NIRS Hemoglobin Monitoring for Continuous Non-Invasive Measurement
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Solution Overview
Problem
Existing non-invasive methods for determining blood circulatory hemoglobin values are affected by physiological parameters and require invasive blood sampling, providing only periodic information rather than continuous monitoring.
Innovation Solution
A near-infrared spectrophotometric (NIRS) sensing device is used to continuously sense tissue, producing signals for determining total hemoglobin (THb) data, with calibration methods to ensure accuracy, including machine learning techniques and evaluation of signal stability and hemodynamic changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive blood sampling is used to determine circulatory hemoglobin values, then measurement precision is improved, but ease of operation deteriorates and productivity decreases
Solution Approach 1:
The patent replaces the mechanical/invasive blood sampling system with an optical detection system. NIRS sensors use near-infrared light to non-invasively measure hemoglobin levels through tissue, eliminating the need for needle punctures and blood draws while maintaining measurement capability through optical absorption spectroscopy
Solution Approach 2:
The patent introduces tissue as an intermediary medium between the NIRS sensor and the circulatory blood. The sensors placed on skin surface detect light attenuation through tissue layers to indirectly measure hemoglobin concentrations in underlying blood vessels, enabling non-invasive measurement while accounting for tissue optical properties
2Measurement precision
If invasive blood sampling is used periodically, then measurement precision is improved, but loss of time increases and productivity decreases
Solution Approach 1:
The patent implements continuous hemoglobin monitoring using NIRS sensors that continuously emit near-infrared light and detect transmitted or reflected light through tissue. This provides real-time, continuous hemoglobin concentration data without the periodic interruptions of invasive sampling, enabling immediate detection of hemoglobin changes
Solution Approach 2:
The patent uses periodic pulsatile blood flow as a natural signal source to enhance continuous monitoring. By detecting hemoglobin changes synchronized with cardiac cycles, the system extracts meaningful hemoglobin concentration information from continuous NIRS signals, combining periodic physiological action with continuous optical measurement
3Ease of operation
If NIRS tissue oximetry is used to monitor tissue hemoglobin, then ease of operation is improved, but measurement precision deteriorates due to physiological parameter variations
Solution Approach 1:
The patent implements feedback mechanisms where NIRS-derived tissue hemoglobin parameters are continuously monitored and used to adjust or validate measurements against expected circulatory hemoglobin values. This feedback loop helps compensate for physiological variations by detecting trends and anomalies that indicate deviations from true circulatory hemoglobin status
Solution Approach 2:
The patent employs multiple NIRS measurement parameters including light attenuation at different wavelengths, pulsatile component analysis, and temporal dynamics of hemoglobin changes. By analyzing multiple parameters simultaneously and their relationships, the system distinguishes between tissue-specific hemoglobin variations and true circulatory hemoglobin changes, improving measurement precision
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 continuous, non-invasive monitoring of blood circulatory hemoglobin with improved accuracy, reducing the need for invasive sampling and providing stable trending of blood constituents.
Implementation Method 1
Near-infrared spectroscopy (NIRS) is an optical spectrophotometric method of continually monitoring tissue parameters
Implementation Method 2
Hemoglobin exposed to light in the near infra-red range has specific absorption spectra that varies depending on its oxidation state
Data Source
AI summary
A method and system for non-invasively determining continuous total hemoglobin data is provided. The method includes a) using a near infra-red spectrophotometric (NIRS) sensing device on a continuous basis to sense a subject's tissue, the sensing producing NIRS signals; and b) determining continuous total hemoglobin (THb) using the produced NIRS signals.