Removable Cannula with Longitudinal Slot for Safe Catheter Puncture
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Solution Overview
Problem
Existing catheter systems pose risks of injury to patients and medical staff due to the difficulty in safely removing puncturing cannulas without damaging equipment, as current methods require significant strength and can result in protruding edges or catheter damage.
Innovation Solution
A catheter with a removable cannula featuring a tubular shape and a longitudinal slot extending 90° to 180° of its circumference, allowing the cannula to be secured within a tubular sheath for controlled movement and protection, enabling safe puncture and removal without exposing hazardous tips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cannula is provided with a rupture line for separation, then the cannula can be removed from the catheter, but separating the cannula requires a lot of strength and may cause formation of protruding edges and risk of injuries
Solution Approach 1:
The cannula is segmented into two parts: a puncturing cannula and a protective sheath. The sheath remains on the catheter after puncture while the cannula is removed through the longitudinal slot, eliminating the need for forceful separation and preventing edge formation.
Solution Approach 2:
The protective sheath acts as an intermediary that remains on the catheter after the cannula is removed. This sheath provides a safe interface for catheter connection and eliminates the need to directly handle or separate the cannula from the catheter, thereby preventing injury risks.
2Productivity
If the cannula tip is exposed for puncturing, then puncture function is enabled, but the tip poses inadvertent risk of injury for persons handling the cannula
Solution Approach 1:
The cannula dynamically transitions between two states: retracted within the protective sheath during handling and storage, and extended through the sheath during puncture. This dynamic configuration allows the tip to be exposed only when needed for puncturing while maintaining protection during other phases.
Solution Approach 2:
The puncturing cannula is nested within the protective sheath during storage and handling. The sheath contains the sharp tip, and the cannula can be extended from the sheath only when puncture is required, thereby protecting handlers from the sharp tip while maintaining puncture functionality.
3Productivity
If the catheter is guided in the cannula during puncture, then the puncture pathway is established, but the cannula cannot be removed via the connection end
Solution Approach 1:
The removal system is segmented into two independent components: the cannula that is removed through the longitudinal slot, and the protective sheath that remains on the catheter. This segmentation allows cannula removal without interfering with the catheter connection at the opposite end.
Solution Approach 2:
The cannula removal path is changed from the longitudinal axis (through the connection end) to a radial dimension (through the longitudinal slot in the cannula wall). This dimensional change allows removal without disassembling the catheter connection.
4Productivity
If the cannula is made rigid for effective puncturing, then puncture function is improved, but the cannula may damage the catheter during removal
Solution Approach 1:
The system is segmented into the rigid puncturing cannula and the flexible protective sheath. The sheath's flexibility compensates for the cannula's rigidity during removal, allowing the rigid cannula to be extracted through the slot without damaging the more fragile catheter.
Solution Approach 2:
The protective sheath serves as an intermediary that absorbs mechanical stresses during cannula removal. The sheath remains on the catheter and provides a flexible interface that prevents direct contact between the rigid cannula and the catheter wall during the extraction process.
Data Source
Figure 1a
Figure 1b
Figure 1c
AI summary
The aim of the present invention is to provide a catheter with a puncturing cannula which may be removed from the catheter without risk of injury for the patient and the nursing staff nor risk of damaging the equipment, and whose tip is protected before as well as after puncturing the body cavity. According to the invention, this object is satisfied by a catheter with removable cannula (1) for puncturing a body cavity, whereas the catheter can be moved freely in the longitudinal direction in the cannula (1). The cannula is characterised in that it is tubular in shape and provided with a longitudinal slot (10) extending over 45° to 180° of the circumference of the cannula (1) and in that it is provided in a tubular sheath (2) so that they can be displaced in the longitudinal direction inside said tubular sheath (2).