Tracheostomy Tube Inner Cannula Telescopic Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing tracheostomy tube assemblies face issues with the removal and insertion of inner cannulas, which can cause leakage and require excessive force, due to the risk of the connector becoming unscrewed during ventilation, and the need for frequent removal of the outer tube to clean the inner cannula.
Innovation Solution
A tracheostomy tube assembly with a male connector that rotates relative to the hub, featuring cooperating screw threads and surface formations allowing the inner cannula to be easily inserted and removed by rotating the connector, ensuring secure attachment and minimizing force on delicate tissues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the inner cannula is made thin-walled and close-fit within the outer tube to provide a large bore, then the resistance to flow of gas is reduced, but the cannula becomes insufficiently stiff and requires excessive force for insertion and removal
Solution Approach 1:
The inner cannula is divided into multiple segments that can telescope relative to each other. During insertion, the segments collapse into a compact configuration, reducing the insertion force required. During removal, the segments expand to maintain structural integrity and reduce the force needed. This segmentation allows the cannula to remain thin-walled for low gas resistance while requiring minimal force for manipulation.
Solution Approach 2:
The inner cannula transitions from a static rigid structure to a dynamic telescopic structure that can change its configuration. The telescopic sections allow the cannula to adapt its shape and size during insertion and removal operations, reducing the force required while maintaining structural integrity when needed.
2Force
If the connector is screw-threaded onto the hub to reduce pulling and pushing force, then the force for inner cannula removal is reduced, but the connector may become unscrewed inadvertently causing leakage
Solution Approach 1:
A bayonet coupling mechanism serves as an intermediary between the connector and hub, providing both mechanical attachment and rotational engagement. The bayonet coupling includes a protrusion on the connector that engages with a recess in the hub, creating a positive mechanical lock that prevents inadvertent unscrewing while allowing controlled rotation for attachment and detachment.
Solution Approach 2:
The bayonet coupling features asymmetric geometry with a protrusion on the connector that fits into a specifically shaped recess in the hub. This asymmetric design creates a unique engagement orientation that prevents rotation in the wrong direction and ensures secure attachment, while still allowing controlled rotation in the correct direction for attachment and detachment.
3Ease of manufacture
If frequent removal of the outer tube is performed to clean the inner cannula, then the inner cannula can be cleaned effectively, but the procedure becomes time-consuming and disruptive to ventilation
Solution Approach 1:
The inner cannula is extracted as a separate, independently removable component from the outer tube assembly. The telescopic sections allow the inner cannula to be completely removed from the outer tube for cleaning while the outer tube remains in place, maintaining ventilation continuity. This extraction capability enables easy cleaning without disrupting the overall tracheostomy assembly or requiring removal of the outer tube.
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 allows for smooth and secure insertion and removal of the inner cannula, reducing the risk of leakage and discomfort, while maintaining the connector's attachment to the outer tube, facilitating easy cleaning and replacement without excessive force.
Implementation Method 1
The surface formations on the connector and the inner cannula preferably include cooperating screw threads. The connector is preferably rotatable by less than a full rotation, such as through an angle of about a quarter turn.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A tracheostomy tube assembly includes an outer tube (1) and an inner cannula (2) removably inserted in the outer tube. The connector (15) on the machine end of the outer tube is rotatable through about a quarter turn and has a screw thread (30) on its inner surface. The hub (33) on the machine end of the inner cannula (2) is also formed with a screw thread (35) arranged to engage with the screw thread (30) in the connector. The inner cannula (2) is pulled into the outer tube (1), or is pushed outwardly of the tube, by rotating the connector.