[2019] BioZ (bio-impedance) patch for the measurement of thoracic impedance

Wearable sensors are playing a major role in supporting clinical diagnostics and disease management by providing potential long-term biosignal acquisition and real-time data processing. Non-invasive cardiovascular disease monitoring is predominantly based on the recording of electrocardiogram (ECG) signals, in addition to physiological measurements, including pulse, blood pressure, temperature and respiration. More recently, transthoracic bioimpedance (TBI) measurements has been proposed as a promising approach to indirectly measure intrathoracic fluid volume. The measurement of TBI can be useful to monitor fluid build-up in the thorax in patients with heart failure (HF).

The principle of TBI consists on applying an alternating current (between 1mA-5mA) at different frequencies (between 20Hz and 100kHz) through two electrodes and acquire the resulting voltage difference between other two electrodes (tetrapolar configuration). The acquired voltage is proportional to the bioimpedance variation (ΔZ) in the thoracic region. The measured bioimpedance can be measured at a single-frequency or at multi-frequencies and reconstructed using regression analysis.

This project will focus on the development of a low-power wireless patch (BioZ) for TBI monitoring. The patch should estimate, in real-time, a number of parameters, e.g. respiration rate, fluid volume and cardiac output.

Assignment

The development of the BioZ patch will involve the design of:

• Bioimpedance electrodes and optimised electrode configuration (planar array)
• Low-power time-based multichannel impedance readout and wireless unit
• Control system for real-time impedance estimation

The development of the readout electronics will start at system-level (Matlab and Simulink) and will progress to a discrete development of an impedance analyser based on the use of COTS and an FPGA. Partial design of readout blocks in CMOS is possible (knowledge of Cadence required).

Requirements

Interested and motivated MSc student in BME or EE

Contact

dr. Virgilio Valente

Bioelectronics Group

Department of Microelectronics

Last modified: 2019-07-16