Neurogenic Baroreflex Sensitivity Measurement via Finger Pulse Wave

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Solution Overview

Problem

Existing methods for measuring neurogenic baroreflex sensitivity, such as the echo method, are unsuitable for clinical practice due to the need for patients to remain still, making it difficult to accurately measure pulsation changes in the carotid blood vessel diameter, and they rely on vascular stiffness, leading to inaccurate results.

Innovation Solution

A neurogenic baroreflex sensitivity measurement device and method that acquires pulse wave data from an artery, calculates normalized pulse volume, and detects baroreflex series based on continuous changes in both pulse volume and beat interval, calculating sensitivity as the slope of a regression line between these parameters, independent of blood vessel hardness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the echo method is used to measure pulsation change of carotid blood vessel diameter, then neurogenic baroreflex sensitivity not dependent on vascular stiffness can be measured, but the patient needs to rest with ultrasonic probe fixed to the neck, making measurement extremely unsuitable for clinical practice

Engineering Contradiction:
Improveneurogenic baroreflex sensitivity measurement accuracyVSAvoidmeasurement ease for clinical practice
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The invention extracts the useful information (baroreflex sensitivity) from an alternative source (finger pulse wave) rather than using the original source (carotid blood vessel diameter). By measuring pulse wave at the finger instead of directly measuring carotid vessel diameter, the system achieves the same measurement goal without the operational difficulties of fixing an ultrasonic probe to the neck.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses the finger pulse wave as an intermediary to indirectly measure baroreflex sensitivity. Instead of directly measuring carotid vessel diameter changes, the system measures pulse wave characteristics at the finger, which serve as a mediator to reflect the underlying baroreflex function without requiring direct carotid measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If blood pressure measurement is used to assess baroreflex sensitivity, then measurement can be performed, but the result depends on vascular stiffness and is not accurately measured

Engineering Contradiction:
Improvemeasurement easeVSAvoidbaroreflex sensitivity accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The invention replaces the mechanical blood pressure measurement system with an optical pulse wave measurement system. By using photoplethysmography to detect pulse wave characteristics instead of mechanical blood pressure measurement, the system eliminates the confounding effect of vascular stiffness on the measurement results.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the measurement parameter from blood pressure to pulse wave characteristics (specifically the derivative of pulse wave). By measuring the rate of change of pulse wave amplitude rather than static blood pressure values, the system captures dynamic information about baroreflex function that is independent of vascular stiffness.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enables simple and objective measurement of neurogenic baroreflex sensitivity not dependent on blood vessel hardness, providing a reliable index of neurogenic baroreflex function unaffected by sympathetic nervous system activity, with high reliability and accuracy, allowing for comparison between individuals and grasping the tendency of neurogenic baroreflex sensitivity.

Implementation Method 1

a pulse-wave detecting unit that detects pulse wave data of an artery

Methodology Applied
Scientific EffectPulse wave propagation: Vibration

Data Source

PatentEP2979632B1Neurogenic baroreflex sensitivity measurement device, neurogenic baroreflex sensitivity measurement program and neurogenic baroreflex sensitivity measurement method
Publication Date: 2020.12.16 SAPPORO MEDICAL UNIVERSITY
  • EP2979632B1 patent drawingFigure 1
  • EP2979632B1 patent drawingFigure 2
  • EP2979632B1 patent drawingFigure 3

AI summary

[Problem] To provide a neurogenic baroreflex sensitivity measurement device, neurogenic baroreflex sensitivity measurement program and neurogenic baroreflex sensitivity measurement method capable of easily and objectively measuring neurogenic baroreflex sensitivity that is not dependent on vascular hardness without using blood pressure or pulsations in the diameter of the carotid artery. [Solution] The neurogenic baroreflex sensitivity measurement device comprises: a pulse wave data-acquiring unit (41) for acquiring pulse wave data of an artery; a normalized pulse wave volume-calculating unit (42) for calculating a normalized pulse wave volume on the basis of the pulse wave data; a pulse interval-acquiring unit (43) for acquiring pulse intervals corresponding to the pulse wave data; a baroreflex series-detecting unit (44) for detecting baroreflex series in which the normalized pulse wave volume and pulse interval both increase or decrease for at least three beats in a row; and a neurogenic baroreflex sensitivity-calculating unit (45) for calculating the slope of a regression line representing the correlation between the normalized pulse wave volume and the pulse interval in a baroreflex series as the neurogenic baroreflex sensitivity, which is an index representing the neurogenic baroreflex function.