Non-invasive Lung Water Measurement via Thermal Sensing
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Solution Overview
Problem
Current methods for measuring Extravascular Lung Water (EVLW) are invasive, time-consuming, and cumbersome, limiting their clinical acceptance and effectiveness, especially in critically ill patients where rapid and non-invasive monitoring is crucial.
Innovation Solution
A non-invasive method and device that measures lung tissue thermal properties by analyzing the rate of temperature change of exhaled gas through controlled changes in inhaled gas parameters, such as temperature, humidity, or breathing patterns, allowing for the determination of EVLW volume within a short period of up to ten breathing cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive thermodilution techniques are used to measure EVLW, then measurement precision is improved, but device complexity and ease of operation deteriorate due to catheterization requirements
Solution Approach 1:
The patent replaces the mechanical invasive catheterization system with a non-invasive thermal sensing system. Instead of inserting catheters into blood vessels to measure temperature changes during thermodilution, the invention uses external thermal sensors to detect heat transfer through the chest wall to the lungs, thereby eliminating the need for invasive mechanical intervention while maintaining measurement capability
Solution Approach 2:
The patent introduces the chest wall and surrounding tissue as an intermediary medium between the external thermal sensor and the lung tissue. Rather than directly contacting the blood or lung tissue via catheter, the system measures thermal properties through this intermediate layer, allowing non-invasive access to EVLW information that was previously only obtainable through direct invasive contact
2Measurement precision
If traditional thermodilution methods are used, then measurement accuracy is improved, but loss of time increases due to procedure complexity
Solution Approach 1:
The patent extracts the essential measurement function from the complex invasive procedure. By isolating the thermal measurement aspect and removing the invasive catheterization steps, the system retains the core accuracy mechanism (thermal detection) while eliminating the time-consuming procedural elements such as catheter insertion, positioning, and connection
Solution Approach 2:
The patent enables the measurement system to function autonomously without requiring complex procedural steps. The external thermal sensor automatically detects thermal changes in real-time as they occur during normal breathing, eliminating the need for manual intervention, indicator injection, and complex data processing steps required by traditional thermodilution methods
3Reliability
If invasive catheterization is performed for EVLW measurement, then reliability of measurement is improved, but object-affected harmful factors increase due to procedural complications
Solution Approach 1:
The patent converts the harmful effect of invasive procedures into a beneficial non-invasive approach. Instead of accepting the inevitable complications of catheterization (infection, bleeding, vessel damage) as unavoidable trade-offs for reliable measurement, the invention uses external thermal sensing to achieve comparable measurement reliability without exposing the patient to these harmful effects, thereby converting the harm of invasiveness into the benefit of safety
4Ease of operation
If non-invasive thermal measurement is used, then ease of operation is improved, but measurement precision may deteriorate due to external measurement challenges
Solution Approach 1:
The patent applies local quality by focusing the thermal measurement on the specific region of interest (chest wall overlying the lungs) rather than attempting general body temperature measurement. The external thermal sensor is positioned to detect localized thermal changes at the chest wall that correspond to lung thermal properties, thereby maintaining precision despite the non-invasive external approach
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 provides a rapid, non-invasive, and reliable method for monitoring EVLW, reducing measurement time and avoiding complications associated with invasive procedures, while maintaining high accuracy and applicability in various clinical settings, including intensive care units and outpatient departments.
Implementation Method 1
heat exchange between the lungs and the environment
Implementation Method 2
heat exchange between the lungs and the environment
Implementation Method 3
having an inner heat source (pulmonary blood flow) and an outgoing heat stream
Data Source
AI summary
The subject matter discloses a noninvasive method and device for detection, measurement and monitoring of Pulmonary Interstitial fluid—Extravascular Lung Water —volumes in inpatient settings: Intensive Care Units, Emergency Rooms, Internal Hospital Departments, and daily monitoring of chronic patient in outpatient settings: outpatient departments, rehab centers and Home monitoring. The disclosed method is based on the analysis of lung tissue thermodynamic properties, and their deviation from normal value. The device measures the rate of temperature change of a lung tissue by measuring the exhaled gas temperature changing rate during cooling/heating of lung tissue. The cooling/heating of lung tissue may be achieved by prompt changing one of the inhaled gas parameters temperature, and/or humidity, and/or rate of breathing, and/or tidal volume, and/or type of gas and etc. The change is performed at the beginning of measurement, and is kept during entire measurement time.