Noninvasive Hematocrit Measurement via Optical Tissue Scattering
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Solution Overview
Problem
Current methods fail to provide a continuous, real-time detection of internal hemorrhage, especially when there are no external signs of trauma, as internal bleeding is difficult to detect due to autonomic compensatory changes, and existing technologies lack a noninvasive means to determine hematocrit in vivo.
Innovation Solution
A noninvasive method that irradiates tissue with a single incident wavelength and measures both wavelength-shifted and unshifted light emitted from the tissue, calculating hematocrit based on the relative volumes of light emitted from scattering and non-scattering phases associated with red blood cells and plasma.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional invasive methods are used to measure hematocrit, then measurement precision is improved, but ease of operation deteriorates and loss of time increases due to repeated sampling
Solution Approach 1:
The patent replaces mechanical/invasive sampling methods with optical measurement techniques. A probe emits light into tissue and detects scattered light properties, eliminating the need for needle punctures or blood draws. The optical system uses light scattering characteristics to noninvasively determine hematocrit values, making the measurement process as simple as placing a probe on the skin surface.
Solution Approach 2:
The patent introduces light as an intermediary substance to transfer information from the tissue to the detector. Light interacts with blood cells and plasma in the tissue, carrying information about hematocrit levels. The optical probe serves as an intermediary device that converts biological information into measurable optical signals without direct contact or invasion of the tissue.
2Reliability
If continuous monitoring is implemented, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent implements continuous hematocrit monitoring by maintaining constant optical illumination of the tissue and continuously detecting scattered light signals. The system provides real-time data streams rather than intermittent measurements, enabling continuous tracking of hematocrit changes. This allows for immediate detection of hemorrhage or other blood volume changes without interruption.
Solution Approach 2:
The patent enables the tissue itself to serve as the measurement medium. The natural optical properties of blood cells and plasma interact with the incident light, requiring no additional markers, dyes, or external substances. The body's own biological materials provide the measurement signal, eliminating the need for complex sample preparation or external reagents.
3Ease of operation
If noninvasive measurement is used, then ease of operation is improved, but measurement precision deteriorates
Solution Approach 1:
The patent measures multiple optical parameters simultaneously, including scattered light intensity, wavelength shifts, and temporal characteristics. By analyzing changes in these parameters rather than relying on a single measurement, the system achieves high precision noninvasive hematocrit determination. The multi-parameter approach compensates for variations in tissue composition and probe positioning.
Solution Approach 2:
The patent transitions from one-dimensional direct blood sampling to multi-dimensional optical measurement in tissue. Instead of measuring hematocrit in a single blood sample, the system measures light scattering properties across multiple dimensions including spatial distribution, wavelength spectrum, and temporal dynamics. This dimensional expansion enables precise noninvasive measurement through complex optical analysis.
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, real-time monitoring of hematocrit levels without invasive procedures, allowing for early detection of internal hemorrhage and monitoring of blood flow, applicable to various medical conditions.
Implementation Method 1
measuring wavelength shifted (IE) and unshifted (EE) light emitted from the tissue
Implementation Method 2
determining a relative volume of light emitted from two phases, wherein the two phases comprise a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells
Implementation Method 3
a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells
Data Source
AI summary
The invention provides a method and apparatus obtaining a hematocrit from a sample of in vivo tissue. The method comprises irradiating the sample with a single incident wavelength on a sample of tissue, simultaneously measuring wavelength shifted (IE) and unshifted (EE) light emitted from the tissue, and determining a relative volume of light emitted from two phases, wherein the two phases comprise a first Rayleigh and Mie scattering and fluorescent phase associated with red blood cells, and a second, non-scattering phase associated with plasma. The hematocrit is calculated from the volume of light emitted by the first phase relative to the total volume of light emitted from the first and second phases.