Dialysis Fluid Proportioning With Conductivity-Based Remixing

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Solution Overview

Problem

Existing peritoneal dialysis systems lack efficient and automated methods for preparing dialysis fluid at the point of care, compromising safety and consistency.

Innovation Solution

A system and method for preparing dialysis fluid using a daily sterile disposable fluid circuit, incorporating a controller to manage pinch clamps and peristaltic pumps for precise mixing and conductivity/temperature sensors to ensure batch quality, enabling automated preparation of dialysis fluid at the point of care.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If automated preparation systems are implemented, then productivity and consistency are improved, but device complexity increases

Engineering Contradiction:
Improvemedicament preparation efficiencyVSAvoidsystem complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system is divided into modular components including a controller, pinch clamps for flow control, peristaltic pumps for fluid transport, and separate sensing modules for conductivity and temperature measurement. Each component performs a specific function, allowing independent optimization and maintenance while contributing to overall automated preparation efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The peristaltic pumps and pinch clamps are controlled automatically by the controller based on pre-programmed protocols, enabling the system to perform mixing and fluid transport without manual intervention. The conductivity and temperature sensors continuously monitor parameters and provide feedback to the controller for automatic adjustments, maintaining quality standards autonomously.

Inventive Principle:
Principle #25Self-service

2Manufacturing precision

If precise control mechanisms are added, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improvebatch quality consistencyVSAvoidcontrol system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Conductivity sensors and temperature sensors continuously measure the dialysis fluid parameters during preparation and provide real-time feedback to the controller. The controller compares measured values against target ranges and automatically adjusts pump speeds and clamp positions to maintain precision within specified tolerances, ensuring batch quality consistency.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

Manual monitoring and adjustment of fluid preparation parameters are replaced with automated electronic control systems. The controller uses electronic signals to actuate pinch clamps and peristaltic pumps, replacing manual valve turning and pump operation. This substitution enables more precise and consistent control while reducing human error.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If automated preparation is implemented, then reliability is improved, but ease of operation decreases

Engineering Contradiction:
Improvepreparation safetyVSAvoiduser interaction complexity
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The system performs self-monitoring through conductivity and temperature sensors that continuously verify fluid quality parameters. The controller automatically detects deviations from target ranges and corrects them without user intervention, maintaining reliability while requiring minimal operational input from the user.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system uses disposable fluid circuits and replaceable sensor modules that can be quickly exchanged between uses. This approach maintains high reliability by ensuring each preparation cycle uses fresh, sterile components while simplifying operation through rapid component replacement rather than complex cleaning and sterilization procedures.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

Ensures safe and consistent preparation of dialysis fluid by maintaining predefined pressure and conductivity standards, ensuring reliable and efficient production for patient use.

Implementation Method 1

a peristaltic pump configured to engage with the fluid circuit to move the dialysis fluid into and out of the mixing container

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Implementation Method 2

conductivity/temperature sensors to ensure batch quality

Methodology Applied
Scientific EffectElectrical Conductivity: Conduction (electrical)

Implementation Method 3

conductivity/temperature sensors to ensure batch quality

Methodology Applied
Scientific EffectTemperature:

Implementation Method 4

incorporating a controller to manage pinch clamps and peristaltic pumps for precise mixing

Methodology Applied
Scientific EffectMechanical Constriction: Mechanical Force

Data Source

PatentEP4232878B1Medicament preparation device
Publication Date: 2025.07.23 NXSTAGE MEDICAL INC
  • EP4232878B1 patent drawingFigure 1A
  • EP4232878B1 patent drawingFigure 1B
  • EP4232878B1 patent drawingFigure 1C

AI summary

A proportioning device includes a proportioning machine with a temperature-compensating conductivity sensor, a controller, and pump actuator. A fluid circuit is engageable with the pump actuator, has connections for a source of water and one or more medicament concentrates, and includes a mixing container. The controller is configured to mix contents of the mixing container at a first time and to sample fluid from the mixing container, to pass the samples from the mixing container through the temperature-compensating conductivity sensor at different points in time as the fluid flows from the mixing container. The controller is further configured to mix contents of the mixing container a second time if the conductivities differ by a predefined magnitude.