Infusion Pump Occlusion Management via Model-Based Reverse Displacement
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Solution Overview
Problem
Existing infusion delivery devices face challenges in managing pressure during occlusions, which can lead to either overdosing or underdosing of medicament, and potentially extract bodily fluids due to unpredictable pressure changes.
Innovation Solution
The infusion delivery device incorporates a controller that determines occlusions and provides a control signal to move the dispensing member in a reverse direction by a model-based displacement distance, taking into account parameters such as the dispensing member's position, reservoir temperature, medicament temperature, pressure, and compressibility to level the pressure within the reservoir.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the controller moves the dispensing member in a reverse direction by a fixed displacement distance upon determining an occlusion, then the pressure within the reservoir is decreased to lower the risk of overdosing, but the displacement distance may be too large creating negative pressure that draws liquid medicament back into the reservoir causing underdosing
Solution Approach 1:
The system transitions from a fixed reverse displacement distance to a dynamic, adaptive reverse displacement distance that is calculated based on real-time system state parameters including compressibility, temperature, and pressure. This allows the reverse movement to be optimized for each specific occlusion event, preventing both overdosing (by adequately reducing pressure) and underdosing (by avoiding excessive negative pressure).
Solution Approach 2:
The system changes the key parameter of displacement distance from a fixed value to a variable value that depends on multiple physical parameters (compressibility, temperature, pressure). By continuously monitoring these parameters and adjusting the reverse displacement distance accordingly, the system achieves precise pressure control that adapts to different operating conditions and occlusion scenarios.
2Reliability
If the controller continues to advance the dispensing member upon occlusion detection, then the pressure within the reservoir increases, but this may cause unintended overdosing if the occlusion is suddenly resolved
Solution Approach 1:
The system implements a feedback mechanism where the controller continuously monitors pressure, temperature, and compressibility parameters during occlusion events. Based on this feedback, the controller dynamically adjusts the reverse displacement distance to achieve the optimal pressure reduction, ensuring that pressure is lowered sufficiently to prevent overdosing without creating excessive negative pressure that could cause underdosing.
3Object-affected harmful factors
If the displacement distance is increased to ensure pressure reduction, then overdosing risk is lowered, but liquid medicament may be drawn back into the reservoir causing underdosing and extraction of bodily fluids
Solution Approach 1:
The system utilizes changes in physical parameters (compressibility, temperature, pressure) to dynamically determine the optimal reverse displacement distance. By incorporating compressibility measurements, the system can predict how much pressure reduction is needed and calculate the precise displacement distance required, avoiding both insufficient pressure reduction (overdosing risk) and excessive pressure reduction (underdosing and fluid extraction risk).
Data Source
AI summary
An infusion delivery device has a reservoir for containing a liquid medicament, a dispensing member moveably arranged within the reservoir for dispensing liquid medicament out of the reservoir through an outlet of the reservoir, an actuation member for moving the dispensing member within the reservoir, and a controller for controlling the movement of the dispensing member within the reservoir by the actuation member. The controller determines an occlusion hindering the dispensing of liquid medicament out of the reservoir and provides a control signal to the actuation member upon determining the occlusion, to move the dispensing member in a reverse direction about a model-based displacement distance.