Single-Connection Blood Pump with Compliance Chamber
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Solution Overview
Problem
Existing extracorporeal blood treatment devices with single patient connections face issues of pressure variations and peaks, which can lead to dialyser membrane blockage and require high anticoagulant doses, while also limiting blood clearance and efficiency.
Innovation Solution
The device employs two blood conveyance apparatuses, one for continuous blood flow through the treatment unit during both arterial and venous phases, with a second apparatus for establishing pressure to ensure consistent blood return, using occluding pumps and a control unit to manage flow rates and pressure, thereby minimizing pressure fluctuations and preventing clotting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single patient connection is used with blood interruption during venous phase, then device complexity is reduced, but pressure peaks occur leading to dialyser membrane blockage
Solution Approach 1:
A compliance chamber is introduced as an intermediary component between the blood pump and the dialyser. This chamber acts as a buffer that absorbs pressure peaks generated during the venous phase when blood is returned to the patient, preventing these pressure spikes from reaching and blocking the dialyser membrane, thus resolving the contradiction between simplified single-connection design and pressure-induced membrane blockage
Solution Approach 2:
The compliance chamber is pre-filled with a compressible medium or designed with compliant walls that can expand to absorb incoming pressure waves before they propagate through the circuit. This beforehand cushioning capacity prevents pressure peaks from causing membrane blockage while maintaining the benefits of single patient connection operation
2Ease of operation
If blood flow through dialyser is interrupted during venous phase, then single needle operation is enabled, but risk of dialyser membrane blockage increases
Solution Approach 1:
The system maintains continuous blood flow through the dialyser by recirculating blood from the venous line back through the dialyser even during the venous phase when blood is being returned to the patient. This continuous circulation prevents blood stasis and reduces the risk of dialyser membrane blockage while still enabling single needle operation through the use of a three-way valve to manage flow paths
3Reliability
If high anticoagulant doses are used to prevent clotting, then dialyser membrane blockage is reduced, but patient safety and treatment quality deteriorate
Solution Approach 1:
The compliance chamber, initially designed to manage pressure peaks, inadvertently creates a low-pressure zone that reduces blood stasis and the tendency toward clotting. This converts the pressure-management function into a secondary benefit of reduced anticoagulant requirements, allowing lower anticoagulant doses to be used effectively while maintaining dialyser patency
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 approach maintains constant pressure in the extracorporeal circuit, reduces the risk of dialyser membrane blockage, allows for improved blood clearance, and potentially lowers anticoagulant requirements, enabling more efficient haemodiafiltration operations with reduced pressure peaks.
Implementation Method 1
a first apparatus (6) for conveying blood
Implementation Method 2
a second apparatus (7) for conveying blood
Implementation Method 3
with a second apparatus (7) for conveying blood, which has means (11) for collecting blood and means (20) for establishing a pressure in the means (11) for collecting blood
Data Source
AI summary
An extracorporeal blood treatment device for operation with a single patient connection, connected by an arterial and a venous blood line to an extracorporeal blood circuit, and a method for operating a blood treatment device with a single patient connection. The blood treatment device has two apparatuses for conveying blood in the arterial and venous blood lines. The second apparatus for conveying blood comprises means for collecting blood and means for establishing a pressure in the means for collecting blood, so that blood collected in the means for collecting blood flows to the patient connection. Furthermore, the blood treatment device has arterial and venous closure elements for interrupting the flow of liquid in the arterial and venous blood lines, as well as a control unit for actuating the two apparatuses for conveying blood and the arterial and venous closure elements. The blood treatment device and the method for operating are characterized in that the first apparatus for conveying blood is operated both during the arterial and venous phases, so that blood flows continuously through the blood treatment unit.