Dialyzer Membrane Microleak Detection via Pneumatic Pressure Testing
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Solution Overview
Problem
Existing methods fail to accurately detect microleaks in dialyzer membranes with leak rates less than 0.5 ml/min, necessitating unnecessary disinfection of dialysis devices to prevent cross-contamination.
Innovation Solution
A method involving the emptying of dialyzer chambers, building up a test pressure, and measuring pressure drop or air bubble movement over time in the dialyzer system post-treatment, allowing for precise detection of membrane leaks without requiring subsequent disinfection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If previously known pressure measurement methods are used, then leak detection is possible, but microleaks with leak rate less than 0.5 ml/min cannot be detected
Solution Approach 1:
The method performs preliminary actions by completely draining the dialyzer of blood and dialyzate before the leak test, and isolating chambers with clamps. This preparation removes interfering fluids that could mask microleak detection, enabling precise measurement of even minimal pressure changes or air bubble formations that indicate leaks below 0.5 ml/min.
Solution Approach 2:
The invention applies pneumatic principles by introducing air into the drained dialyzer chambers and measuring pressure changes or air bubble formations. The test pressurizes the empty chambers with air, and any leak causes measurable pressure drops or visible air bubbles entering the opposite chamber, providing sensitive detection of microleaks that liquid-based methods miss.
2Reliability
If a leak is detected in the dialyzer membrane, then patient safety is protected, but the dialysis device requires disinfection before subsequent treatment
Solution Approach 1:
The invention replaces the complex biological disinfection process with a simple mechanical/physical leak detection method. By using air pressure testing and bubble detection, the system provides clear binary results (leak present/absent) that directly determine whether disinfection is needed, eliminating unnecessary disinfection cycles for intact dialyzers and saving time while maintaining patient safety.
3Ease of manufacture
If the dialyzer is not completely drained before leak testing, then blood or dialyzate remains in the chambers, but pressure measurement accuracy is reduced
Solution Approach 1:
The method extracts and removes all blood and dialyzate from the dialyzer chambers before performing the leak test. This complete extraction eliminates interfering fluids that would otherwise compress under pressure and mask the subtle pressure changes or air bubble formations that indicate microleaks, thereby maximizing measurement precision while maintaining procedural simplicity through systematic draining and isolation steps.
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 precise detection of microleaks and intact dialyzer membranes, reducing unnecessary disinfection procedures and ensuring patient safety by distinguishing between intact and defective membranes based on pressure development and air bubble presence.
Implementation Method 1
building up a test pressure in the emptied blood chamber or in the emptied dialyzate chamber
Implementation Method 2
measuring the pressure drop over time in the emptied blood chamber or dialyzate chamber or in the line system respectively in fluid communication therewith
Implementation Method 3
Due to the solubility of gas in air, there is always a slight pressure drop on that side at which the test pressure was applied; however, with a membrane leak the pressure drop is considerably larger and/or a movement of air bubbles takes place into the non-emptied side
Data Source
AI summary
The present invention relates to a method for checking a dialyzer for the presence of a leak in the semipermeable membrane of the dialyzer, wherein the membrane divides the inner dialyzer space into a least one blood chamber and into at least one dialyzate chamber, wherein the blood chamber is flowed through by blood in the operation of the dialyzer and is in fluid communication with a blood-side line system and the vascular system of the patient, and wherein the dialyzate chamber is flowed through by dialysis fluid in the operation of the dialyzer and is in fluid communication with a dialyzate-side line system, wherein the method comprises the following steps:a) emptying the blood chamber or the dialyzate chamber of blood and of dialysis fluid respectively and keeping the fluid (blood or dialyzate) in the non-emptied dialyzate chamber or blood chamber;b) building up a test pressure by means of a gas, in particular by means of air, in the emptied blood chamber or in the emptied dialyzate chamber; andc) measuring the pressure drop over time in the emptied blood chamber or in the emptied dialyzate chamber or in the line system respectively in fluid communication therewith and/or measuring the pressure increase in the non-emptied blood chamber or in the non-emptied dialyzate chamber or in the line system respectively in fluid communication therewith or measuring the number of air bubbles or of a parameter correlated with the number of air bubbles in the non-emptied blood chamber or in the non-emptied dialyzate chamber or in a line system respectively in fluid communication therewith,wherein the steps a) to c) are carried out subsequent to the blood treatment of the patient and subsequent to the disconnection of the patient from the blood-side line system.