Extracorporeal Circuit Optical Sensing for Needle Dislodgement Detection

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Solution Overview

Problem

Existing methods for detecting needle dislodgement in extracorporeal blood treatments, particularly venous needle dislodgement, are unreliable, prone to false positives, and fail to provide rapid detection, which can lead to fatal blood loss due to delayed detection.

Innovation Solution

A system and method utilizing optical backscatter signals from an optical sensor attached to the extracorporeal blood circuit to identify a potential needle dislodgement by analyzing heart rate absence, combined with pressure signal analysis and a blood pump speed reduction to verify the event.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Difficulty of detecting and measuring

If pressure monitoring is used to detect needle dislodgement, then detection capability is improved, but false positives increase and system reliability deteriorates

Engineering Contradiction:

Improveneedle dislodgement detection capabilityVSAvoiddetection reliability

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The detection system is divided into multiple independent sensing zones along the blood circuit, each with its own optical sensor. This segmentation allows the system to identify the specific location of needle dislodgement and distinguish it from other pressure changes, reducing false positives while maintaining high detection capability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An optical sensor acts as an intermediary between the blood circuit and the detection system. The optical sensor detects changes in optical properties of blood caused by needle dislodgement, converting these physical changes into detectable signals without requiring direct mechanical contact, thereby improving reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If pressure monitoring sensitivity is increased to detect small pressure changes, then detection precision is improved, but response time deteriorates due to required damping and averaging

Engineering Contradiction:

Improvepressure change detection precisionVSAvoidresponse time

Core Design Contradiction:

Measurement precisionVSSpeed

Solution Approach 1:

The system replaces mechanical pressure monitoring with optical sensing. Optical sensors detect changes in blood's optical properties directly without requiring mechanical damping or signal averaging, achieving both high measurement precision and fast response time simultaneously.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The optical sensor performs periodic measurements of blood's optical properties at high frequency. This periodic sampling allows the system to detect rapid pressure changes in real-time without needing to apply damping or averaging filters, maintaining both precision and speed.

Inventive Principle:

Principle #19Periodic action

3Difficulty of detecting and measuring

If wetness detectors are placed at patient access point to detect blood leakage, then detection capability is improved, but system reliability deteriorates due to misplaced detectors and unpredictable leak paths

Engineering Contradiction:

Improveblood leakage detection capabilityVSAvoiddetection reliability

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The optical sensor serves multiple functions: it monitors blood flow, detects needle dislodgement, and identifies blood leakage simultaneously. This multi-functionality eliminates the need for separate wetness detectors, improving reliability by providing consistent detection regardless of leak path or detector placement.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system continuously monitors optical properties of blood in real-time and provides immediate feedback when changes indicate needle dislodgement or leakage. This continuous feedback mechanism ensures reliable detection without requiring precise pre-positioning of detectors, as the system adapts to changing conditions dynamically.

Inventive Principle:

Principle #23Feedback

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

Methodology Applied

Scientific EffectOptical backscatter: Scattering

Data Source

PatentUS12390571B2Needle dislodgement detection systems and methods

Publication Date: 2025.08.19 FRESENIUS MEDICAL CARE HOLDINGS INC

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.