estimation models that utilize six- and one-point calibration models. The six-point model is based on the PTT, whereas the one-point model is based on the combined PTT and radial impedance (Z). Thus, in both models, we observed an adequate root-mean-square-error estimation performance, with 4.20 ± 1.66 and 2.90 ± 0.90 for SBP and DBP, respectively, with the PTT BP model; and 6.86 ± 1.65 and 6.67 ± 1.75 for SBP and DBP, respectively, with the PTT-Z BP model. This study suggests the possibility of estimating a subject’s BP from only wrist bio-signals. Thus, the six- and one-point PTT-Z calibration models offer adequate performance for practical applications.

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Section: Discussionmentioning

confidence: 93%

Multimodal Wrist Biosensor for Wearable Cuff-less Blood Pressure Monitoring System

Rachim

Chung

2019

Sci Rep

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“…The use of a triple-layer model [ 19 ] to describe the charge zone results in a relative permittivity of ε r = 17.8 and a Debye length of 0.64 nm (4 to 5 orders of magnitude smaller than the usual tissue thicknesses). Further influence of the intra-arterial blood pressure (depending on volume and flow) on electrical impedance is studied in [ 20 ], although an analytical model explaining this relation was not presented therein and should be object of future work.…”

Section: Methodsmentioning

confidence: 99%

Real-Time Electrical Bioimpedance Characterization of Neointimal Tissue for Stent Applications

Rivas-Marchena

Olmo

Miguel

et al. 2017

Sensors

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To follow up the restenosis in arteries stented during an angioplasty is an important current clinical problem. A new approach to monitor the growth of neointimal tissue inside the stent is proposed on the basis of electrical impedance spectroscopy (EIS) sensors and the oscillation-based test (OBT) circuit technique. A mathematical model was developed to analytically describe the histological composition of the neointima, employing its conductivity and permittivity data. The bioimpedance model was validated against a finite element analysis (FEA) using COMSOL Multiphysics software. A satisfactory correlation between the analytical model and FEA simulation was achieved in most cases, detecting some deviations introduced by the thin “double layer” that separates the neointima and the blood. It is hereby shown how to apply conformal transformations to obtain bioimpedance electrical models for stack-layered tissues over coplanar electrodes. Particularly, this can be applied to characterize the neointima in real-time. This technique is either suitable as a main mechanism for restenosis follow-up or it can be combined with proposed intelligent stents for blood pressure measurements to auto-calibrate the sensibility loss caused by the adherence of the tissue on the micro-electro-mechanical sensors (MEMSs).

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Measurement of Blood Pressure in Conscious Cats and Dogs

Jepson

2020

Hypertension in the Dog and Cat

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Implantable Impedance Plethysmography

Cited by 10 publications

References 18 publications

Multimodal Wrist Biosensor for Wearable Cuff-less Blood Pressure Monitoring System

Multimodal Wrist Biosensor for Wearable Cuff-less Blood Pressure Monitoring System

Real-Time Electrical Bioimpedance Characterization of Neointimal Tissue for Stent Applications

Measurement of Blood Pressure in Conscious Cats and Dogs

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