Non-invasive Tissue Oxygenation Estimation via Multi-wavelength Light Absorption
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Solution Overview
Problem
Current medical devices lack the capability to monitor microcirculatory flows in real-time and non-invasively, which is essential for understanding tissue oxygenation and improving patient care, as macrocirculatory optimization alone is insufficient to ensure good tissue oxygenation.
Innovation Solution
A method and device that measure light intensities at multiple wavelengths to estimate local metabolic parameters by calculating concentrations of oxyhemoglobin and deoxyhemoglobin, allowing for the determination of tissue oxygenation and oxygen consumption, using a system of equations and regularized optimization to improve estimation quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If macrocirculatory parameters are optimized, then blood transport from heart to organs is improved, but tissue oxygenation is not guaranteed due to microcirculatory alterations
Solution Approach 1:
The patent segments the monitoring function into two distinct levels: macrocirculatory monitoring (existing capability) and microcirculatory monitoring (new capability). The device separately measures macrocirculatory parameters and microcirculatory parameters, allowing independent optimization of each level without interfering with the other, thus resolving the contradiction between reliability of tissue oxygenation and device complexity.
Solution Approach 2:
The monitoring device is designed with multi-functionality to simultaneously assess both macrocirculatory and microcirculatory parameters. By integrating multiple monitoring functions into a single device, the patent avoids the need for separate complex devices while ensuring comprehensive tissue oxygenation assessment, thereby addressing both reliability and device complexity concerns.
2Loss of information
If microcirculatory flows are monitored in real-time non-invasively, then tissue oxygenation understanding is improved, but measurement precision is challenged due to the small scale of microcirculatory structures
Solution Approach 1:
The patent employs optical indicators (light absorption properties of hemoglobin) as intermediaries to indirectly measure microcirculatory flows. Instead of directly visualizing or measuring the tiny microcirculatory structures, the device uses light as a mediator that interacts with blood components, converting unobservable microcirculatory dynamics into measurable optical signals, thus preserving microcirculatory information while overcoming measurement precision limitations.
Solution Approach 2:
The patent replaces direct mechanical or invasive measurement methods with optical measurement techniques. By substituting mechanical measurement systems with optical detection methods, the device achieves non-invasive real-time monitoring of microcirculatory flows while maintaining measurement precision through the sensitivity of optical detection to hemoglobin concentration changes.
3Measurement precision
If multiple wavelengths are used to estimate local metabolic parameters, then measurement precision is improved, but device complexity increases due to additional measurement channels
Solution Approach 1:
The patent utilizes parameter changes in light absorption characteristics of hemoglobin across different wavelengths to distinguish between oxyhemoglobin and deoxyhemoglobin. By measuring light absorption at multiple specific wavelengths where hemoglobin has distinct absorption properties, the device achieves precise estimation of local metabolic parameters (oxygen saturation, blood flow) while managing device complexity through selective wavelength choice based on known hemoglobin spectral characteristics.
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 real-time, non-invasive estimation of local metabolic parameters, providing better insights into tissue oxygenation and microcirculatory mechanisms, thereby enhancing patient care and treatment decisions.
Implementation Method 1
measured light intensities for the relevant tissue area, said light intensities being measured by an acquisition device for at least three different wavelengths of between 600 and 1000 nm, said wavelengths being selected as a function of the absorptivity of different types of hemoglobin
Data Source
AI summary
A method for estimating a local metabolic parameter of an area of tissue of a patient. The method receives light intensities from the area of tissue in question for at least three different wavelengths selected according to the absorptive power of different types of haemoglobin, on the basis of the absorbancy values calculated using the light intensities measured for the three wavelengths. The method determines a oxyhaemoglobin concentration and a deoxyhaemoglobin concentration and estimates at least one local metabolic parameter on the basis of the calculated oxyhaemoglobin and deoxyhaemo-globin concentrations.