Multi-Wavelength Hemoglobin Measurement via Tissue Compression
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Solution Overview
Problem
Existing pulse oximetry methods struggle to accurately measure blood substance concentrations, especially in patients with impaired circulation or comatose states, as they rely on pulse wave amplitude, which can be weakened, making measurements impossible or inaccurate.
Innovation Solution
A biological signal measuring apparatus using multiple wavelengths to calculate blood-derived light attenuations by subtracting light attenuation differences, eliminating the influence of non-blood tissue, and employing a pressurization mechanism to stabilize tissue thickness for accurate hemoglobin concentration measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pulse oximetry is used to measure blood substance concentrations, then non-invasive measurement is achieved, but measurement accuracy deteriorates when pulse wave amplitude is extremely weak
Solution Approach 1:
The patent extracts and eliminates the influence of non-blood tissue from the light attenuation measurement. By using multiple wavelengths and calculating the difference in light attenuation, the method isolates the blood-derived component, removing the interfering non-blood tissue signals that cause measurement errors in weak pulse conditions.
Solution Approach 2:
The patent transitions from single-wavelength or dual-wavelength measurement to multi-wavelength measurement (N wavelengths where N≥4). This dimensional expansion in the wavelength domain provides additional independent equations to solve for multiple hemoglobin species concentrations, enabling accurate measurement even when pulse wave amplitude is weak.
2Measurement precision
If multiple wavelengths are used to eliminate non-blood tissue influence, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent designs a multi-functional system where the same light source and detector assembly serves multiple wavelengths simultaneously. The single measuring apparatus performs multiple functions: emitting N different wavelengths, detecting light attenuation at each wavelength, and calculating concentrations of multiple hemoglobin species, thereby reducing overall device complexity despite using multiple wavelengths.
Solution Approach 2:
The patent combines the measurement of N different wavelengths into a unified measurement system. By merging the light emission, detection, and calculation processes into a single integrated apparatus, the system achieves accurate multi-component hemoglobin measurement without requiring separate devices for each wavelength or component.
3Reliability
If pressing force is applied to stabilize tissue thickness, then measurement reliability is improved, but patient comfort and tissue safety deteriorate
Solution Approach 1:
The patent applies pressing force only partially - just enough to stabilize tissue thickness and eliminate motion artifacts during measurement, rather than excessive force that would cause discomfort or tissue damage. The pressing is applied temporarily only during the measurement phase, not continuously, balancing reliability improvement with patient comfort.
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 accurate and reliable measurement of oxygenated, reduced, and carbon monoxide hemoglobin concentrations even in impaired circulation states, providing rapid and simple identification of in-blood substances without requiring special probes or preparations.
Implementation Method 1
measuring differences in light attenuation at different wavelengths
Implementation Method 2
acquire light attenuations of N (≥4) kinds of wavelengths... calculate blood-derived light attenuations
Implementation Method 3
employing a pressurization mechanism to stabilize tissue thickness for accurate hemoglobin concentration measurement
Data Source
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AI summary
A biological signal measuring system includes: a light emitter emitting light beams having different N kinds of wavelengths, where N is an integer of four or more; a light receiver, a processor and an outputting section outputting (N-1) identified concentrations. Light attenuations A1, A2, A3,...,An are acquired based on changes of the received light intensities due to pressing of a living tissue at each of the N different wavelengths. The concentrations of the N-1 different components are obtained from differences of light attenuation at different wavelengths, namely A2-A1, A3-A1, etc.