Endogenous CO Breath Analyzer with Concentration Difference Fitting
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Solution Overview
Problem
Existing methods for measuring endogenous CO concentration in alveolar air face challenges such as insufficient gas sample volume, electrical level zero drift, residual CO in cleaning gas, and deviations due to ambient temperature and pressure changes, as well as inconsistent sampling and injection operations, which affect measurement accuracy.
Innovation Solution
The solution involves an apparatus using absorption spectroscopy with an open measuring chamber, incorporating a CO2 gas measuring chamber and a CO gas measuring chamber connected through a tracheal line, a processing unit for calculating concentration net values, and an injecting-sample-into-chamber system with a gas control unit and driving unit to manage gas sampling and injection, establishing a "concentration difference/electrical level difference" fitted standard curve to correct for measurement inaccuracies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-dispersive infrared spectroscopy or electrochemical methods are used to measure CO concentration, then measurement capability is achieved, but large amount of gas samples are required which are not suitable for human body breath measurement
Solution Approach 1:
The patent extracts and measures only the relevant CO concentration parameter from the breath sample using a specialized sensor system, rather than requiring large volumes for comprehensive analysis. The sensor selectively detects CO while the system extracts key physiological information with minimal gas consumption.
Solution Approach 2:
The patent replaces traditional mechanical gas handling systems with electronic sensing and signal processing. Instead of using large gas samples that require mechanical transport and handling, the system uses electronic sensors to detect CO concentration directly from small breath samples, substituting mechanical operations with electronic measurement.
2Quantity of substance
If gas chromatography is used to measure CO concentration with small sample amounts, then measurement accuracy for low CO concentration is satisfied, but operation and maintenance become complex and expensive
Solution Approach 1:
The patent employs disposable or easily replaceable sensing elements rather than complex, expensive gas chromatography systems. The sensor can be replaced without requiring complex calibration or maintenance procedures, making the system simpler and more cost-effective for routine clinical use.
Solution Approach 2:
The patent replaces the complex mechanical and chemical separation system of gas chromatography with a simpler electronic sensing system. This substitution eliminates the need for complex operation and maintenance while maintaining the ability to measure low CO concentrations accurately.
3Device complexity
If absorption spectroscopy with open measuring chamber is used, then device simplicity is achieved, but deviation occurs between measured CO concentration and actual exhaled alveolar air concentration due to ambient air mixing
Solution Approach 1:
The patent uses feedback mechanisms to detect and correct for ambient air mixing effects. The system continuously monitors the measurement conditions and adjusts the results based on detected deviations, compensating for the open chamber design's vulnerability to contamination without requiring a complex closed system.
Solution Approach 2:
The patent changes measurement parameters such as sampling timing, flow rate control, and chamber pressure to minimize ambient air mixing effects. By optimizing these parameters, the system achieves accurate measurements with a simple open chamber design, avoiding the need for complex sealed systems.
4Device complexity
If electrical level zero drift is not controlled, then measurement process remains simple, but measurement accuracy of low concentration CO deteriorates
Solution Approach 1:
The patent performs preliminary actions to prevent electrical level zero drift before measurements are taken. This includes pre-calibration, baseline establishment, and environmental conditioning of the sensor system. By preparing the system in advance, the need for complex real-time drift correction mechanisms is reduced.
Solution Approach 2:
The patent changes operational parameters such as temperature stabilization, humidity control, and sensor conditioning to minimize electrical level zero drift. By optimizing these parameters, the system maintains measurement accuracy for low CO concentrations without requiring complex active drift compensation systems.
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 reduces the required gas sample volume, improves measurement accuracy by accounting for electrical level zero drift and residual CO, and compensates for deviations caused by ambient conditions, providing a more accurate estimation of endogenous CO concentration in alveolar air.
Implementation Method 1
The apparatus for measuring an endogenous CO concentration in the alveolar air operates on a measuring principle of absorption spectroscopy with an open measuring chamber
Implementation Method 2
concentration of CO2 gas or concentration difference of CO2 gas (ΔCO2) in sample gas and base gas, as well as concentration of CO or concentration difference of CO gas (ΔCO) in the sample gas and the base gas are measured under a same temperature and pressure
Data Source
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AI summary
A method and apparatus for measuring endogenous CO concentration in alveolar air, comprising: 1. proposing a method for injecting samples in small amounts, multiple times, intermittently, and establishing a CO concentration relationship between sample gas and gas in a gas chamber after completion of sample injection; 2. establishing a "concentration difference/electrical level difference" difference value fitting method, to obtain a fitted standard curve for a difference value between the sample gas and base gas; 3. establishing an apparatus capable of measuring both CO and CO2, for measuring a CO concentration difference and a CO2 concentration difference between sample gas and base gas; 4. proposing a method for compensating a measurement value for endogenous CO in alveolar air. The problem that the amount of sample gas in a breath test is small, and cannot completely replace the gas originally inside the gas chamber, is solved through the adoption of the method for injecting samples in small amounts, multiple times, intermittently. The difference value fitting method effectively eliminates the effects of electrical level zero drift and residual CO of unknown concentration in cleaning gas. The compensating method can eliminate offsets caused by the temperature and pressure at the time of measurement being different from the temperature and pressure at the time of calibration or by air from the surroundings being mixed into sample gas.