Implantable Infusion Device Dual Flow Path MRI Safety
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Solution Overview
Problem
Existing implantable infusion devices are not MRI-safe when delivering high infusion rates, as magnetic fields can cause unpredictable valve openings, leading to unsafe therapeutic agent delivery.
Innovation Solution
The development of implantable infusion devices with two flow paths, including a programmable pump for variable flow rates and a safety valve system that prevents unintended fluid delivery during MRI procedures, using MRI-safe valves and a flow restrictor to manage fluid flow safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a valve is used to control therapeutic agent delivery in a device capable of high infusion rates, then the device can deliver bolus infusions exceeding 1 milliliter per minute, but the magnetic field during MRI procedures may cause unpredictable opening or closing of the valve, resulting in unsafe therapeutic agent delivery
Solution Approach 1:
The device is divided into two separate flow paths: a first flow path with a programmable pump for controlled delivery, and a second flow path with a flow restrictor for high-rate bolus delivery. This segmentation isolates the high-rate capability from the controlled delivery mechanism, allowing the pump to maintain reliability during MRI while the restrictor provides safe bolus capability when activated.
Solution Approach 2:
A safety valve is introduced as an intermediary component in the second flow path that acts as a fail-safe mechanism. This safety valve is designed to remain closed during MRI procedures regardless of magnetic field interference, preventing unintended high-rate delivery while allowing controlled activation under normal operating conditions.
2Measurement precision
If a programmable pump mechanism is used to provide variable flow rates, then the device can deliver precise amounts of therapeutic agent over time, but the device cannot achieve high bolus infusion rates of 1 milliliter or more per minute
Solution Approach 1:
The device separates the flow control function into two distinct paths: the first flow path with a programmable pump for precise low-rate delivery, and the second flow path with a flow restrictor for high-rate bolus delivery. This allows each path to be optimized for its specific function without compromise.
Solution Approach 2:
The device integrates multiple delivery capabilities into a single system that can switch between precise programmable delivery and high-rate bolus delivery depending on therapeutic needs, making the device universally applicable for both maintenance dosing and rescue dosing scenarios.
3Adaptability or versatility
If the device allows fluid delivery via multiple flow paths to achieve both programmable and high-rate delivery, then the device can meet diverse therapeutic needs, but the complexity of controlling which path allows fluid exit increases
Solution Approach 1:
The safety valve in the second flow path is designed to be inherently stable during MRI procedures, automatically preventing high-rate delivery without requiring active control or monitoring during the procedure. This self-protecting mechanism reduces the control burden on the system.
Solution Approach 2:
The flow restrictor is pre-configured in the second flow path to limit maximum delivery rate, and the safety valve is pre-positioned to control access to this path. These preliminary configurations ensure that even if activation occurs, the delivery remains within safe parameters, reducing the need for complex real-time control.
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 devices ensure safe and controlled delivery of therapeutic agents, preventing unintended fluid release during MRI procedures by employing stable valves and a safety valve mechanism, thus maintaining MRI safety while allowing for high infusion rates.
Implementation Method 1
One or more active MRI-safe valves, such as piezoelectric valves, may be employed upstream or downstream of the restrictor or pump to control whether fluid exits the outlet via the first or second flow path.
Data Source
AI summary
An implantable infusion device includes a positive pressure reservoir, a pump, a flow restrictor, and an outlet. The device includes a first fluid flow path from the reservoir to the outlet, where the pump is downstream of the reservoir, and the outlet is downstream of the pump. The device further includes a second fluid flow path from the reservoir to the outlet, where the flow restrictor is downstream of the reservoir, and the outlet is downstream of the restrictor. The device may also include one or more controllable, MRI-safe valves to select whether fluid is delivered via the first or second flow path.