Hemodialysis Replacement Fluid Feedback for Sudden Pressure Changes
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Solution Overview
Problem
Existing hemodialysis devices do not account for sudden pressure changes in the blood circuit, such as kinks, which can lead to unstable fluid replacement due to excessive dialysate flow into the blood circuit.
Innovation Solution
A hemodialysis device with a control system that includes pressure measurement devices and flow rate restriction devices, allowing for feedback control to adjust the flow rate of replacement fluid, stabilizing it even when pressure changes occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a replacement fluid passage is provided between the dialysate circuit and blood circuit for fluid replacement, then fluid replacement function is achieved, but the system becomes vulnerable to sudden pressure changes in the blood circuit causing unstable replacement fluid flow
Solution Approach 1:
The patent implements a feedback control mechanism where the control device continuously monitors pressures in both the dialysate supply passage and blood circuit, compares actual replacement fluid flow rate with target flow rate, and dynamically adjusts the second flow rate restriction device to maintain stable fluid replacement even when sudden pressure changes occur in the blood circuit
Solution Approach 2:
The patent makes the flow rate restriction devices dynamically adjustable during operation. The control device can change the opening degree of the second flow rate restriction device multiple times within one dialysate supply round based on real-time pressure measurements and flow rate feedback, allowing the system to adapt to sudden pressure changes rather than being static
2Speed
If the control device adjusts the second flow rate restriction device multiple times during one dialysate supply round, then the replacement fluid flow rate is quickly stabilized after sudden pressure changes, but the control complexity increases
Solution Approach 1:
The control device performs multiple feedback control adjustments of the second flow rate restriction device during one dialysate supply round by continuously monitoring pressure differences and replacement fluid flow rate, enabling quick stabilization of fluid flow after sudden pressure changes while managing control complexity through systematic feedback loops
Solution Approach 2:
The patent replaces complex mechanical flow control mechanisms with an automated control device that uses pressure sensors and flow rate sensors to electronically regulate the second flow rate restriction device, achieving fast response to pressure changes without requiring complex mechanical adjustment mechanisms
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 device quickly stabilizes replacement fluid flow by adjusting flow rates through multiple feedback controls, ensuring stable fluid replacement during hemodialysis.
Implementation Method 1
connection portion pressure measurement device that measures a pressure of the connection portion of the dialysate supply passage and the replacement fluid passage, and blood circuit pressure measurement device that measures a pressure of the blood circuit
Implementation Method 2
first flow rate restriction device provided at a downstream side of a connection portion with the replacement fluid passage in the dialysate supply passage, second flow rate restriction device provided in the replacement fluid passage
Data Source
Figure 1
Figure 2~3
AI summary
When a pressure change suddenly occurs, a replacement fluid is quickly stabilized. Provided is a hemodialysis device 1 including a replacement fluid passage 5 between a dialysate circuit 4 and a blood circuit 3, the dialysate circuit 4 and the replacement fluid passage 5 being respectively provided with first and second flow rate restriction device MV1 and MV2. A connection portion pressure sensor PG2 for measuring a pressure of a connection portion between a dialysate supply passage 14 and the replacement fluid passage 5, and a vein-side pressure sensor PV (blood circuit pressure measurement device) for measuring a pressure of the blood circuit 3 are included. The control device 6 adjusts an opening degree of the second flow rate restriction device MV2 a plurality of times on the basis of the measured pressure of the connection portion pressure sensor PG2, and the measured pressure of the vein-side pressure sensor PV, for one round, defined as being from when a supply compartment of a chamber provided to the dialysate circuit 4 is filled with a fresh dialysate until all of the fresh dialysate in the supply compartment has been discharged (shown by white rhombuses in the drawing).