Optical Blood Pressure Monitoring via Plethysmographic Signal Segmentation

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Solution Overview

Problem

Current methods for determining systolic and diastolic blood pressure, particularly those using inflatable cuffs, are invasive, inconvenient, and prone to inaccuracies, especially for older individuals and those with damaged blood streams, and lack the ability for continuous, non-invasive monitoring.

Innovation Solution

The method involves processing plethysmographic curves obtained through non-invasive light transmission and reflection to digitize, filter, and segment data, determining blood pressure values without the need for cuffs, using a device with a communication module that wirelessly connects to sensors and a supervising unit, allowing for continuous or one-time measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If oscillometric method with inflatable cuff is used, then blood pressure can be measured, but measurement accuracy deteriorates for older individuals and those with damaged blood streams

Engineering Contradiction:
Improveblood pressure measurement accuracyVSAvoidapplicability to different patient groups
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent replaces the mechanical inflatable cuff system with an optical measurement system using photodetectors and light sources. This substitution eliminates the mechanical compression that causes measurement errors in vulnerable populations, enabling accurate blood pressure measurement through optical detection of pulse wave characteristics in the finger.

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

Solution Approach 2:

The patent changes the measurement parameter from mechanical pressure detection to optical parameter detection. By measuring light absorption and reflection changes in the finger tissue during the cardiac cycle, the system derives blood pressure values without mechanical intervention, improving accuracy for older individuals and those with compromised blood flow.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If inflatable cuff methods are used, then blood pressure measurement is achieved, but subject burden increases due to frequent inflation procedures

Engineering Contradiction:
Improveblood pressure measurement capabilityVSAvoidsubject convenience
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the cumbersome mechanical cuff inflation/deflation system with a simple optical sensor placed on the finger. This eliminates the need for repeated mechanical interventions, making the measurement process comfortable and convenient for subjects while maintaining measurement capability.

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

Solution Approach 2:

The measurement device performs continuous automatic monitoring without requiring subject participation or manual operation. The photodetectors continuously detect pulse wave characteristics and automatically calculate blood pressure values, providing effortless measurement for the subject.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If oscillometric method with cuff is used, then blood pressure values can be obtained, but measurement repeatability deteriorates due to slow bloodstream return to rest regime

Engineering Contradiction:
Improveblood pressure value assessmentVSAvoidmeasurement repeatability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical cuff that disrupts blood flow with a non-intrusive optical sensing system. This allows continuous monitoring of pulse wave characteristics without interfering with normal blood circulation, enabling repeated measurements that return to baseline conditions immediately, thus improving measurement repeatability.

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

4Reliability

If continuous monitoring is implemented with traditional methods, then health monitoring capability is improved, but energy consumption increases making continual monitoring impossible

Engineering Contradiction:
Improvecontinuous health monitoring capabilityVSAvoiddevice energy consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent replaces energy-intensive mechanical pumping systems with passive optical detection. The photodetectors require minimal energy to detect light absorption changes in the finger tissue, enabling continuous monitoring with very low power consumption suitable for battery-operated portable devices.

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

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

This approach provides accurate, repeatable, and non-invasive blood pressure measurements with lower energy consumption, suitable for long-term use, reducing the burden on the subject and improving measurement reliability, especially for older individuals and those with compromised blood flow.

Implementation Method 1

processing plethysmographic curves obtained through non-invasive light transmission and reflection

Methodology Applied
Scientific EffectLight transmission: Light

Implementation Method 2

processing plethysmographic curves obtained through non-invasive light transmission and reflection

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3010400B1A method of determining systolic and diastolic blood pressure and the unit for this method
Publication Date: 2019.07.31 CZECH TECHN UNIVERZITY IN PRAGUE FACULTY OF ELECTRICAL ENG DEPT OF TELECOMM ENG
  • EP3010400B1 patent drawingFigure 1~2
  • EP3010400B1 patent drawingFigure 3
  • EP3010400B1 patent drawingFigure 4

AI summary

The method of determining systolic and diastolic blood pressure where the set of received data of each curve of the plethysmographic curve gained from the unit for monitoring the life functions in a shape of the ring and/or the earring is divided into individual segments that respond to one heartbeat of the measured subject and after processing there are selected and recalculated segments meeting the defined criteria. The unit for monitoring and measuring the life functions comprises a supporting construction in a shape of a ring (29) and/or an earring (39).