A Non-invasive Radial Arterial Compliance Measuring Method using Bio-Impedance

Area of Science:

• Biomedical Engineering
• Cardiovascular Physiology
• Wearable Sensor Technology

Background:

• Arterial compliance is a key indicator of cardiovascular disease.
• Radial arterial compliance (RAC) is significant in pathophysiological studies.
• Bio-Impedance (Bio-Z) offers non-invasive monitoring of blood volume changes via wearable sensors.

Purpose of the Study:

• To propose and validate a Bio-Z based technique for long-term RAC measurements.
• To analyze the relationship between distensibility, blood pressure, and compliance with mean arterial pressure.
• To introduce a novel Bio-Z based compliance index (DBZI) for continuous and unobtrusive sensing.

Main Methods:

• Utilized Bio-Impedance (Bio-Z) signals for monitoring blood volume changes.
• Controlled blood flow, similar to the oscillometric method, to analyze distensibility-BP and compliance-MAP relations.
• Developed and tested a Bio-Z based compliance index (DBZI) in four healthy participants over seven days.

Main Results:

• Demonstrated consistency and repeatability of Bio-Z based RAC measurements over seven days.
• The mean difference between beat-by-beat compliance and DBZI was 0.17 mOhm/mmHg, with a standard deviation of 0.20 mOhm/mmHg.
• The DBZI tracked Bio-Z based compliance with a mean error of 9.72% and standard deviation of 11.67% compared to a gold standard.

Conclusions:

• The proposed Bio-Z based technique is a consistent and repeatable method for long-term RAC monitoring.
• The developed DBZI shows promise for continuous and unobtrusive assessment of arterial compliance.
• This technology can aid in early detection and management of cardiovascular conditions.