Assessment of Pulse Transit Time for Monitoring Nocturnal Blood Pressure Trends Using a Chest-Based Photoplethysmography Measurement System

Assessment of Pulse Transit Time for Monitoring Nocturnal Blood Pressure Trends Using a Chest-Based Photoplethysmography Measurement System

<Text wird generiert, bitte warten...>
Task Description

The aim of this master's thesis is the further development and software-based optimization of an existing chest-based photoplethysmography (PPG) measurement system for continuous, non-invasive monitoring of nocturnal blood pressure trends. Building on an existing experimental setup, the signal quality of the optical measurement is to be further improved, and methods for the robust determination of pulse transit time (PTT) are to be developed, optimized and evaluated. The focus lies on optimizing the optical sensor configuration, reliably extracting relevant features from ECG and PPG signals, and investigating their potential for continuously estimating the nocturnal blood pressure profile and nocturnal blood pressure dipping.

The thesis comprises the following subtasks:

1. Optimization of measurement settings

  • Conducting continuous measurement series to analyze the current system behavior

  • Investigating the influence of relevant register parameters (e.g., LED intensity, gain)

  • Identifying optimal parameter configurations within the existing hardware limitations

2. Optimization of an existing algorithm for pulse transit time determination

  • Analyzing the current implementation and identifying remaining sources of error

  • Optimizing ECG and PPG signal processing to improve PTT estimation

  • Improving foot point detection in the PPG signal using suitable signal processing methods

  • Developing robust methods for detecting and handling erroneous PTT values

  • Conducting extensive measurement series to parameterize and validate the methods

  • Assessing the impact of the optimizations on the stability and accuracy of the resulting PTT values

  • Investigating the suitability of the optimized PTT calculation for capturing nocturnal blood pressure trends

3. Analysis of nocturnal blood pressure trends

  • Investigating the suitability of PTT-based features for capturing nocturnal blood pressure trends

  • Analyzing the potential for assessing nocturnal blood pressure dipping (dipping behavior)

4. Evaluation

  • Acquiring measurement data under various experimental conditions

  • Analyzing robustness against motion artifacts and physiological interference

  • Assessing signal quality and the stability of the extracted features

  • Investigating the suitability of PTT and PWF features for continuous blood pressure estimation

  • Comparing different signal processing and feature extraction methods

5. Written thesis

6. Final presentation

Expected Results

A software-optimized chest-based PPG measurement system with improved raw signal behavior and a robust, reliable pulse transit time calculation. The developed methods should enable continuous monitoring of nocturnal blood pressure trends and support the assessment of nocturnal blood pressure dipping. The thesis should demonstrate to what extent a chest-based PPG measurement system, combined with optimized PTT determination, can serve as a basis for long-term, non-invasive monitoring of nocturnal blood pressure behavior.