Venous Needle Disconnection Detection via Periodic Line Occlusion
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Solution Overview
Problem
Current systems for detecting venous needle disconnection during extracorporeal blood treatment, such as hemodialysis, are not sufficiently accurate and can lead to life-threatening situations due to delayed or missed detection of venous access disruptions, especially when venous pressure fluctuations are caused by patient movements or partial disconnections.
Innovation Solution
A system that includes a pressure sensor in the venous fluid line, a line shut-off mechanism, and a control and evaluation device to measure and analyze the pressure profile over time, determining a representative variable from the pressure curve to detect connection interruptions by comparing it to a reference value, allowing for real-time detection of venous needle disconnections without interrupting patient treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If venous pressure monitoring is used to detect needle disconnection, then detection capability is provided, but measurement precision is insufficient due to pressure fluctuations from patient movements and partial disconnections
Solution Approach 1:
The patent implements periodic occlusion of the venous line at regular intervals during blood treatment. By repeatedly occluding and releasing the venous line, the system creates periodic pressure changes that allow differentiation between true disconnections and transient pressure fluctuations. This periodic action transforms continuous pressure monitoring into discrete measurement events, improving detection reliability.
Solution Approach 2:
The system performs preliminary occlusion of the venous line before actual disconnection can occur during treatment. By proactively creating controlled occlusion conditions, the system establishes a baseline pressure profile that can be compared against subsequent measurements. This preliminary action enables the system to detect deviations indicating disconnection before they become critical safety issues.
2Measurement precision
If continuous venous pressure monitoring is performed, then detection capability is improved, but treatment interruption is required for measurement
Solution Approach 1:
Instead of continuous monitoring that would require constant treatment interruption, the system employs periodic occlusion at predetermined intervals. This allows blood treatment to proceed continuously while detection measurements are taken at discrete time points. The periodic nature ensures adequate sampling for detection while minimizing disruption to the overall treatment process and maintaining blood flow continuity.
Solution Approach 2:
The system maintains continuous blood treatment flow while performing detection measurements. The occlusion events are brief and scheduled such that they do not significantly interrupt the overall treatment continuity. Blood pumping and dialysis processes continue uninterrupted between measurement events, preserving treatment productivity while enabling periodic detection.
3Device complexity
If simple pressure threshold comparison is used, then device complexity is reduced, but detection reliability fails under varying pressure conditions
Solution Approach 1:
The system establishes a feedback mechanism where each occlusion event generates pressure data that is compared against reference values from previous measurements. The control device uses this feedback to dynamically adjust detection thresholds and identify deviations indicating disconnection. This feedback loop enables adaptive detection that maintains high reliability without requiring complex adjustable parameters, as the system learns from its own measurement history.
Solution Approach 2:
The system detects disconnections by identifying changes in pressure parameters during occlusion events rather than using fixed thresholds. By monitoring parameter changes such as pressure rise rate, peak pressure values, and decay characteristics, the system achieves reliable detection across varying operating conditions. This parameter-change approach maintains device simplicity while improving reliability over static threshold methods.
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 accurate and timely detection of venous needle disconnections, reducing the risk of life-threatening blood flow issues by differentiating between connected and disconnected states, even during patient movements, and providing a reliable method to distinguish between connection and disconnection pressures.
Implementation Method 1
a pressure sensor (41) arranged in the first fluid line or in the second fluid line for measuring a pressure prevailing in the first or second fluid line
Data Source
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AI summary
The described system serves to detect an interruption of the connection between a blood treatment device and a patient's blood circulation, which is connected to the blood treatment device via a first connection device that can be attached to a first fluid line, a line shut-off device for shutting off the first fluid line located between the blood treatment device and the connection device, a second fluid line located between the blood treatment device and the patient's blood circulation, a pressure sensor located in the first or second fluid line for measuring the pressure prevailing in the first or second fluid line, and a control and evaluation device that evaluates the pressure profile over time of the pressure measured by the pressure sensor during a shutdown of the first fluid line.to detect a connection interruption or fault between the first connection device and the patient's blood circulation, wherein the control and evaluation device determines a quantity representative of the pressure profile from the pressure profile, compares the representative quantity with a reference value, and concludes, based on the result of the comparison, whether or not a connection interruption or fault exists between the first connection device and the patient's blood circulation.