Nasal Pillow Plenum Sensing for Accurate Ventilation Pressure
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Solution Overview
Problem
Nasal pillows interfaces for non-invasive ventilation face challenges in integrating pressure sensing due to errors caused by increased flow velocity, making accurate pressure measurement difficult within their confined space.
Innovation Solution
The integration of a pressure sensing tube with a pressure sensing port positioned to communicate with a plenum between the venturi throat and nasal pillow, along with a controller to correct for expected errors using a correction factor indexed by the sensed pressure and jet nozzle flow, ensures accurate pressure measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pressure sensing is integrated into nasal pillows to minimize interface encumbrance, then patient comfort is improved, but measurement precision deteriorates due to increased flow velocity affecting pressure sensing accuracy
Solution Approach 1:
The patent introduces a plenum as an intermediary chamber between the jet nozzle and the pressure sensing port. This plenum acts as a buffer zone that decouples the high-velocity flow region from the pressure sensing region, allowing accurate pressure measurement while maintaining the compact nasal pillow design. The plenum mediates between the conflicting requirements of compactness and measurement accuracy.
Solution Approach 2:
The patent extracts the pressure sensing function from the direct flow path and relocates it to a separate plenum chamber. By taking the pressure sensing port out of the high-velocity jet region and placing it in the plenum where flow velocity is reduced, the system maintains compact nasal pillow dimensions while achieving accurate pressure measurements.
2Ease of operation
If a compact nasal pillow design is used to minimize interface encumbrance, then patient comfort is improved, but device complexity increases due to the challenging integration of reliable pressure sensing functionality
Solution Approach 1:
The patent merges the pressure sensing chamber (plenum) with the existing nasal pillow structure and jet nozzle assembly. By combining these functions into a single integrated unit where the plenum is formed as part of the nasal pillow body, the design achieves compactness without proportionally increasing device complexity. The merged structure eliminates the need for separate pressure sensing components.
Solution Approach 2:
The plenum serves multiple functions simultaneously: it acts as a flow distribution chamber, a pressure equalization chamber, and a housing for the pressure sensing port. This multi-functionality reduces the number of separate components needed, thereby integrating pressure sensing into the compact nasal pillow design without significantly increasing overall device complexity.
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 allows for precise pressure sensing within the nasal pillows, minimizing encumbrance and ensuring compliance with international standards while maintaining patient comfort.
Implementation Method 1
a throat body defining a venturi throat that is open to ambient air, a jet nozzle arranged to output ventilation gas into the venturi throat
Implementation Method 2
due to Bernoulli's principle, sensing pressure in a region where air is flowing is susceptible to error as flow velocity increases
Data Source
AI summary
A patient ventilation interface has a throat body defining a venturi throat that is open to ambient air, a nasal pillow disposed around the venturi throat to define a plenum between the venturi throat and the nasal pillow, a jet nozzle arranged to output ventilation gas into the venturi throat, and a pressure sensing tube having a pressure sensing port positioned to be in fluid communication with the plenum. The nasal pillow may be an integral part of the throat body. An expected error in the sensed patient airway pressure Psense may be corrected by applying a correction factor Pdelta indexed by the sensed patient airway pressure Psense and a jet nozzle flow V′n of the jet nozzle. Delivery of the ventilation gas output by the jet nozzle may be controlled in response to the corrected patient airway pressure.