Optical Needle Dislodgement Detection for Extracorporeal Blood Circuits
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Solution Overview
Problem
Conventional methods for detecting needle dislodgement in extracorporeal blood treatments, particularly venous needle dislodgement, are unreliable, prone to false positives, and lack robustness, posing a risk of fatal blood loss due to delayed detection.
Innovation Solution
A method and system utilizing optical backscatter signals from an optical sensor attached to the extracorporeal blood circuit to identify potential needle dislodgement by analyzing heart rate absence, combined with pressure monitoring and adjusting blood pump speed to verify the event, employing algorithms to filter and calculate heart rate based on arterial and venous pressure data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If pressure monitoring systems with sufficient sensitivity are used to detect small pressure changes, then measurement precision is improved, but system complexity increases and response time is adversely affected due to required damping or averaging
Solution Approach 1:
The patent replaces conventional pressure monitoring systems with an optical sensing system that uses optical backscatter signals to detect needle dislodgement. This substitution eliminates the need for high-sensitivity pressure transducers and their associated damping/averaging requirements, achieving both rapid response and accurate detection without the trade-off between sensitivity and response time.
Solution Approach 2:
The patent introduces an intermediary optical sensing mechanism that detects needle dislodgement indirectly through optical backscatter signals rather than directly through pressure changes. This intermediary approach allows the system to detect dislodgement events without being constrained by the slow response characteristics of conventional pressure monitoring systems.
2Device complexity
If conventional pressure monitoring approaches are used to detect needle dislodgement, then device complexity is reduced, but reliability deteriorates due to false positives and inability to detect small pressure changes
Solution Approach 1:
The patent replaces mechanical pressure monitoring systems with an optical sensing system. This substitution improves reliability by eliminating false positives associated with pressure-based detection while maintaining acceptable device complexity through the use of standard optical components and signal processing algorithms.
Solution Approach 2:
The patent implements a feedback mechanism where the optical sensor continuously monitors optical backscatter signals and provides real-time feedback to the control system. This feedback loop enables the system to detect needle dislodgement events and respond appropriately, improving reliability without requiring complex monitoring infrastructure.
3Difficulty of detecting and measuring
If wetness detectors are placed at or near the patient's access point to detect blood leakage, then detection capability is improved, but reliability deteriorates due to misplaced detectors and unpredictable leak paths
Solution Approach 1:
The patent replaces physical wetness detectors with an optical sensing system that uses optical backscatter signals to detect needle dislodgement. This substitution eliminates the reliability issues associated with wetness detectors, as the optical system can detect dislodgement events before blood leakage occurs and is not affected by detector placement accuracy or leak path predictability.
Solution Approach 2:
The patent enables preliminary detection of needle dislodgement events through optical monitoring before actual blood leakage occurs. By detecting the dislodgement event itself rather than waiting for wetness indicators, the system provides advance warning that eliminates the reliability problems of post-leakage detection 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
Provides a reliable, rapid, and cost-effective solution for detecting needle dislodgement, reducing false alarms, and ensuring timely intervention to prevent fatal blood loss.
Implementation Method 1
searching for a heart rate of a patient by analyzing an optical backscatter signal from an optical sensor attached to the extracorporeal blood circuit
Data Source
AI summary
This disclosure teaches a system and method for monitoring an extracorporeal blood circuit of a patient and identifying a needle dislodgement. The method includes identifying a potential needle dislodgement event based on changes in pressure of the extracorporeal blood circuit, searching for a heart rate of a patient by analyzing an optical backscatter signal from an optical sensor attached to the extracorporeal blood circuit or by analyzing a pressure signal representative of the pressure in the extracorporeal blood circuit, and verifying the potential needle dislodgement event is a needle dislodgement based on the absence of the heart rate.