Electrode Placement Strategies for the Measurement of Radial Artery Bioimpedance: Simulations and Experiments

Continuous cardiac output is a significant matter that must be considered in monitoring the functioning of cardiovascular system. A noninvasive sensing system that is based on measuring electrical bioimpedance variations of radial artery is proposed to evaluate the physical condition of a patient. To optimize the signal acquisition, different electrode placement strategies are compared with the goal of finding the most suitable ones. The finite-element method (FEM) simulation of sensitivity distribution and experimental measurements on radial artery are performed for experimenting circular and distal electrode placements. Importantly, also the modified electrode placement strategies, guided by the idea of focused impedance method (FIM), are investigated. To reduce the number of electrodes in measurement setup, its novel version is proposed: a five-electrode FIM strategy. The efficiency of the proposed strategy can be seen in the reduced amount of required number of electrodes: the smaller area of electrode-skin contact interface results in smaller influence of uncertainties. Moreover, the reduced number of electrodes contributes to benefit through developing simpler instrumentation having lower energy consumption and cheaper manufacturing costs. The results show the advances of the proposed novel five-electrode FIM strategy for measuring the pulsating volume of blood in radial artery with the goal of determining the central aortic pressure (CAP) of blood.

Automated summary

Continuous cardiac output is a significant matter that must be considered in monitoring the functioning of the cardiovascular system. A noninvasive sensing system based on measuring electrical bioimpedance variations of the radial artery is proposed to evaluate the physical condition of a patient. The novel five-electrode FIM strategy shows advances in measuring the pulsating volume of blood in the radial artery with the goal of determining the central aortic pressure (CAP) of blood.