Portable Metabolic Analyzer Adaptive Sampling

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Solution Overview

Problem

Current portable metabolic analyzer systems are limited by their bulkiness, high cost, and operator dependency, making them unsuitable for real-world applications, and they struggle to accurately measure resting energy expenditure (REE) and physical activity-related energy expenditure (PAE) due to issues with breath sample collection, flow rate measurement, and water condensation, while calorie intake tracking relies on tedious self-reporting methods.

Innovation Solution

The system employs an adaptive sampling mechanism for accurate breath sample collection, optimized flow rate measurement design, humidity regulation, and voice recognition for calorie intake tracking, along with algorithms to determine REE and PAE, and recommends physical activity based on measured REE to achieve target weight.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional indirect calorimetry equipment is used to measure REE, then measurement accuracy is improved, but device portability and ease of operation deteriorate

Engineering Contradiction:
ImproveREE measurement accuracyVSAvoidDevice portability and operation simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system divides the measurement process into distinct phases: calibration phase where flow rate constants are determined, and measurement phase where REE is calculated. This segmentation allows the device to be simple and portable while maintaining accuracy through structured procedural steps.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transforms the complex multi-parameter indirect calorimetry measurement into a simplified process by pre-determining flow rate constants during calibration. During actual measurement, only oxygen concentration and breath volume need to be measured, significantly reducing operational complexity while preserving measurement accuracy.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If portable versions of indirect calorimetry devices are used, then device portability is improved, but measurement accuracy and operator independence deteriorate

Engineering Contradiction:
ImproveDevice portabilityVSAvoidREE measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system performs preliminary calibration to determine flow rate constants before actual REE measurement. This preliminary action embeds device-specific characteristics into the measurement algorithm, enabling portable devices to achieve accurate measurements without requiring operator expertise in device calibration and operation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses measured oxygen concentration and breath volume data with pre-determined flow rate constants to calculate REE. This feedback mechanism ensures measurement accuracy is maintained in portable devices by continuously referencing calibrated parameters throughout the measurement process.

Inventive Principle:
Principle #23Feedback

3Device complexity

If self-reporting methods are used to track calorie intake, then device complexity is reduced, but tracking accuracy and reliability deteriorate

Engineering Contradiction:
ImproveSystem simplicityVSAvoidCalorie intake tracking accuracy
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system integrates multiple functions into a single platform: REE measurement through indirect calorimetry, PAE tracking through physical sensors, and calorie intake tracking through speech recognition. This multi-functionality creates a comprehensive energy balance system that compensates for individual method limitations through integration.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system introduces speech recognition technology as an intermediary between the user and calorie intake tracking. This intermediary automatically converts verbal food descriptions into quantified calorie data, maintaining system simplicity while significantly improving tracking accuracy and reliability compared to traditional self-reporting.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Extent of automation

If physical sensors are used to track PAE, then automation level is improved, but measurement coverage and accuracy deteriorate

Engineering Contradiction:
ImprovePAE tracking automationVSAvoidPhysical activity detection coverage
Core Design Contradiction:
Extent of automationVSAdaptability or versatility

Solution Approach 1:

The system merges multiple PAE tracking approaches: automated physical sensor detection for objective activities, speech recognition for subjective activity reporting, and REE measurement for metabolic context. This combination compensates for the limited coverage of individual sensors while maintaining high automation levels.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system creates a universal PAE tracking capability by integrating multiple detection methods. Physical sensors cover automated detectable activities, speech recognition covers activities beyond sensor detection, and together they provide comprehensive activity coverage with high automation through algorithmic integration of all data sources.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 significantly improves the accuracy and user-friendliness of REE measurement, reduces measurement time, and allows for integrated tracking of energy expenditure and calorie intake, enabling individuals to maintain a healthy energy balance without professional guidance.

Implementation Method 1

a flow sensor that measures a pressure difference between a first pressure and a second pressure

Methodology Applied
Scientific EffectPressure difference measurement: Pressure Drop

Implementation Method 2

an optical sensor that measures an optical property of the breath sample that correlates to an oxygen concentration in the breath sample

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 3

the optical property of the breath sample that correlates to a carbon dioxide concentration in the breath sample

Methodology Applied
Scientific EffectOptical absorption: Absorption (EM radiation)

Implementation Method 4

a thermistor located near the orifice that measures a temperature of the breath at the orifice

Methodology Applied
Scientific EffectElectrical resistance temperature dependence: Thermistor

Data Source

PatentEP2948046B1Portable metabolic analyzer system
Publication Date: 2019.05.15 THE ARIZONA BOARD OF REGENTS ON BEHALF OF THE UNIV OF ARIZONA
  • EP2948046B1 patent drawingFigure 1A~1C
  • EP2948046B1 patent drawingFigure 2
  • EP2948046B1 patent drawingFigure 3

AI summary

A system for measuring and tracking metabolic rate, physical activity and calorie intake. The metabolic rate is measured with a design that features an adaptive sampling mechanism for accurate breath sample collection, optimized flow rate measurement for minimizing backpressure while maximizing accuracy, humidity regulation and water condensation reduction mechanism for reliable performance, as well as breath temperature measurement for volume and humidity corrections. The system further comprises an improved algorithm for determining physical activity such as related energy expenditure, and a mechanism for tracking changes in food intake over time.