Dynamic Clot Aspiration Control With Pressure Pulse Feedback
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Solution Overview
Problem
Existing thrombectomy systems face challenges in controlling blood loss and optimizing clot removal during aspiration procedures, particularly when the catheter tip falls out of contact with the thrombus, leading to excessive blood loss and premature termination of the procedure.
Innovation Solution
A vacuum aspiration control system with a sensing unit and controller that monitors flow rate and composition to automatically adjust aspiration modes, including restricted, full, or pulsed aspiration, to minimize blood loss and enhance clot removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If full vacuum aspiration is applied continuously, then clot removal efficiency is improved, but blood loss increases excessively when catheter tip is not in contact with thrombus
Solution Approach 1:
The system continuously monitors flow rate through sensors in the aspiration tubing and provides feedback to the controller. When the catheter tip is not in contact with thrombus, the sensor detects high flow rate of blood-free flow, and the controller automatically reduces or stops vacuum aspiration to prevent excessive blood loss. When clot is detected (restricted flow), the system maintains full vacuum aspiration for effective clot removal.
Solution Approach 2:
The aspiration system dynamically adjusts the vacuum level based on real-time flow conditions rather than maintaining a static full vacuum. The controller modulates the vacuum pump output or adjusts valve positions to vary aspiration strength, transitioning between full vacuum, reduced vacuum, and stopped aspiration modes according to whether clot or blood is being aspirated.
2Loss of substance
If manual control of aspiration is used, then blood loss can be monitored, but procedure efficiency decreases and blood loss control is unreliable
Solution Approach 1:
The system performs self-monitoring and self-adjustment of aspiration levels without requiring continuous manual intervention. The flow sensors automatically detect whether blood or clot is being aspirated, and the controller autonomously adjusts vacuum levels accordingly, eliminating the need for manual monitoring while maintaining reliable blood loss control.
Solution Approach 2:
Automatic feedback control loops continuously monitor aspiration flow characteristics and adjust vacuum levels in real-time. The system compares sensed flow rate against predetermined thresholds and automatically modifies aspiration parameters to optimize both blood loss control and procedure efficiency without manual input.
3Speed
If aspiration vacuum is increased to improve clot removal, then clot removal speed increases, but blood loss increases when catheter is in healthy blood
Solution Approach 1:
The vacuum level is dynamically adjusted based on real-time detection of aspiration content. High vacuum is applied only when clot is detected (restricted flow condition), while low or zero vacuum is applied when blood is aspirated (unrestricted flow condition), thereby achieving fast clot removal without proportional increase in blood loss.
Solution Approach 2:
The system uses flow rate sensors to provide continuous feedback on aspiration content. When the sensor detects high flow rate indicating blood aspiration, the controller reduces vacuum to minimize blood loss. When restricted flow indicating clot aspiration is detected, the controller maintains or increases vacuum to maximize clot removal speed.
4Loss of substance
If aspiration procedure is terminated early due to excessive blood loss, then blood loss is limited, but clot removal completeness decreases
Solution Approach 1:
Continuous flow monitoring provides real-time feedback that distinguishes between blood aspiration and clot aspiration. The system accumulates clot removal over extended procedure time by maintaining full vacuum only during clot aspiration phases, while reducing vacuum during blood phases, thereby achieving complete clot removal without excessive cumulative blood loss.
Solution Approach 2:
The aspiration process occurs in periodic cycles of full vacuum (during clot aspiration) and reduced/zero vacuum (during blood aspiration). This periodic modulation allows the procedure to continue longer with alternating phases of intensive clot removal and blood loss prevention, ultimately achieving complete clot removal with controlled total blood loss.
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 prolongs procedures by reducing blood loss and ensuring more complete clot removal by dynamically adjusting aspiration based on flow conditions, allowing for safer and more efficient thrombectomy.
Implementation Method 1
a vacuum pump which operates off line voltage... Blood and clot are drawn into a collection canister from an aspiration tube which is connected to a reperfusion catheter... by a partial vacuum which is provided by a vacuum connector
Implementation Method 2
a flow sensor located on the connecting tube to detect flow rate within the connecting tube and to determine whether unrestricted flow, restricted flow, or clog is present
Implementation Method 3
a controller to automatically open and close the valve in response to the signal from the flow sensor
Data Source
AI summary
A dynamic aspiration system includes a connecting tube, a vacuum source, a pressure source, an aspiration catheter, a first controllable valve to control a level of negative pressure provided by the vacuum source, a second controllable valve to control a level of positive pressure provided by the pressure source, pressure sensors, and a controller. The controller modulates the controllable valves to generate pressure pulses, determines, for each of the pressure pulses, a degree of success corresponding to a change in a flow in the aspiration catheter or the connecting tube responsive to the pressure pulse, identifies one or more first pressure pulses determined to have the highest degrees of success, and modulates the controllable valves to generate the first pressure pulses in one or more pressure pulse cycles.