Cartridge Connector with Exhaust Needle for pH-Stable Buffer Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The pH of sodium bicarbonate solutions used in medical applications is not fixed due to CO2 equilibrium issues, leading to unpredictable pH changes when drawn from vials with headspace, making it difficult to buffer anesthetics effectively and safely.
Innovation Solution
A dosing pen system with a cartridge connector that allows for controlled transfer of buffer solutions from a buffer cartridge to an anesthetic cartridge, featuring a transfer needle and an exhaust needle, where the transfer needle is removed from the buffer cartridge before removing the anesthetic cartridge, ensuring the buffer remains sealed and pH stability, and enabling variable volume selection and reuse of components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bicarbonate solution is drawn from a vial with headspace, then the solution can be transferred to a syringe or cartridge, but the pH becomes unpredictable due to CO2 evolution
Solution Approach 1:
The invention extracts the headspace (containing CO2 gas) from the bicarbonate solution container before transfer. By removing the headspace portion of the solution that has been in contact with CO2, the system prevents CO2 from evolving into the solution during transfer, thereby maintaining predictable pH levels in the transferred bicarbonate solution.
Solution Approach 2:
The invention performs preliminary action by pre-removing the headspace from the bicarbonate solution container before the actual solution transfer. This preliminary removal of CO2-containing headspace prevents subsequent pH changes during the transfer process, ensuring pH stability is maintained throughout the operation.
2Productivity
If a single buffer cartridge is used to buffer multiple anesthetic cartridges, then efficiency increases, but the buffer pH may change unpredictably between uses
Solution Approach 1:
The invention extracts the headspace from the buffer cartridge before each use. By removing the CO2-containing headspace portion of the buffer solution, the system ensures that the buffer maintains consistent pH levels across multiple uses, enabling reliable multi-cartridge buffering without pH drift.
Solution Approach 2:
The invention performs preliminary removal of headspace from the buffer cartridge before each buffering operation. This preliminary action prevents CO2 evolution during the buffering process, ensuring that the buffer pH remains consistent and predictable across multiple anesthetic cartridge bufferings.
3Device complexity
If bicarbonate solution is stored in a closed container with headspace, then the container design is simple, but CO2 can evolve and change the pH over time
Solution Approach 1:
The invention extracts the problematic headspace containing CO2 gas from the closed container. By removing this headspace portion before use, the system eliminates the source of CO2 that would otherwise evolve into the bicarbonate solution and cause pH changes, thereby maintaining composition stability.
Solution Approach 2:
The invention performs preliminary removal of the CO2-containing headspace from the closed container before the bicarbonate solution is used. This preliminary action prevents subsequent pH changes that would occur during storage or use, ensuring composition stability without requiring complex container designs.
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 system provides predictable and stable pH buffering for anesthetics, allowing for precise dosing and extended use of buffer cartridges, reducing the risk of pH-induced precipitation and enabling multiple anesthetic cartridges to be buffered from a single buffer source.
Implementation Method 1
a transfer needle which is part of the cartridge connector penetrates the septum of the buffer cartridge to establish a flow path out of the cartridge
Implementation Method 2
bicarbonate ions are in equilibrium as represented by the following expression: 2HCO3−CO2↑+CO32−+H2O
Implementation Method 3
carbon dioxide gas will continue to leave solution until the reaction has proceeded almost completely to the right
Data Source
AI summary
A system for transferring solutions from a first cartridge into a second cartridge comprises a cartridge holder, a plunger driver, and a cartridge connector. The cartridge connector carries a transfer needle and an exhaust needle. The cartridge holder positions the first cartridge against the cartridge connector so that the transfer needle penetrates the first cartridge septum. The second cartridge is removably inserted into another end of the cartridge connector so that both the transfer needle and the exhaust needle penetrate the second cartridge septum. The plunger driver is disposed to advance a plunger on the first cartridge to transfer solution from the first cartridge into the second cartridge thus displacing solution from the second cartridge through the exhaust needle. The cartridge connector includes a sealed interior waste chamber for receiving the solution from the second cartridge.