Dialyser Integrity Monitoring via Pressure Decay Analysis
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Solution Overview
Problem
Existing extracorporeal blood treatment devices risk interruption during dialysis if a dialyser with a defective semi-permeable membrane is used, as blood can leak into the hydraulic system, requiring complex disinfection and potential patient safety risks.
Innovation Solution
A method and device for monitoring dialyser integrity before blood treatment, using a pressure difference across the semi-permeable membrane to detect defects, with a control and arithmetic unit configuring pumps and pressure sensors to assess the membrane's integrity before wetting the blood side, allowing for early detection and replacement of defective dialysers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a dialyser with a defective semi-permeable membrane is used during blood treatment, then the blood treatment can proceed, but blood may leak into the hydraulic system causing treatment interruption and requiring complex disinfection
Solution Approach 1:
The patent applies preliminary action by performing an integrity test on the dialyser membrane before the blood treatment begins. The control unit initiates a test in which a test fluid is pumped through the dialyser and the presence of test fluid in the blood chamber is detected. This preliminary detection allows defective dialysers to be identified and replaced before actual blood treatment, ensuring membrane integrity and preventing blood leakage during treatment.
2Ease of repair
If the hydraulic system is disinfected after blood leakage is detected, then the system can be reused, but complex disinfection procedures are required and treatment time is lost
Solution Approach 1:
The patent prevents the need for complex disinfection procedures by performing preliminary integrity testing before blood treatment. By detecting membrane defects beforehand, the system avoids blood leakage entirely, eliminating the need for subsequent disinfection processes and associated time losses. The control unit prevents blood treatment from starting if a defect is detected, thereby avoiding contamination and the complex repair/disinfection cycle.
3Measurement precision
If pressure hold tests are performed to test fluid system tightness, then system integrity can be verified, but the tests require high or low pressure establishment and cannot detect membrane defects during normal operation
Solution Approach 1:
The patent uses a hydraulic approach by pumping a test fluid through the dialyser membrane during normal treatment conditions and detecting its presence in the blood chamber. This method verifies membrane integrity under operational pressure differentials rather than requiring separate high/low pressure hold tests, enabling continuous monitoring without additional complex pressure testing equipment or procedures.
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 approach prevents blood treatment interruptions by ensuring only intact dialysers are used, enhancing patient safety by identifying membrane defects before treatment and reducing the need for complex disinfection procedures.
Implementation Method 1
a dialyser which is divided by a semi-permeable membrane into the blood chamber and a dialysate chamber
Implementation Method 2
the pressure difference between the blood and the dialysate is generally positive over the length of the membrane
Data Source
AI summary
The invention relates to an extracorporeal blood treatment device for carrying out an extracorporeal blood treatment, in which blood flows in an extracorporeal blood circuit A through the blood chamber 2 of a dialyser 1 which is divided by a semi-permeable membrane 4 into the blood chamber 2 and a dialysate chamber 3. The invention further relates a method for monitoring the integrity of a dialyser 1. The blood treatment device provides a preparation mode in preparation for the blood treatment, in which the dialysate chamber 3 of the dialyser 1 (filter) is filled with a liquid, while the blood chamber 2 is not filled with blood, and a treatment mode following the preparation mode, in which blood is conveyed through the blood chamber 2. For monitoring the integrity of the dialyser 1, in the preparation mode the fluid system B including the dialysate chamber 3, or a portion of the fluid system including the dialysate chamber, is filled with a liquid. At this time, however, the blood chamber 2 is not filled with blood. After the membrane of the dialyser 1 has been wetted with liquid, liquid is removed from the fluid system B including the dialysate chamber 3 such that a low pressure p is established in the fluid system. The control and arithmetic unit 29 of the blood treatment device is so configured that the increase in the amount of the low pressure p, measured by means of a pressure measuring apparatus 34, in a given time interval is determined, and the leakage rate LR of the fluid system is determined from the increase in the amount of the low pressure in a given time interval and the compliance C of the fluid system B including the dialysate chamber 3. A lack of integrity of the dialyser is then concluded on the basis of the determined leakage rate LR.