Intraluminal Pressure Prediction for Pump Flow Control
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Solution Overview
Problem
Fluid management systems in flexible ureteroscopy and other endoscopic procedures face challenges in controlling intraluminal pressure (ILP) due to continued fluid flow after the pump is disabled, leading to ILP exceeding threshold values, and delays in sensor measurements affecting pump operation parameters.
Innovation Solution
A fluid management system with a controller that predicts future intraluminal pressure by solving time-dependent differential equations and adjusts pump operation parameters, such as RPM and flow direction, to prevent ILP from exceeding thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is disabled to stop fluid delivery, then the pump operation is stopped, but fluid continues to flow due to tubing capacity causing ILP to exceed threshold
Solution Approach 1:
The system predicts future ILP values based on current pump state and tubing characteristics before the actual pressure exceeds the threshold. By calculating the time constant of the tubing and projecting forward, the controller proactively adjusts pump operation to prevent threshold violation rather than reacting after the problem occurs.
Solution Approach 2:
The system continuously monitors actual ILP measurements from the procedural device and compares them against predicted values. This feedback loop allows the controller to adjust pump operation dynamically, using both real-time sensor data and predictive models to maintain accurate pressure control despite the lag introduced by tubing capacity.
2Productivity
If the pump operates at elevated boost speed to clear visual field, then fluid flow rate increases, but ILP may exceed threshold due to continued flow after pump stops
Solution Approach 1:
Before initiating boost mode operation, the controller calculates the time constant of the fluid tubing and predicts how long fluid will continue to flow after pump cessation. This preliminary calculation allows the system to set appropriate pump stop timing that accounts for the lingering flow effect, preventing ILP threshold violation even during high-productivity boost operations.
Solution Approach 2:
The system dynamically adjusts pump operation parameters based on real-time conditions. During boost mode, the controller continuously monitors ILP and adjusts pump speed or stop timing based on the predicted decay curve of fluid flow, allowing flexible optimization of both productivity and safety depending on procedural needs.
3Ease of operation
If the pump stops immediately when threshold is approached, then pump operation is simplified, but fluid continues to flow causing ILP to exceed threshold
Solution Approach 1:
Instead of simply stopping the pump when threshold is approached, the system performs a preliminary prediction of future ILP values based on current tubing fill state and flow characteristics. This allows the controller to determine the optimal stop timing that accounts for the time constant of the tubing, maintaining simple operation while preventing threshold violation through informed decision-making.
Solution Approach 2:
The system uses the tubing's own physical characteristics (capacity, length, diameter) to automatically determine how long fluid will continue to flow after pump stop. By embedding this knowledge in the controller, the system self-adjusts pump operation without requiring complex external intervention, maintaining ease of operation while ensuring reliable threshold control.
Data Source
AI summary
The disclosure provides devices, systems, and methods to predict an intraluminal pressure (ILP) of a lumen, at a future time, in which an endoscopic medical device is inserted and coupled to a fluid management system (FMS) to provide fluid flow to the lumen. The disclosure provides a controller for the FMS to predict ILP of the lumen and to modulate operating parameters (e.g., speed, on/off, parasitic timing, flow direction, etc.) of a pump of the FMS based on the predicted ILP and an ILP threshold value to prevent or mitigate the risk that the ILP will exceed the ILP threshold value.