Physiological Measurement Calibration via Temperature Manipulation
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Solution Overview
Problem
Current non-invasive physiological measurement systems face challenges in accurately determining physiological parameters due to various variables such as differences in skin pigmentation, bone structure, operating temperatures, and changes in patient physiology, which require extensive testing and result in less precise measurements.
Innovation Solution
A robust calibration technique that isolates the effects of single variables, allowing for the generation of a calibration mapping that decouples physiological measurements from interfering factors, specifically using temperature manipulation to isolate perfusion index effects on total hemoglobin measurements, enabling more precise and less data-intensive calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple wavelength optical sensors are used to measure physiological parameters, then measurement capability is improved, but measurement precision deteriorates due to interference from variables such as skin pigmentation, bone structure, temperature, and perfusion changes
Solution Approach 1:
The calibration process is segmented into multiple distinct phases: initial calibration at a first temperature to establish baseline relationships, and subsequent calibration at a second temperature to capture temperature-dependent variations. This segmentation allows the system to isolate and calibrate for specific interfering factors (temperature, perfusion) separately, improving overall measurement precision by addressing each variable independently rather than attempting to account for all variables simultaneously
Solution Approach 2:
The system performs preliminary calibration actions at different temperatures and perfusion states before actual physiological measurements are taken. By pre-establishing calibration relationships under controlled varying conditions (temperature manipulation, perfusion index monitoring), the system prepares correction factors in advance that compensate for interfering variables during subsequent measurements, thereby improving measurement precision without requiring real-time adjustments
2Adaptability or versatility
If extensive testing is performed to account for various variables, then calibration coverage is improved, but calibration complexity and data requirements worsen
Solution Approach 1:
The invention extracts and isolates the effect of perfusion index as a separate calibratable variable. By monitoring perfusion index independently and incorporating it as a specific parameter in the calibration process, the system separates this interfering factor from the overall calibration complexity. This extraction allows the calibration to systematically account for perfusion variations without requiring exhaustive testing of all possible combinations of interfering variables, thereby reducing calibration complexity while maintaining comprehensive coverage
Solution Approach 2:
The system deliberately changes key parameters (temperature, perfusion index) during calibration to establish how measurements respond to these variations. By systematically varying temperature between at least two different values and monitoring corresponding changes in perfusion index and physiological measurements, the system creates a calibrated model that adapts to parameter changes. This approach provides broad calibration coverage across varying conditions without requiring exhaustive testing, as the calibrated relationships capture the essential behavior across the parameter space
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 results in more robust and accurate physiological measurements by minimizing the impact of related physiological changes, reducing the need for extensive data collection and real-time adjustments, and improving measurement precision, especially at extreme values.
Implementation Method 1
The tissue of the patient attenuates the light, which is then detected by a detector
Implementation Method 2
specifically using temperature manipulation to isolate perfusion index effects on total hemoglobin measurements
Data Source
AI summary
The present disclosure provides a calibration system and method for calibrating a physiological measurement based on a variable that affects the measurement. The variable can be a related physiological measurement. The technique can be implemented to obtain robust calibrations with minimal test data and computational effort.