Optical Vein Hemoglobin Measurement with Respiratory Signal Filtering

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Solution Overview

Problem

Existing methods for measuring hemoglobin-related information, such as oxygen saturation, in veins are invasive, burdensome, risky, and unstable, particularly for newborns and children, and cannot selectively obtain vein-specific information using light.

Innovation Solution

A concentration measurement apparatus and method that uses light input and detection units to obtain hemoglobin-related information, including total hemoglobin concentration and oxygen saturation, with filter processing to extract respiratory-derived components from the detection signal, enabling non-invasive vein-specific measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If invasive methods such as indwelling a catheter in the vein are used, then hemoglobin-related information of veins can be obtained, but burden and risk of the subject increase and measurement stability deteriorates

Engineering Contradiction:
Improvehemoglobin-related information of veinsVSAvoidmeasurement stability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the mechanical invasive method (catheter indwelling) with an optical measurement system. The light input unit emits light that penetrates the skin and measures hemoglobin-related information in veins non-invasively, eliminating the need for physical catheter insertion while maintaining measurement capability.

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

Solution Approach 2:

The patent uses light as an intermediary medium to access vein information without direct contact. The light input unit and light detection unit use light propagation through tissue as a mediator to obtain hemoglobin-related information from veins, avoiding direct mechanical intrusion into the blood vessel.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If invasive methods such as indwelling a catheter in the vein are used, then hemoglobin-related information of veins can be obtained, but the method is particularly difficult to apply to newborn and child

Engineering Contradiction:
Improvehemoglobin-related information of veinsVSAvoidapplicability to newborn and child
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent replaces the mechanical invasive method (catheter indwelling) with an optical measurement system. The light input unit emits light that penetrates the skin and measures hemoglobin-related information in veins non-invasively, eliminating the need for physical catheter insertion while maintaining measurement capability.

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

Solution Approach 2:

The patent enables the measurement system to work passively on the subject without requiring complex procedural steps. The light input unit and light detection unit automatically measure hemoglobin-related information through the skin, making the process as simple as placing a sensor on the skin surface, which is easily applicable to newborns and children.

Inventive Principle:
Principle #25Self-service

3Quantity of substance

If the entire measurement target portion is irradiated with light, then hemoglobin-related information of entire tissue including arteries and veins is obtained, but hemoglobin-related information of veins specifically cannot be obtained

Engineering Contradiction:
Improvehemoglobin-related informationVSAvoidvein-specific information
Core Design Contradiction:
Quantity of substanceVSLoss of information

Solution Approach 1:

The patent extracts vein-specific information from the mixed signal containing both arterial and venous hemoglobin information. By using the temporal relative change amount of hemoglobin concentration and applying filter processing to remove low-frequency components, the system isolates and extracts the venous component from the overall tissue measurement.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses dynamic temporal changes in hemoglobin concentration to differentiate between arterial and venous components. By analyzing the temporal relative change amount and applying frequency filtering to remove slow-varying low-frequency components, the system dynamically separates venous information from the combined arterial-venous signal.

Inventive Principle:
Principle #15Dynamics

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 non-invasive, stable, and accurate measurement of hemoglobin-related information in veins by selectively extracting respiratory-derived components, overcoming the limitations of invasive methods.

Implementation Method 1

a light input unit that inputs measurement light to a measurement target portion; a light detection unit that detects the measurement light propagated inside the measurement target portion, and generates a detection signal according to an intensity of the measurement light

Methodology Applied
Scientific EffectLight absorption and detection: Absorption (EM radiation)

Data Source

PatentEP3895611B1Concentration measurement device and concentration measurement method
Publication Date: 2025.10.15 HAMAMATSU PHOTONICS KK
  • EP3895611B1 patent drawingFigure 1
  • EP3895611B1 patent drawingFigure 2(a)~2(b)
  • EP3895611B1 patent drawingFigure 3

AI summary

A concentration measurement apparatus 1 includes a light input unit for inputting measurement light to a measurement target portion 51, a light detection unit for detecting the measurement light propagated inside the measurement target portion 51, and generating a detection signal according to an intensity of the measurement light, and a calculation unit for obtaining hemoglobin-related information based on the detection signal. The calculation unit performs filter processing of extracting a component derived from respiration among frequency components included in the detection signal, the hemoglobin-related information, or a numerical value appearing in a calculation process of the hemoglobin-related information for obtaining the hemoglobin-related information in a vein of the measurement target portion. Thus, a concentration measurement apparatus and a concentration measurement method capable of non-invasively obtaining hemoglobin-related information of a vein using light are realized.