Neonatal CO2 Sensor Pneumatic Sample Storage
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Solution Overview
Problem
Current capnometry systems face limitations in accurately measuring CO2 in fast breathing patterns due to sensor response time and gas mixing issues, particularly in neonatal applications where breathing rates exceed 30 breaths per minute, leading to signal clipping and inaccurate readings.
Innovation Solution
A pneumatic system that collects and stores end-tidal gas samples from multiple breaths, allowing the sensor sufficient time to register the full amplitude of CO2, while preventing gas mixing through precise valve control and isolation chambers, ensuring a homogeneous sample for measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard response time sensor is used for CO2 measurement, then the device complexity remains low, but the measurement precision deteriorates at fast breathing rates due to signal clipping
Solution Approach 1:
The system collects and stores breath samples in a sample collection chamber before analysis, preparing the sample in advance so that the sensor can measure it at a slower pace. This preliminary collection action allows the use of a standard response time sensor while achieving accurate measurements of fast breaths, as the breath rate division means the sensor only needs to process one breath every N cycles.
Solution Approach 2:
A sample collection chamber acts as an intermediary between the breath source and the sensor. This chamber temporarily holds the breath sample, allowing the system to decouple the fast breathing rate from the sensor's measurement rate. The chamber mediates the timing discrepancy between fast breath arrival and slower sensor response.
2Measurement precision
If gas sampling is performed continuously through tubing and valves, then the measurement can be performed, but gas mixing occurs that disturbs the homogeneity and purity of the breath sample
Solution Approach 1:
The system segments the breath measurement process into distinct phases: breath collection phase where samples are gathered in the chamber, and measurement phase where the sensor analyzes the collected sample. This segmentation allows the system to maintain sample purity during collection by isolating breaths in the chamber, then perform measurements without continuous gas flow that would cause mixing.
Solution Approach 2:
The system performs preliminary breath collection and storage in the sample collection chamber before the measurement occurs. This preliminary action separates the collection process from the measurement process, allowing the breath sample to be isolated and maintained in a pure state before analysis, avoiding the mixing that would occur with continuous sampling through tubing.
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 accurate and reliable CO2 measurement even at high breathing rates by extending the sample duration to match the sensor response time, reducing signal clipping and improving measurement fidelity, thus addressing the limitations of existing capnometry systems.
Implementation Method 1
Infra-Red sensors are used to measure the CO2 in the exhaled breath
Data Source
AI summary
A breath parameter measuring device is described which takes into account breathing patterns which historically have been incompatible with accurate measurements. In particular, during fast breathing patterns, the sensor performing the measurement may not be able to respond quickly enough to provide the true reading. The disclosure may be useful for example in the case of neonatal breath carbon dioxide measurements.