Flow-Restriction Extension Set for Low-Hemolysis Blood Draw
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Solution Overview
Problem
Existing blood draw systems using peripheral intravenous catheters (PIVCs) face challenges with hemolysis due to high shear stress on red blood cells, leading to compromised blood sample quality and potential vein or catheter collapse, along with blood spillage.
Innovation Solution
A flow restriction device with a micro-sized channel, typically 0.02 inches in diameter and 1.3 inches long, is integrated into the PIVC system to regulate blood flow, reducing shear stress and minimizing hemolysis by distributing pressure differentials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a vacuum blood collection container is coupled to the catheter for blood withdrawal, then blood collection efficiency is improved, but hemolysis of red blood cells occurs due to high shear stress from pressure differential
Solution Approach 1:
An extension tube assembly is introduced as an intermediary component between the catheter and the vacuum blood collection container. This extension tube has a smaller internal diameter than the catheter, which creates flow resistance and reduces the shear stress exerted on red blood cells during blood withdrawal, thereby preventing hemolysis while still allowing efficient blood collection.
2Speed
If a vacuum blood collection container is used, then blood draw speed is improved, but catheter tip collapse or vein collapse occurs due to high initial pressure differential
Solution Approach 1:
The extension tube assembly serves as a mediator that distributes the pressure differential along its length. The smaller diameter of the extension tube creates back pressure that gradually reduces the pressure gradient, preventing sudden collapse of the catheter tip or vein while maintaining adequate blood draw speed.
3Loss of time
If high vacuum pressure is applied for rapid blood collection, then collection time is reduced, but blood spillage increases due to loss of control
Solution Approach 1:
The extension tube assembly acts as a flow control intermediary that regulates blood flow from the catheter to the collection container. The restricted diameter of the extension tube creates resistance that controls the rate of blood flow, preventing excessive flow that would lead to spillage while maintaining efficient collection speed.
4Ease of operation
If a standard diameter catheter is used for blood withdrawal, then ease of insertion is maintained, but shear stress on red blood cells increases due to rapid flow
Solution Approach 1:
The blood withdrawal system is segmented into two distinct components with different diameters: the catheter (larger diameter for easy insertion) and the extension tube (smaller diameter for shear stress reduction). This segmentation allows each component to optimize its function - the catheter prioritizes ease of insertion while the extension tube prioritizes reducing shear stress on red blood cells.
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 flow restriction device effectively reduces hemolysis and blood wastage by controlling blood flow rate, maintaining blood sample integrity and compatibility with existing PIVC systems without requiring operational changes.
Implementation Method 1
The flow restriction device includes a tube with a small internal diameter (e.g., 0.02 inches or 0.508 millimeters) that creates flow resistance to reduce the shear stress exerted on red blood cells during blood withdrawal
Implementation Method 2
When the blood collection container is coupled to the catheter, a pressure in the vein is higher than a pressure in the blood collection container, which pushes blood into the blood collection container
Data Source
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AI summary
A flow restriction device may include a male luer connector portion, a female luer connector portion, and a flexible tube. The male luer connector portion defies a first lumen. The female luer connector portion defines a second lumen. The flexible tube defines a third lumen. The third lumen is in fluid communication with the first lumen and the second lumen. The third lumen has a diameter of about 0.02 inches.