Airless Drip Chamber with Microporous Filter for Hemodialysis
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Solution Overview
Problem
Existing extracorporeal liquid circuits in hemodialysis expose blood to air, leading to clotting and the need for anticoagulants, which increases the risk of clots and complications during treatment.
Innovation Solution
An airless drip chamber with a microporous filter at the top and a dam between entry and exit ports, designed to prevent air from entering the blood circuit, allowing air to escape while maintaining a liquid barrier to prevent protein accumulation on the filter, thus reducing the risk of clotting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a traditional drip chamber is used to remove air from blood, then air can be vented from the circuit, but blood is exposed to air which causes clotting and requires anticoagulants
Solution Approach 1:
The patent introduces a hydrophobic microporous filter as an intermediary component between the blood and the air environment. This filter allows air bubbles to pass through while blocking blood and proteins, serving as a mediator that enables air venting without direct air-blood contact. The filter membrane acts as the intermediary that resolves the contradiction by selectively permitting gas passage while preventing liquid and protein exposure to air.
Solution Approach 2:
The patent creates an inert or air-free environment within the drip chamber by using a hydrophobic barrier that prevents air from contacting the blood. The chamber is designed to maintain a liquid-filled, air-excluded zone where blood flows without exposure to atmospheric air, thereby eliminating the harmful effect of air-induced clotting while still allowing air removal through the hydrophobic filter.
2Object-affected harmful factors
If a microporous filter is placed at the top of the chamber to allow air escape, then air can be removed from the blood, but proteins may accumulate on the filter causing it to wet and fail
Solution Approach 1:
The patent introduces a second intermediary component - a hydrophilic barrier or liquid seal - positioned between the blood and the hydrophobic microporous filter. This intermediate liquid layer or hydrophilic membrane prevents direct contact between blood proteins and the hydrophobic filter surface, thereby protecting the filter from protein accumulation and wetting while still allowing air bubbles to pass through the hydrophobic filter to the atmosphere.
Solution Approach 2:
The chamber design allows the blood flow itself to serve the dual function of both the processed fluid and the protective barrier. The blood or priming solution fills the chamber to a level that naturally creates a liquid seal over the hydrophobic filter, using the fluid's own weight and surface tension to prevent protein contact with the filter while maintaining air venting capability.
3Reliability
If anticoagulants are added to prevent clotting, then clot formation is reduced, but the risk of complications increases
Solution Approach 1:
The patent converts the harmful effect of air exposure (which causes clotting) into a beneficial design feature by creating an air-excluded environment. Instead of trying to manage the harmful consequence (clotting) through anticoagulants, the invention eliminates the root cause (air-blood contact) through the hydrophobic filter and liquid seal design, thereby preventing clotting naturally without requiring anticoagulant medications and their associated complications.
Data Source
Figure 1
Figure 2~2C
Figure 2D~2E
AI summary
A chamber is described for use in an extracorporeal fluid system. The chamber has a bottom entry port and a bottom exit port. A microporous filter at the top of the chamber allows air in the fluid to vent from the chamber. In use, the chamber is filled with saline. Blood is then introduced into the chamber. A layer of saline is above a layer of blood in the chamber. The saline stagnates as the blood flows through the chamber. The saline keeps the blood from contacting the filter and depositing protein on the filter.