Subject-Specific Calibration for Blood Oxygen Monitoring
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing non-invasive methods for determining biological tissue oxygenation, such as those using near-infrared spectroscopy, fail to accurately account for the specific optical properties of individual subjects, particularly those with varying skin pigmentation and tissue density, leading to inaccurate blood oxygen saturation measurements.
Innovation Solution
A near-infrared spectrophotometric sensor that transmits light at multiple wavelengths and processes signal data to account for the specific physical characteristics of each subject, generating subject-specific calibration constants to accurately determine blood oxygen saturation levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If subject-independent wavelength independent methods are used, then device complexity is reduced and ease of operation is improved, but measurement precision deteriorates for subjects with varying tissue optical properties
Solution Approach 1:
The patent performs preliminary calibration measurements on each subject to determine their specific tissue optical properties before actual blood oxygen saturation monitoring. This preliminary action captures subject-specific characteristics (skin pigmentation, muscle density, bone structure) and stores them for use during subsequent measurements, thereby improving measurement precision without requiring complex real-time adjustments during operation
Solution Approach 2:
The patent changes the calibration parameters from fixed universal values to subject-specific variable parameters. By measuring and storing individual tissue optical properties (absorption coefficients, scattering coefficients) for each subject, the system adapts the measurement parameters to match the specific physiological characteristics of each patient, resolving the contradiction between simplicity and precision
2Measurement precision
If subject-specific calibration is implemented, then measurement precision is improved for diverse populations, but ease of operation deteriorates due to additional calibration steps
Solution Approach 1:
The system performs self-calibration by automatically measuring the subject's tissue optical properties during the initial sensor placement. The calibration process is integrated into the normal operation workflow, requiring minimal user intervention. The sensor autonomously captures subject-specific characteristics and configures its measurement parameters without requiring manual adjustment or complex user input, thereby maintaining ease of operation while achieving subject-specific precision
Solution Approach 2:
The patent merges the calibration process with the initial sensor placement procedure. Instead of separating calibration as a distinct complex step, the system combines tissue property measurement with the routine sensor attachment workflow, allowing calibration to occur naturally as part of the setup process rather than as an additional burden
3Measurement precision
If wavelength independent assumptions are made, then productivity is improved through faster measurements, but measurement precision deteriorates for subjects with diverse skin pigmentation
Solution Approach 1:
The patent performs preliminary measurement of tissue optical properties at multiple wavelengths during an initial calibration phase. This preliminary action captures the subject's specific wavelength-dependent absorption and scattering characteristics, allowing the system to store these parameters for use during subsequent measurements, thereby enabling both precision and speed
Solution Approach 2:
The system dynamically adjusts measurement parameters based on the subject's specific tissue properties. By determining wavelength-dependent absorption coefficients and scattering coefficients during calibration, the system optimizes the measurement parameters for each subject's unique characteristics, enabling accurate measurements across diverse skin pigments without sacrificing measurement speed during actual monitoring
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 more accurate blood oxygen saturation assessments for subjects with a wide range of physical characteristics by calibrating the sensor based on individual tissue properties, improving measurement accuracy compared to traditional subject-independent methods.
Implementation Method 1
utilize near-infrared spectroscopy (NIRS) techniques for determining the same in particular
Implementation Method 2
utilize variants of the Beer-Lambert law to account for optical attenuation in tissue at a particular wavelength
Implementation Method 3
account for optical attenuation in tissue at a particular wavelength
Implementation Method 4
Bλ represents the wavelength dependent light scattering differential pathlength factor
Data Source
AI summary
According to the present invention, a method and apparatus for non-invasively determining the blood oxygen saturation level within a subject's tissue is provided. The method comprises the steps of: a) providing a spectrophotometric sensor operable to transmit light into the subject's tissue, and to sense the light; b) detecting light after passage through the subject's tissue using the sensor, and producing initial signal data from the light sensed; c) calibrating the sensor to that particular subject using the initial signal data, thereby accounting for the specific physical characteristics of the particular subject's tissue being sensed; and d) using the calibrated sensor to determine the blood oxygen parameter value within the subject's tissue.