Non-invasive Fluid Velocity Sensing in Dialysis Systems
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Solution Overview
Problem
Current dialysis systems, particularly for home hemodialysis, face challenges in accurately controlling fluid flow and ultrafiltration rates, which can lead to adverse effects on patients due to the complexity and cost of disposable cassettes and the need for invasive sensors.
Innovation Solution
A non-invasive fluid velocity sensing system is introduced, using optical or heat pulse sensors integrated into the dialysis instrument, which measures fluid flow rates without contacting the dialysis fluid, enabling simple and cost-effective volumetric control by determining the total volume of fluid delivered and removed, and calculating real-time ultrafiltration rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive fluid velocity sensors are used to measure flow rates, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces invasive mechanical/physical sensors with optical sensing technology. The optical sensor system uses light absorption or scattering properties of the fluid to determine flow rate, eliminating the need for direct contact with the fluid and reducing system complexity while maintaining measurement precision.
Solution Approach 2:
The patent introduces an intermediary optical measurement method that indirectly measures fluid flow rate through light interaction with the fluid rather than direct mechanical sensing. This intermediary approach allows non-invasive measurement and simplifies the overall sensor system architecture.
2Measurement precision
If invasive sensors are used for fluid velocity sensing, then measurement accuracy is improved, but ease of operation deteriorates due to sterilization and disposal requirements
Solution Approach 1:
The patent replaces invasive physical sensors that require sterilization with non-contact optical sensors. The optical sensors measure fluid velocity through light interaction without penetrating or contacting the fluid stream, eliminating sterilization requirements and simplifying operational procedures for home dialysis settings.
Solution Approach 2:
The patent enables the use of disposable optical sensor components or integrated optical circuits that do not require sterilization. These disposable optical sensing elements can be easily replaced without complex sterilization processes, improving ease of operation for single-use dialysis systems.
3Manufacturing precision
If complex disposable cassettes with invasive sensors are used, then fluid flow control accuracy is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive invasive sensors and complex flow control mechanisms with cost-effective optical sensing integrated into simple disposable cassettes. The optical sensors can be implemented as integrated circuits or simple optical components that are inexpensive to manufacture at scale, while still providing accurate flow measurement and control.
Solution Approach 2:
The patent designs the optical sensor system to perform multiple functions including flow rate measurement, fluid level detection, and potentially other diagnostic functions within a single integrated platform. This multi-functionality reduces the overall component count and manufacturing complexity of the disposable cassette while maintaining precise fluid flow control.
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 system ensures accurate and safe ultrafiltration control, minimizing errors in fluid balance and reducing the risk of rapid fluid removal, thereby improving patient safety and treatment efficacy while simplifying the disposable cassette design and reducing costs.
Implementation Method 1
optical or heat pulse sensors integrated into the dialysis instrument, which measures fluid flow rates without contacting the dialysis fluid
Implementation Method 2
optical or heat pulse sensors integrated into the dialysis instrument, which measures fluid flow rates without contacting the dialysis fluid
Data Source
AI summary
A dialysis system includes a dialysis instrument including a blood pump, a dialysate inlet pump, a dialysate outlet pump, and at least one fluid velocity sensor, each sensor including an emitter and a receiver, a dialyzer arranged (i) to receive blood pumped by the blood pump, (ii) to receive fresh dialysate pumped by the dialysate inlet pump and (iii) such that used dialysate is pumped from the dialyzer by the dialysate outlet pump, and a disposable cassette including a to-dialyzer dialysate pathway carrying dialysate pumped by the dialysate inlet pump and a from-dialyzer dialysate pathway carrying used dialysate pumped by the dialysate outlet pump, wherein at least one of the to-dialyzer dialysate pathway or the from-dialyzer dialysate pathway includes at least one sensing area so positioned and arranged such that when the disposable cassette is mounted to the instrument, the sensing area is coupled operably with both the emitter and the receiver of the at least one fluid velocity sensor.