Remote Pressure Sensor Breath Sensing
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Solution Overview
Problem
Existing high flow respiratory therapy systems face challenges in accurately sensing and monitoring patient breathing due to the open nature of nasal cannula systems, which results in small pressure changes that are difficult to detect and can be obscured by gas turbulence and condensation.
Innovation Solution
A breath sensing device is provided, featuring a nasal cannula with a sensing lumen and a pressure sensor positioned remotely to detect pressure changes within the lumen. This configuration reduces signal noise and allows for accurate detection of breathing patterns, even at high flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a nasal cannula system is used for high flow respiratory therapy, then the patient can receive supplemental breathing gas at high flow rates, but the pressure changes become very small (5-50 Pa) and difficult to detect due to the open nature of the system
Solution Approach 1:
A sensing lumen acts as an intermediary element between the nasal cannula and the pressure sensor. This dedicated lumen provides a controlled pathway for pressure transmission, isolating the sensor from the turbulent high-flow gas stream while still capturing the pressure changes caused by patient breathing. The sensing lumen amplifies the pressure signal by providing a direct, low-impedance route for pressure waves to reach the sensor.
Solution Approach 2:
The nasal cannula system is segmented into separate functional components: the gas delivery pathway, the sensing lumen, and the pressure sensor. By separating the sensing function from the gas delivery function, the system can optimize each component independently - the sensing lumen is designed specifically for pressure transmission while the cannula delivers gas at high flow rates without interfering with the measurement capability.
2Measurement precision
If the pressure sensor is positioned close to the nares for direct measurement, then pressure changes can be detected, but gas turbulence and high flow rates obscure the signal
Solution Approach 1:
The sensing lumen serves as a protective intermediary that shields the pressure sensor from direct exposure to turbulent gas flow. Instead of placing the sensor in the chaotic high-velocity stream where it would be overwhelmed by turbulence, the lumen provides a controlled conduit that translates the pressure changes into measurable signals while filtering out the harmful turbulent components.
Solution Approach 2:
The system replaces direct mechanical contact between the sensor and turbulent gas flow with a pressure-transmission-based measurement approach. The sensing lumen converts the complex mechanical turbulence into pressure differential signals that can be measured electronically, substituting the noisy mechanical measurement with a cleaner electrical signal representation.
3Ease of operation
If humidified breathing gas is delivered through the nasal cannula, then patient comfort and medical needs are met, but condensation forms in the system and obscures pressure signals
Solution Approach 1:
The sensing lumen is extracted as a separate, dedicated pathway for pressure measurement, physically isolating the pressure sensor from the humidified gas stream. This separation allows condensation to form in the main gas delivery pathway without affecting the pressure sensing capability, as the sensing lumen provides a distinct route for pressure transmission that remains clear of condensate.
Solution Approach 2:
The sensing lumen acts as an intermediary that protects the pressure sensor from condensation while still transmitting pressure signals. By providing a dedicated pressure transmission pathway separate from the humidified gas flow, the system allows humidification to proceed for patient comfort without the condensation interfering with sensor measurement reliability.
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 solution enables accurate monitoring of patient breathing patterns and efficiency during high flow respiratory therapy, overcoming the limitations of open nasal cannula systems by providing clear and reliable pressure signals.
Implementation Method 1
A pressure sensor positioned remotely to detect pressure changes within the lumen
Data Source
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AI summary
Devices and methods are provided herein for sensing and monitoring of patient breathing during high flow respiratory therapy. A nasal cannula having a sensing lumen and remotely-located pressure sensor is provided herein for breath sensing that provides an accurate and clear signal while high flow rates of breathing gas are delivered from the nasal cannula. Condensation can be removed from the sensing lumen by applying a constant, pulsatile, or burst flow of purge gas. The breath sensing apparatus can be integrated in a respiratory system with a breathing gas source or can be packaged as a separate device capable of adapting to a variety of systems.