Strain Gauge Pulse Transit Time Blood Pressure Monitoring

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Solution Overview

Problem

Conventional methods for monitoring blood pressure and heart rate variability, such as photoplethysmography and sphygmomanometers, are limited by sensitivity to motion and lack of continuous measurements, making them unreliable for dynamic activities and providing poor reliability in arterial pressure measurements.

Innovation Solution

A computer-implemented method using semiconductor strain gauge sensors to record pulse transit time and waveform, combined with ECG signals, to determine arterial pressure continuously and non-invasively, enabling reliable monitoring of heart rate variability and blood pressure even during motion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If photoplethysmography and sphygmomanometers are used for blood pressure monitoring, then blood pressure measurement is possible, but sensitivity to motion makes them unreliable during dynamic activities

Engineering Contradiction:

Improvereliability of blood pressure measurementVSAvoidsensitivity to motion

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces conventional mechanical/optical monitoring systems (sphygmomanometers, photoplethysmography) with semiconductor strain gauge sensors that directly measure arterial wall deformation. This substitution eliminates motion sensitivity issues because the strain gauges measure local arterial strain rather than relying on optical detection or mechanical cuff inflation that are disrupted by body movement.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the measurement parameter from indirect optical or mechanical signals to direct mechanical strain measurements of the arterial wall. By measuring strain (deformation) of the artery itself through semiconductor strain gauges, the system obtains reliable blood pressure data even during motion, as the strain measurement directly reflects arterial pressure changes regardless of body movement.

Inventive Principle:

Principle #35Parameter changes

2Duration of action of stationary object

If conventional monitoring methods are used, then blood pressure can be measured, but continuous measurements are not provided

Engineering Contradiction:

Improvecontinuous measurement capabilityVSAvoidmeasurement continuity

Core Design Contradiction:

Duration of action of stationary objectVSProductivity

Solution Approach 1:

The patent implements continuous blood pressure monitoring by having the semiconductor strain gauge sensor continuously measure arterial wall strain in real-time. Unlike conventional methods that provide intermittent measurements, the strain gauge system continuously tracks arterial deformation throughout the measurement period, enabling uninterrupted monitoring of blood pressure dynamics.

Inventive Principle:

Principle #20Continuity of useful action

3Reliability

If semiconductor strain gauge sensors are used to measure pulse transit time and waveform, then continuous and reliable arterial pressure estimation is achieved, but device complexity increases

Engineering Contradiction:

Improvereliability of arterial pressure estimationVSAvoidcomplexity of sensing system

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the blood pressure sensing function with the pulse waveform detection function into a single integrated semiconductor strain gauge sensor system. By combining these measurements from one sensor rather than using separate devices, the system achieves reliable arterial pressure estimation while minimizing the increase in device complexity.

Inventive Principle:

Principle #5Merging (Combining)

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

The method provides continuous, reliable, and non-invasive estimation of systolic and diastolic arterial pressure, overcoming the limitations of existing technologies by using semiconductor strain gauge sensors to measure pulse transit time and waveform, allowing for accurate monitoring of blood pressure and heart rate variability in real-time.

Implementation Method 1

semiconductor strain gauge sensors to record pulse transit time and waveform

Methodology Applied

Scientific EffectPiezoresistive effect: Piezoresistive Effect

Data Source

PatentUS11246496B2Heart rate and blood pressure monitoring biosensors

Publication Date: 2022.02.15 INTERNATIONAL BUSINESS MACHINE CORPORATION

AI summary

Embodiments of the present invention are directed to a systems and methods for registration of pulse wave signal and determining arterial pressure. A non-limiting example of the system includes a strain gauge sensor. A non-limiting example of the method includes receiving, to a processor, a first pressure pulse signal from a first strain gauge sensor. The method also includes receiving, to the processor, a second pressure pulse signal from a second strain gauge sensor. The method also includes determining a pulse transit time between the first strain gauge sensor and the second strain gauge sensor based at least in part upon the first pressure pulse signal and the second pressure pulse signal. The method also includes determining an arterial pressure based at least in part upon the pulse transit time.