Spectrophotometric Sensor Adjusting Interrogation Settings
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Solution Overview
Problem
Conventional non-invasive methods for determining biological tissue oxygenation, such as near-infrared spectroscopy, face inaccuracies when tissue optical properties deviate from assumed constants, particularly in populations with abnormal tissue characteristics due to disease, injury, or abnormal anatomy, leading to erroneous oxygen saturation readings.
Innovation Solution
A spectrophotometric sensor system that adjusts its interrogation settings based on detected light attenuation values, using a first or second setting depending on whether the attenuation values fall within or outside a predefined range, to accurately determine blood oxygen parameters by accounting for individual tissue optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional non-invasive methods assume constant tissue optical properties, then the measurement process is simplified and faster, but accuracy deteriorates when tissue optical properties are abnormal
Solution Approach 1:
The system performs preliminary characterization of tissue optical properties by measuring attenuation at multiple wavelengths before determining oxygen saturation. This preliminary action allows the system to adapt its interrogation settings based on the subject's specific tissue properties, resolving the contradiction between simplified constant assumption and accurate measurement for abnormal tissues.
Solution Approach 2:
The system changes the interrogation parameters (wavelengths and/or modulation frequencies) based on the measured tissue attenuation characteristics. By dynamically adjusting these parameters according to the subject's tissue properties, the system maintains high accuracy across diverse tissue types without requiring complex real-time adaptation during oxygen saturation measurement.
2Measurement precision
If the system uses a fixed interrogation setting for all subjects, then the device complexity is reduced, but measurement precision deteriorates for subjects with abnormal tissue optical properties
Solution Approach 1:
The system performs preliminary measurements at multiple wavelengths to characterize tissue optical properties before determining oxygen saturation. This preliminary characterization enables the system to select appropriate interrogation settings tailored to each subject's tissue properties, achieving high precision without complex real-time adjustments during the actual oxygen saturation measurement.
Solution Approach 2:
The system uses feedback from the preliminary attenuation measurements to determine the appropriate interrogation settings for oxygen saturation measurement. By incorporating this feedback loop, the system automatically adapts to individual tissue characteristics, maintaining measurement precision while managing device complexity through automated parameter selection.
3Measurement precision
If the system measures attenuation at multiple wavelengths to characterize tissue properties, then measurement precision for abnormal tissues improves, but the time required for measurement increases
Solution Approach 1:
The system performs preliminary attenuation measurements at multiple wavelengths quickly to characterize tissue optical properties, then uses this information to optimize the oxygen saturation measurement. By completing the characterization phase efficiently upfront, the system minimizes total measurement time while maintaining high precision for abnormal tissues.
Solution Approach 2:
The system changes the interrogation parameters based on the preliminary tissue characterization to optimize subsequent measurements. By selecting the most efficient wavelengths and modulation frequencies after the preliminary phase, the system reduces the time required for oxygen saturation measurement while maintaining high 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
The system provides accurate blood oxygen parameter values, including oxygen saturation, by compensating for excessive light absorption in tissues with abnormal optical properties, improving the reliability of non-invasive tissue oximetry even in subjects with altered tissue conditions.
Implementation Method 1
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
These methods, and others known within the prior art, utilize variants of the Beer-Lambert law to account for optical attenuation in tissue
Implementation Method 4
account for optical attenuation in tissue at a particular wavelength
Implementation Method 5
Numerous physical phenomena may collectively cause light attenuation, including light scattering and absorptive phenomena
Data Source
AI summary
An apparatus and method for non-invasively determining a blood oxygen parameter value of a subject's tissue is provided. An embodiment of the method includes the steps of: a) providing a spectrophotometric sensor that includes a processing portion and a transducer, b) detecting at least a portion of transmitted light after passage through the subject's tissue and producing initial signal data from the detected light; and c) using the processing portion to: (i) determine a value representative of an attenuation of at least one wavelength of light detected; (ii) determine whether the representative attenuation value is outside a predefined range of attenuation values; and (iii) determine the blood oxygen parameter value using a first interrogation or an alternate interrogation setting.