Angiography Injector Fluid Paths for Air Bubble Isolation
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Solution Overview
Problem
Existing fluid injector systems face challenges in preventing the delivery of air bubbles to patients during high-pressure medical fluid injections, particularly in angiography procedures, due to the compressibility of air and the speed of fluid flow, which can result in significant volume expansion and potential injection of air even after actuation is halted.
Innovation Solution
A fluid injector system with an upstream air detector and a downstream automated shutoff valve is employed, utilizing a zig-zag tubing configuration to delay and trap air bubbles, combined with a controller that actuates the shutoff valve to prevent air from reaching the patient by lengthening the fluid path and increasing volume, ensuring timely closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high pressure injection is used for angiography procedures, then fluid delivery speed and effectiveness are improved, but the risk of air bubble injection and patient harm increases
Solution Approach 1:
The system performs preliminary air detection upstream in the fluid path before high-pressure injection begins. The air detector is positioned to identify air bubbles before they can be accelerated by high-pressure flow, allowing preventive shutdown before the harmful effect can occur.
Solution Approach 2:
The patent introduces an intermediary detection and control system between the fluid source and the patient. The air detector acts as an intermediary sensor that monitors the fluid path, and the controller serves as an intermediary control element that mediates between detection and shutdown actions to prevent air injection.
2Reliability
If air detection and shutoff systems are added to prevent air injection, then patient safety is improved, but system complexity increases
Solution Approach 1:
The patent extracts the air detection and control functions into separate, dedicated components (air detector and controller) that are integrated into the existing injector system. This modular approach allows safety functionality to be added without completely redesigning the entire injection system, thereby limiting the increase in overall complexity.
Solution Approach 2:
The system implements a feedback loop where the air detector continuously monitors the fluid path and provides real-time information to the controller. When air is detected, the controller automatically triggers shutdown, creating a closed-loop safety system that responds dynamically to conditions without requiring complex manual intervention systems.
3Reliability
If the fluid path is lengthened to trap air bubbles, then air isolation effectiveness is improved, but injection time and productivity are reduced
Solution Approach 1:
The patent converts the harmful presence of air bubbles into a beneficial detection opportunity. By positioning the air detector upstream, the system uses the air bubbles' natural presence in the fluid path as a detectable signal, transforming a harmful element into the basis for an effective safety mechanism that doesn't require additional trapping time.
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
The system effectively prevents air bubbles from entering the patient's vasculature by detecting and isolating them before reaching the patient, ensuring accurate and safe high-pressure fluid delivery.
Implementation Method 1
at least one air detector upstream in the fluid path from the patient
Implementation Method 2
an automated remote shutoff valve downstream from the injection site... the actuator element actuates the remote shutoff valve from the delivery position to the stop position
Implementation Method 3
utilizing a zig-zag tubing configuration to delay and trap air bubbles, combined with a controller that actuates the shutoff valve
Implementation Method 4
the compressibility of gas relative to liquids compresses the volume of air bubbles in the fluid line compared to the same molar amount of air at lower pressures
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
A fluid injector system includes at least one syringe configured for injecting medical fluid and a fluid path assembly in fluid communication with the at least one syringe, the fluid path assembly including at least one air detection region. The system includes an air detector configured to detect one or more air bubbles in a fluid path associated with the air detection region, at least one shutoff valve at a distal end of the fluid path assembly, and at least one processor programmed or configured to actuate the shutoff valve in response to the air detector detecting the one or more air bubbles in the fluid path associated with the air detection region to prevent fluid flow out of the fluid path assembly. The fluid path assembly has a length greater than a distance that an air bubble can travel or expand during an actuation time of the shutoff valve.