Recirculation Measurement via Diffusion Equilibrium in Dialysis
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Solution Overview
Problem
Existing methods for measuring recirculation during extracorporeal blood treatment, such as hemodialysis, require additional equipment or procedural efforts like temperature control devices or separate blood samples, which are time-consuming and increase operational costs.
Innovation Solution
A device and method that use an optically operating sensor on the dialysis fluid side to detect blood component concentrations without the need for additional equipment, by locking dialysis fluid in the dialyzer to establish a diffusion equilibrium, allowing the measurement of systemic blood component concentration without a separate blood sample.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature control devices or separate blood samples are used to measure recirculation, then measurement precision is improved, but device complexity and operational time increase
Solution Approach 1:
The dialysis fluid itself serves as the measurement medium, utilizing its natural flow and composition through the dialyzer to enable recirculation measurement without requiring external temperature control devices or separate blood sampling systems. The system uses the dialysis fluid's inherent properties and the existing dialyzer structure to perform the measurement function.
Solution Approach 2:
The dialysis fluid serves multiple functions: it performs the primary dialysis function of removing waste products from blood while simultaneously serving as the measurement medium for recirculation detection. The existing dialyzer structure serves both treatment and measurement purposes, eliminating the need for dedicated measurement equipment.
2Measurement precision
If separate blood samples are taken to determine systemic blood component concentration, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs preliminary concentration equalization during the dialysis process itself, allowing the dialysis fluid to reach equilibrium with the blood components naturally during normal operation. This eliminates the need for separate pre-treatment blood sampling to obtain baseline concentration data.
Solution Approach 2:
The dialysis fluid acts as an intermediary medium that transfers blood component information to the measurement sensor. Instead of directly measuring blood components through separate sampling, the system measures the concentration of these components in the dialysis fluid, which has equilibrated with the blood, thereby obtaining equivalent measurement data without direct blood sampling.
3Measurement precision
If diffusion equilibrium is established by locking dialysis fluid in the dialyzer, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system dynamically adjusts the dialysis fluid flow state between normal circulation mode and locked equilibrium mode. A control valve selectively closes to trap dialysis fluid in the dialyzer when measurement is required, and opens to resume normal operation. This dynamic switching enables the system to transition between treatment and measurement functions without permanent structural modifications.
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
Enables efficient and automated recirculation measurement during blood treatment, reducing equipment requirements and time, and providing a fully automated, cost-effective solution for determining recirculation levels.
Implementation Method 1
within a time period, determined by a time value stored in a data set or manually entered, the concentration of at least one selected or selectable blood component between the blood in the extracorporeal blood circuit and the dialysis fluid trapped in the dialyzer is equalized exclusively through diffusion
Implementation Method 2
a sensor device at or downstream of the dialysis fluid outlet of the dialyzer, which is adapted to measure, in particular optically, blood components that have passed through the filter membrane
Data Source
Figure 1~4
AI summary
The invention relates to an extracorporeal blood treatment machine (1) having a dialyser (2) and a sensor device (28), which is downstream of the dialyser (2) on a dialysis fluid side and is electrically connected to a control and computing unit (30), which is intended and designed to both qualitatively and quantitatively determine, on the basis of the measurement signals of the sensor device (28), at least one preferably selected or selectable blood component in the used dialysis fluid. The control and computing unit (30) is further intended and adapted to put the extracorporeal blood treatment machine into a mode in which a dialysis fluid amount is confined within the dialyser (2) at least until the concentration of the blood component on the dialysis fluid side and the blood side of the dialyser (2) is in equilibrium, which equilibrium is no longer changing or is only still changing to an unsubstantial degree, and thereupon to switch the blood treatment machine into a mode in which the dialysis fluid flow is permitted to leave the dialyser (2) in order to feed the previously confined dialysis fluid amount as a dialysis fluid bolus to the sensor device (28) for determining the blood component concentration contained therein.