Metabolic Analysis Device with Bypass Calibration
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Solution Overview
Problem
Existing devices for measuring oxygen consumption and carbon dioxide production in subjects, especially in clinical settings, face challenges with long warm-up times, complexity, and hygiene concerns during calibration, particularly when dealing with patients undergoing assisted pulmonary ventilation.
Innovation Solution
A portable device with automatic self-calibration capabilities, reduced dimensions, and semi-automatic calibration of a disposable flowmeter, allowing for quick and hygienic measurements by selectively routing air flows through a mixing mini-chamber or bypass line, using sensors for oxygen and carbon dioxide concentration, and an electronic control unit for processing signals to calculate metabolism metrics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a mixing chamber is used to accumulate air sampling flows over multiple respiratory cycles, then average measurements of oxygen consumption and carbon dioxide production can be obtained, but the device dimensions and portability are worsened
Solution Approach 1:
The mixing chamber is integrated within the compact housing of the device, with sensors and flow meters nested along the air sampling path. The mixing chamber utilizes the available internal volume efficiently by positioning it upstream of the sensors, allowing multiple respiratory cycles to be mixed within a minimized overall device footprint.
Solution Approach 2:
The device transitions from traditional large-scale metabolic carts to a portable configuration by reconfiguring the spatial arrangement of components. The mixing chamber, sensors, and flow meters are arranged in a compact linear sequence along the air sampling path, enabling portable deployment while preserving the mixing function across multiple respiratory cycles.
2Measurement precision
If manual calibration with calibration syringes is performed, then sensor accuracy can be maintained, but hygiene concerns arise when dealing with patients undergoing assisted pulmonary ventilation
Solution Approach 1:
The device employs disposable flow meters that are pre-calibrated and sealed in sterile packaging. These single-use components eliminate the need for manual calibration with calibration syringes, ensuring hygiene when dealing with patients undergoing assisted pulmonary ventilation. The disposable nature guarantees sterility while maintaining measurement accuracy through factory calibration.
Solution Approach 2:
The device incorporates automatic self-calibration capabilities through integrated sensors and electronic control units that perform routine calibration procedures without requiring manual intervention with calibration syringes. This self-service calibration system maintains sensor accuracy while eliminating hygiene risks associated with manual calibration procedures.
3Loss of information
If traditional metabolic measurement devices are used, then comprehensive metabolic data can be collected, but the devices are complex and not easily portable
Solution Approach 1:
The device integrates multiple functions into a single portable unit: oxygen and carbon dioxide sensors, flow meter, mixing chamber, and electronic control unit all work together to provide comprehensive metabolic measurements. The electronic control unit processes signals from all sensors to calculate oxygen consumption and carbon dioxide production, maintaining data completeness while reducing overall device complexity through functional integration.
Solution Approach 2:
The device combines the mixing chamber, oxygen sensor, carbon dioxide sensor, and flow meter into a single integrated portable unit. The electronic control unit merges the processing of signals from all these components, allowing comprehensive metabolic data collection in a compact form factor that is easily portable while maintaining measurement completeness.
4Measurement precision
If sensors are placed downstream of the mixing chamber, then accurate average measurements can be obtained, but the device requires long warm-up times prior to measurement
Solution Approach 1:
The device performs automatic self-calibration and sensor warm-up procedures automatically upon activation, before the actual measurement begins. The electronic control unit initiates calibration sequences that prepare the sensors and mixing chamber in advance, eliminating the need for manual warm-up time and allowing immediate accurate measurements of oxygen consumption and carbon dioxide production.
Solution Approach 2:
The device incorporates automatic self-calibration and self-warmup capabilities through the electronic control unit, which automatically prepares the sensors and mixing chamber for measurement upon activation. This self-service functionality eliminates long manual warm-up times while ensuring accurate average measurements are obtained from the downstream sensors.
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 efficient, rapid, and hygienic measurement of basal metabolism in both spontaneous and ventilated patients, reducing warm-up times and eliminating the need for calibration syringes, while maintaining precision and portability.
Implementation Method 1
first sensor means for sensing the oxygen concentration
Implementation Method 2
second sensor means for sensing the carbon dioxide concentration
Implementation Method 3
a suction pump having a substantially constant flow rate, said pump being arranged downstream of the main line, for drawing said sampling air flow into the main line
Data Source
AI summary
A device and a method for the analysis of the air exhaled by a subject in order to measure basal metabolism of the subject comprise a main line for a sampling flow of the air exhaled by a subject who breathes spontaneously or a subject undergoing assisted pulmonary ventilation. A mixing mini-chamber is provided for mixing a plurality of air sampling flows exhaled by the subject within a number of respiratory cycles. Sensors for sensing the oxygen concentration and the carbon dioxide concentration respectively measure the oxygen concentration and the carbon dioxide concentration within the air flow in the main line. The device further comprises an electronic control unit which processes signals from the sensors for obtaining a measurement of metabolism of the subject within a number of respiratory cycles. The electronic control unit is further programmed for automatically starting, upon switching on the device, a self-calibration stage of the device, by connecting the main line to a calibration line while causing the calibration flow to pass through a by-pass line by-passing the mixing mini-chamber, so that the calibration can be performed immediately, without requiring a filling of the mixing mini-chamber.