Dialyzer Emptying by Negative Pressure Across the Membrane

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing extracorporeal blood treatment devices require multiple manual steps to completely empty the dialyzer after blood treatment, leading to high disposal weights and increased interaction time for nursing staff, with prior art solutions either requiring additional components or not fully addressing both sides of the dialyzer.

Innovation Solution

An extracorporeal blood treatment device with a control unit that automatically empties the dialyzer by creating negative pressure in the dialysis fluid circuit, causing fluid to transfer from the blood side to the dialysis fluid side, followed by air to displace any remaining fluid out of the dialysis fluid side, using existing components and minimizing manual interaction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If manual emptying steps are used to remove fluid from the dialyzer, then the disposal weight is reduced, but the nursing staff must interact with the device multiple times and wait for each step

Engineering Contradiction:
Improvedisposal weightVSAvoidstaff interaction time
Core Design Contradiction:
Loss of substanceVSLoss of time

Solution Approach 1:

The system performs preliminary actions by automatically executing the emptying sequence without requiring nursing staff to be present for each step. The control unit initiates and manages the entire emptying process, including creating negative pressure, monitoring fluid removal, and completing the sequence, thereby reducing both disposal weight and staff time investment

Inventive Principle:
Principle #10Preliminary action

2Device complexity

If the dialyzer is emptied using only the dialysis fluid circuit, then the procedure is simple, but the blood-side fluid remains in the dialyzer and the disposal weight remains high

Engineering Contradiction:
Improveemptying procedure complexityVSAvoiddisposal weight
Core Design Contradiction:
Device complexityVSLoss of substance

Solution Approach 1:

The system applies pneumatic principles by creating negative pressure through a vacuum source connected to the dialysis fluid circuit. This negative pressure differential forces fluid from the blood side across the semipermeable membrane into the dialysis fluid side, where it is then removed by the drain pump, achieving complete emptying while maintaining procedural simplicity

Inventive Principle:
Principle #29Pneumatics and hydraulics

Solution Approach 2:

The system changes the pressure parameter by creating a negative pressure environment in the dialysis fluid circuit. This pressure change drives the fluid transfer across the membrane and enables complete removal of blood-side fluid, transforming the emptying process from incomplete to thorough without increasing complexity

Inventive Principle:
Principle #35Parameter changes

3Extent of automation

If additional components are added to achieve automated emptying, then the automation level increases, but the device complexity and cost increase

Engineering Contradiction:
Improveemptying automation levelVSAvoiddevice component count
Core Design Contradiction:
Extent of automationVSDevice complexity

Solution Approach 1:

The system achieves automation by making the dialysis fluid circuit multi-functional. It serves both its primary function of providing dialysis fluid during treatment and a secondary function of enabling automated emptying through negative pressure creation and fluid removal. This eliminates the need for separate dedicated emptying components

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system implements self-service automation where the control unit automatically manages the emptying process using existing components. The vacuum source, drain pump, and control unit work together autonomously to complete the emptying sequence without requiring additional manual intervention or specialized emptying hardware

Inventive Principle:
Principle #25Self-service

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 solution achieves complete and automated dialyzer emptying, reducing disposal weight and staff interaction, while using only standard device components, and ensuring efficient fluid and air displacement without exceeding dialyzer pressure limits.

Implementation Method 1

a control unit which is designed to automatically empty the dialyzer after the end of the blood treatment therapy by setting a negative pressure in the dialysis fluid circuit and thereby causing a fluid to pass from the blood side across the membrane of the dialyzer into the dialysis fluid side

Methodology Applied
Scientific EffectNegative pressure: Pressure Gradient

Implementation Method 2

causing fluid to pass from the blood side across the membrane of the dialyzer into the dialysis fluid side

Methodology Applied
Scientific EffectFluid transfer across membrane: Permeation

Implementation Method 3

air passes from the blood side across the membrane to the dialysis fluid side and displaces fluid out of the dialyzer

Methodology Applied
Scientific EffectGas displacement: Pressure Gradient

Data Source

PatentEP4225397B1Automated emptying of a dialyzer after a blood treatment therapy
Publication Date: 2026.03.11 B BRAUN AVITUM
  • EP4225397B1 patent drawingFigure 1~2
  • EP4225397B1 patent drawingFigure 3~4
  • EP4225397B1 patent drawingFigure 5~7

AI summary

The present disclosure relates to an extracorporeal blood treatment apparatus (2) having: an extracorporeal circuit (4); a dialysis fluid circuit (8); and a dialyzer (6) comprising a blood side (9) and a dialysis fluid side (11), the blood side (9) and the dialysis fluid side (11) being separated from one another by way of a membrane (10). The blood treatment apparatus (2) contains a control unit (60) which is configured to automatically empty the dialyzer (6) by setting a reduced pressure or negative pressure in the dialysis fluid circuit (8) and by a passage of fluid from the blood side (9) to the dialysis fluid side (11) via the membrane (10) of the dialyzer (6) accompanying this. Further, once the fluid from the extracorporeal circuit (4) has passed in its entirety from the blood side (9) to the dialysis fluid side (11) via the membrane (10) and the blood side (9) of the dialyzer (6) has been emptied, the control unit (60) is configured to bring about a passage of air from the blood side (9) to the dialysis fluid side (11) via the membrane (10) and a displacement of the fluid out of the dialysis fluid side (11) toward a dialysis fluid outflow (54) by continued setting of the reduced pressure or negative pressure in the dialysis fluid circuit (8).