Low Back Pressure Mouthpiece for Exhaled NO Detection
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Solution Overview
Problem
Current methods for measuring exhaled nitric oxide (NO) from the lower respiratory tract face challenges due to nasal NO contamination and require high back pressure, making it difficult for individuals with limited lung expiratory force, especially children, to maintain constant exhalation flow for accurate measurements.
Innovation Solution
A low back pressure mouthpiece is designed with a conduit and an oxidizing filter system that produces a back pressure of less than 4 cm H2O, allowing for accurate detection of exhaled NO by conditioning the breath and minimizing nasal contamination, featuring a breath inlet conduit, oxidizing filter housing, and filtering particles to facilitate stable NO measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high back pressure (5-20 cm H2O) is applied to prevent nasal NO contamination, then measurement accuracy is improved, but ease of operation deteriorates making it difficult for subjects with limited lung expiratory force
Solution Approach 1:
A low-resistance valve is introduced as an intermediary component in the breathing circuit that selectively allows exhaled air to pass through while maintaining back pressure to prevent nasal contamination. The valve creates a preferential flow path that reduces the effort required for exhalation while still achieving the necessary pressure to exclude nasal NO from the measurement
Solution Approach 2:
The system changes the pressure parameter by maintaining a lower back pressure (less than 4 cm H2O) compared to conventional systems (5-20 cm H2O). This parameter change is achieved through the low-resistance valve design that maintains adequate pressure to prevent nasal contamination while reducing the expiratory force required from the subject
2Measurement precision
If high back pressure (10-20 cm H2O) is required for measurement, then nasal NO contamination is reduced, but measurement duration increases making it difficult to maintain constant exhalation flow
Solution Approach 1:
The low-resistance valve acts as a mediator that reduces the time required for exhalation by providing a low-resistance flow path. This allows subjects to achieve the necessary exhalation flow more quickly and maintain constant flow for the required measurement duration without excessive total exhalation time
3Measurement precision
If conventional mouthpiece design is used, then nasal NO contamination occurs, but device complexity remains low
Solution Approach 1:
A low-resistance valve is introduced as an intermediary component in the breathing circuit that selectively allows exhaled air to pass through while maintaining back pressure to prevent nasal contamination. The valve creates a preferential flow path that reduces the effort required for exhalation while still achieving the necessary pressure to exclude nasal NO from the measurement
Solution Approach 2:
An oxidizing filter is incorporated into the mouthpiece design that uses porous material to condition the breath sample. The filter removes contaminants and prepares the sample for accurate NO measurement while adding minimal resistance to the breathing circuit
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
The low back pressure mouthpiece effectively conditions exhaled breath, achieving accurate NO measurements with reduced nasal contamination and lower pressure requirements, enabling reliable data collection even for subjects with limited lung capacity, including children, while maintaining a stable NO plateau at the end of exhalation.
Implementation Method 1
an oxidizing filter means coupled to the conduit means for sample conditioning
Data Source
AI summary
A low back pressure mouthpiece for accurate detection of exhaled nitric oxide (NO) includes a conduit for receiving the exhaled breath from the subject. An oxidizing filter for sample conditioning, wherein the conduit and oxidizing filter operate to produce a back pressure of less than 4 cm H2O; and a device for measuring the level of one or more components of the received exhaled breath.