Tributary Venous Access Device with Bidirectional Valve
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Solution Overview
Problem
Current vascular access methods for hemodialysis, such as AV fistulas, grafts, and central venous catheters, suffer from complications like stenosis, thrombosis, infection, and systemic inflammation, leading to inadequate blood flow and high maintenance costs, with a need for a device that provides continuous access with minimal inflammation and reliable blood flow rates of 250 to 400 mL/min without complications.
Innovation Solution
A Tributary Venous Access (TVA) device with a two-way valve built into the tip, allowing flow in either direction with low opening and closing pressures, is placed through a tributary vein near a larger target vein, using a subcutaneous cuff for fixation and an anticoagulant lock solution to prevent clotting, and features a bidirectional valve that maintains lock solution concentration and prevents blood entry when not in use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a central venous catheter is placed into a central vein for hemodialysis, then blood access is provided, but fibrous sheathing develops around the catheter tip causing stenosis and reduced blood flow
Solution Approach 1:
The catheter tip is extracted from the central vein and placed in a tributary vein instead. This removes the source of irritation from the central vein wall, preventing sheathing and stenosis while maintaining blood access functionality.
Solution Approach 2:
A tributary vein serves as an intermediary structure between the catheter and the central vein. The catheter interacts with the tributary vein wall instead of the central vein wall, reducing direct irritation and inflammatory response.
2Stability of the object's composition
If a long catheter segment is placed within the vein to prevent tip exit, then catheter stability is improved, but venous irritation and sheathing increase
Solution Approach 1:
The catheter tip is extracted from the central vein environment and placed in a tributary vein, removing it from the harmful central vein wall contact zone while maintaining stability through proper positioning.
Solution Approach 2:
Different segments of the catheter have different functions: the body remains stable in the tributary vein while only the minimal necessary portion contacts the vein wall, reducing overall inflammatory response.
3Reliability
If anticoagulant lock solution is injected into the catheter, then clotting is prevented, but the solution concentration decreases due to parabolic flow and washing out
Solution Approach 1:
The catheter tip is extracted from the high-flow central vein region and placed in a tributary vein with lower flow velocity. This reduces the washing out effect and maintains higher anticoagulant solution concentration at the catheter tip.
Solution Approach 2:
The catheter design allows the anticoagulant solution to maintain itself through the two-way valve mechanism, which prevents blood contamination and maintains solution integrity without requiring frequent replenishment.
4Quantity of substance
If a two-way valve is added to prevent blood entry and maintain lock solution, then anticoagulant concentration is maintained, but device complexity increases
Solution Approach 1:
The two-way valve operates passively using the pressure differential between blood flow and lock solution. It automatically opens to allow lock solution injection and closes to prevent blood entry, requiring no external control or power source.
Solution Approach 2:
The valve utilizes hydraulic pressure principles to control blood flow direction. The valve opens when injection pressure exceeds blood pressure and closes when injection stops, using pressure differential to regulate flow automatically.
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 TVA device reduces systemic inflammation, minimizes fibrous sheathing and stenosis, maintains anticoagulant solution concentration, and ensures reliable blood flow, potentially lowering maintenance costs and improving patient outcomes by providing continuous access with minimal complications.
Implementation Method 1
A bidirectional valve is at the internal end of the catheter. The valve opens and closes in response to pressure differentials
Implementation Method 2
an anticoagulant lock solution to prevent clotting
Data Source
AI summary
Described herein are devices and methods for vascular access via the tributaries. A single lumen catheter, with a bidirectional valve at the tip is disclosed. Flow is out the longitudinal tip of the catheter and not the sides. The two-way valve will act passively but has low opening and closing pressures. A method utilizing endo-to-side port placement of said catheter in vasculature is disclosed. Anastomosis methods are described using said catheter.