Bifurcated Nasal Cannula With Smooth Separate Gas Paths
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Solution Overview
Problem
Existing nasal cannulas suffer from high flow resistance, discomfort due to rigid connecting ribs, and condensation issues leading to rainout, which can be uncomfortable and dangerous for patients undergoing respiratory therapy.
Innovation Solution
A bifurcated nasal cannula design using three mandrels for dip molding, creating a custom bridge with smooth bore gas paths and separate lumens, allowing for low flow resistance, patient comfort, and integration of medicament delivery without mixing breathing gas and medicament flows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a connecting rib is used to join the two nasal prongs, then the structural integrity is improved, but the gas flow resistance increases and causes eddies
Solution Approach 1:
The patent removes the connecting rib structure that was previously used to join the two nasal prongs. By extracting this problematic component, the design eliminates the sharp corners and eddies that caused high flow resistance, while maintaining structural integrity through alternative means such as the cannula tubing configuration and support elements.
2Stability of the object's composition
If rigid material is used for the bridge spanning the space between prongs, then the structural stability is improved, but patient comfort deteriorates due to discomfort on the upper lip
Solution Approach 1:
The patent applies different material properties to different parts of the device. The bridge portion that contacts the patient's upper lip is made from soft, flexible material to ensure comfort, while other structural components can use more rigid materials for stability. This local differentiation of material quality resolves the contradiction between structural stability and patient comfort.
3Ease of manufacture
If the nasal prongs are closely located during dip molding, then the manufacturing simplicity is improved, but the gas path geometry becomes odd-shaped with large empty volume causing condensation
Solution Approach 1:
The patent uses preliminary action by positioning support elements or spacers between the nasal prongs during the dip molding process. These temporary structures prevent the formation of large empty volumes and odd-shaped gas paths, ensuring proper geometry is created during manufacturing. After molding, these support elements are removed, leaving the desired gas path configuration.
4Ease of manufacture
If steps or uneven surfaces are present in the gas flow path, then the manufacturing ease is improved, but moisture trapping increases causing larger condensation droplets
Solution Approach 1:
The patent employs curved, smooth transitions in the gas flow path geometry instead of sharp corners or uneven surfaces. By using rounded contours and gradual transitions, the design eliminates moisture trapping zones while maintaining ease of manufacture through the dip molding process, which naturally produces smooth curved surfaces.
Data Source
AI summary
Devices and methods for providing respiratory therapy are disclosed. One device includes a first lumen, a second lumen, and a bridge with at least one opening. The first lumen has a first inlet end to receive a first flow of breathing gas, a first outlet end to deliver the first flow, and a first bend between the first inlet end and the first outlet end. The second lumen has a second inlet end to receive a second flow of breathing gas, a second outlet end to deliver the second flow, and a second bend between the second inlet end and the second outlet end. The bridge separates the first lumen and the second lumen, attaches to the first lumen at the first bend and the second lumen at the second bend, and is configured to maintain the first flow of breathing gas separate from the second flow of breathing gas.