Methods for Monitoring Cardiovascular Parameters in the Neck Region

Abstract

This diploma thesis deals with the feasibility of non-invasive cardiovascular monitoring in the neck region using piezoelectric sensors. The theoretical part summarizes the physiological background of pulse-wave generation and propagation, the principle of the piezoelectric effect, and current approaches to mechanical sensing of vascular activity. The experimental part includes the design and testing of a phantom flow system, measurements using different types of piezoelectric sensors, and subsequent recordings on human volunteers in the neck region. The work also includes the design of an analogue signal-conditioning stage and verification of an ESP32-based acquisition chain. The acquired signals were processed in MATLAB. The processing pipeline included filtering, synchronization with ECG, pulse-cycle segmentation, normalization, and derivative-based waveform analysis. The main focus was placed on parameters derived from the second derivative of the pulse wave, especially A–E points, the b/a, c/a, d/a, and e/a ratios, and the Vascular Aging Index (VAI). The results showed that piezoelectric sensors are able to detect mechanically transmitted pulsatile activity both on a phantom and in human measurements. At the same time, signal quality was strongly affected by sensor placement, contact pressure, mechanical fixation, and motion or muscle artefacts. Therefore, the proposed system should be interpreted primarily as a feasibility and technical verification study. The thesis identifies the main technical limitations of the measurement setup and provides recommendations for further development of wearable systems for cardiovascular monitoring.