Needle Detachment Detection via Pulsation Frequency Analysis
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Solution Overview
Problem
Current systems for monitoring needle detachment in extracorporeal blood circuits are complex, costly, and struggle to differentiate between actual detachment and other non-alarming events such as patient movement or variations in blood pump velocity.
Innovation Solution
A method and apparatus that monitor the power spectrum of vascular pulsations near the needle, using a sensor to detect the presence or absence of pulsations induced by a peristaltic pump, allowing for discrimination between detachment and other events through frequency analysis and signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If complex monitoring systems with multiple sensors are used to detect needle detachment, then detection reliability is improved, but device complexity and cost increase
Solution Approach 1:
The invention extracts and monitors only the specific frequency component related to blood pump pulsations from the pressure signal, rather than using multiple sensors to detect all possible detachment indicators. By focusing on the characteristic frequency signature of the blood pump, the system achieves reliable detachment detection with a single pressure sensor and frequency analysis algorithm.
Solution Approach 2:
The invention replaces complex mechanical/multiple-sensor detection systems with a signal processing approach. Instead of using multiple physical sensors to detect detachment, the system uses frequency analysis of pressure signals to identify the characteristic pulsation pattern, substituting mechanical complexity with computational analysis.
2Measurement precision
If multiple sensors and complex algorithms are used to monitor vascular access, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The invention changes the parameter being monitored from absolute pressure values or multiple physical parameters to the frequency characteristic of pressure variations. By analyzing the frequency spectrum of pressure signals and identifying the presence or absence of blood pump-related frequency components, the system achieves precise detachment detection through parameter transformation rather than increased sensor complexity.
3Difficulty of detecting and measuring
If pressure monitoring systems are used to detect needle detachment, then detection capability is improved, but difficulty in differentiating detachment from other events increases
Solution Approach 1:
The invention exploits the periodic nature of blood pump operation and its characteristic frequency signature. By monitoring whether pressure signals contain the expected periodic frequency components associated with blood pump pulsations, the system can distinguish between normal operation (periodic pulsations present) and detachment (periodic pulsations absent), preventing false alarms from non-periodic events like patient movement.
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 reliable, economical, and timely detection of needle detachment, distinguishing it from other non-alarming conditions, thereby ensuring safe and effective operation of extracorporeal blood circuits.
Implementation Method 1
a sensor (6) configured for emitting a signal indicating the perturbations which are induced in the transport system (2) by the generator (5) and which are transmitted into the body (4) via the needle (3)
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An apparatus for monitoring a vascular access comprises a dialysis circuit having a venous needle (18) and a blood pump (14) of a peristaltic type which generates oscillatory perturbations in the circuit. An optical sensor (19), arranged on a patient's body by the venous needle, perceives the perturbations transmitted through the needle and sends a pulsating signal to an analysis device (20), absence of which pulsating signal provides an indication of a detachment of the needle.