Peritoneal Dialysis Pressure Sensing With Temperature Compensation

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Solution Overview

Problem

Existing automated peritoneal dialysis (APD) systems face issues with sealing, noise, and inefficiencies in fluid management, particularly in pneumatic cassette systems, which can delay treatment start times and cause customer dissatisfaction.

Innovation Solution

A peristaltic pump-driven APD system with a disposable cassette that includes a peristaltic pump actuator, pinch valve actuators, and pressure sensors, along with a weigh scale for accurate fluid management, and a user interface for easy operation, reducing noise and improving sealing and fluid handling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If pneumatic cassette systems are used for automated peritoneal dialysis, then fluid management functions can be integrated, but sealing issues and noise problems occur that delay treatment and reduce customer satisfaction

Engineering Contradiction:
Improveautomated fluid managementVSAvoidsealing performance
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent replaces the pneumatic actuation system with a motor-driven mechanical system. The motor (220) drives a drive shaft (222) with eccentrics (224) that convert rotational motion into linear reciprocating motion of the plunger (202), eliminating the need for pneumatic actuators and their associated sealing problems while maintaining automated fluid management functionality.

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

Solution Approach 2:

The patent extracts and removes the pneumatic system components from the disposable cassette assembly. By using a motor housed in the reusable portion of the system that mechanically actuates the pump in the disposable cassette, the design eliminates pneumatic seals and air pathways that were causing reliability issues.

Inventive Principle:
Principle #2Taking out (Extraction)

2Extent of automation

If pneumatic cassette systems are used for automated peritoneal dialysis, then fluid management functions can be integrated, but significant noise is generated that causes customer dissatisfaction

Engineering Contradiction:
Improveautomated fluid managementVSAvoidnoise
Core Design Contradiction:
Extent of automationVSObject-generated harmful factors

Solution Approach 1:

The patent replaces the pneumatic actuation system with a motor-driven mechanical system. The motor (220) drives a drive shaft (222) with eccentrics (224) that convert rotational motion into linear reciprocating motion of the plunger (202), eliminating the need for pneumatic actuators and their associated sealing problems while maintaining automated fluid management functionality.

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

3Reliability

If pressure sensors are integrated into the disposable cassette, then patient safety can be improved through monitoring, but device complexity increases

Engineering Contradiction:
Improvepatient safetyVSAvoidsystem structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the pressure sensing functionality into a separate, dedicated component (pressure sensor (204) with pressure transmission fluid chamber (206)) that interfaces with the disposable cassette but can be housed in the reusable portion. This modular approach allows pressure monitoring capability while managing complexity through separation of sensing and processing functions.

Inventive Principle:
Principle #2Taking out (Extraction)

4Loss of substance

If supply containers are reused as drain containers, then disposable costs can be reduced, but cleaning and sanitation requirements increase

Engineering Contradiction:
Improvedisposable material consumptionVSAvoidcleaning and sanitation
Core Design Contradiction:
Loss of substanceVSEase of manufacture

Solution Approach 1:

The patent implements a system where supply containers (106, 108) can be reused as drain containers (104) after appropriate processing. The reusable portion of the system facilitates this transition, and the system includes functionality to flush and sanitize containers between uses, enabling circular material flow while maintaining hygiene requirements.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The system includes self-sanitizing capabilities through automated flushing sequences. The pump and valve system can automatically rinse and sanitize containers between supply and drain uses, reducing manual cleaning requirements while enabling container reuse.

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 system provides accurate, quiet, and efficient fluid management within safe patient pressure limits, simplifies used dialysis fluid removal, and reduces overall disposable costs by reusing supply containers as drain containers, enhancing the user experience.

Implementation Method 1

a peristaltic pump actuator, pinch valve actuators

Methodology Applied
Scientific EffectPeristalsis: Peristalsis

Implementation Method 2

pressure sensors

Methodology Applied
Scientific EffectPressure sensing: Pressure Increase

Data Source

PatentEP4333928B1Automated peritoneal dialysis system including enhanced pressure sensing features
Publication Date: 2026.02.25 BAXTER INT INC
  • EP4333928B1 patent drawingFigure 1
  • EP4333928B1 patent drawingFigure 2
  • EP4333928B1 patent drawingFigure 3

AI summary

An automated peritoneal dialysis system (10) comprising: a dialysis fluid pump actuator (60); a dialysis fluid carrying set (120) including a flexible sheet (136); a temperature sensor (38) positioned and arranged to sense a temperature of the dialysis fluid flowing through the dialysis fluid carrying set (120); a pressure sensor (36a, 36b) positioned and arranged to contact the flexible sheet (136) when the dialysis fluid carrying set (120) is loaded for operation with the dialysis fluid pump actuator (60); and a control unit (50) configured to (i) precondition the flexible sheet (136) for operation with the pressure sensor (36a, 36b) by causing the dialysis fluid pump actuator (60) to apply pressure to the flexible sheet (136) and (ii) use an output from the temperature sensor (38) in a compensation algorithm that modifies an output from the pressure sensor (36a, 36b).