Ambulatory Infusion Supervision Device with Upstream Gas Detection
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Solution Overview
Problem
Ambulatory infusion systems face challenges in accurately detecting liquid drug flow due to occlusions and distinguishing between no flow and gas bubbles, leading to delayed detection and false alarms, which is particularly problematic for low flow rates and small drug administrations.
Innovation Solution
A supervision device is introduced that includes both a flow detector and a gas detector, with the gas detector positioned upstream of the flow detector, allowing the processing unit to differentiate between no liquid flow and gas bubbles by analyzing signals from both detectors, thereby reducing false alarms and improving detection accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermal flow sensors are used to directly measure liquid drug flow, then detection speed and accuracy are improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces complex thermal flow sensors with a simpler optical flow detector that uses light transmission through the tubing to detect flow presence and gas bubbles, reducing device complexity while maintaining detection accuracy
Solution Approach 2:
The patent introduces an intermediary optical detection system that measures flow indirectly through light transmission properties of the fluid, avoiding the need for direct thermal contact with the liquid drug and simplifying the sensor design
2Device complexity
If indirect occlusion detection methods are used, then device complexity is reduced, but detection time increases significantly
Solution Approach 1:
The patent replaces indirect mechanical reaction force measurement with direct optical flow detection, enabling immediate occlusion detection without significant time delay while keeping the system relatively simple
Solution Approach 2:
The patent implements continuous optical monitoring of flow through the tubing, allowing real-time detection of occlusions as they occur rather than relying on delayed reaction force changes, thus eliminating detection delays
3Measurement precision
If thermal flow sensors are used for continuous monitoring, then detection accuracy is improved, but false alarms increase due to sensitivity to minor flow variations
Solution Approach 1:
The patent changes the detection parameter from thermal flow rate to optical light transmission properties, which provides better discrimination between normal flow variations and actual occlusions or gas bubbles, reducing false alarms while maintaining accuracy
Solution Approach 2:
The patent uses optical properties as an intermediary measurement that is less sensitive to minor flow variations compared to thermal methods, providing more reliable detection that distinguishes between normal operation and actual problems
4Object-affected harmful factors
If disposable sterile flow sensors are used, then infection risk is reduced, but manufacturing cost and handling complexity increase
Solution Approach 1:
The patent uses optical detection through the existing disposable tubing as an intermediary, eliminating the need for separate sterile flow sensors while maintaining infection control through the disposable nature of the tubing and sensor integration
Solution Approach 2:
The patent makes the existing disposable tubing serve multiple functions: fluid transport and optical flow detection medium, eliminating the need for separate sterile sensors and simplifying manufacturing and handling
5Measurement precision
If flow detection is performed at low flow rates, then measurement accuracy is improved, but detection sensitivity to gas bubbles and occlusions decreases
Solution Approach 1:
The patent replaces thermal flow measurement with optical light transmission measurement, which maintains high sensitivity and accuracy even at very low flow rates and provides excellent discrimination between liquid flow, gas bubbles, and occlusions regardless of flow rate
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
This solution enables timely detection of occlusions and accurate differentiation between no flow and gas bubbles, reducing delays and false alarms, thus ensuring reliable liquid drug administration in ambulatory infusion systems.
Implementation Method 1
thermal energy that is emitted from the heating element is thermally conducted by the liquid to both temperature sensors
Implementation Method 2
the thermal energy is largely transported downstream, resulting in the downstream temperature sensor measuring a higher temperature
Implementation Method 3
an optical gas detector... arranged for operatively coupling with the flow channel and generating a gas detector signal in dependence of whether liquid or gas is present
Data Source
AI summary
Disclosed is a supervision device (9) for supervising liquid drug flow in a flow channel (20). The supervision device (9) includes a flow detector (1), arranged for operatively coupling with the flow channel (20) and generating a flow detector signal in dependence of a flow in the flow channel (20) at a flow detection location. The supervision device (9) further includes a gas detector (8), arranged for operatively coupling with the flow channel (20) and generating a gas detector signal in dependence of whether liquid drug or gas is present in the flow channel (20) at a gas detection location at a distance upstream from the flow detection location. The supervision device (9) further includes a processing unit (90) in operative coupling with the flow detector (1) and the gas detector (8), wherein the processing unit (90) is configured to determine, based on the gas detector signal, whether non-flowing liquid drug is present at the flow detection location or a gas bubble passes the flow detector if the flow detector signal does not indicate a liquid drug flow.