Infusion Pump Pulse Frequency Compensation for Tubing Degradation
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Solution Overview
Problem
Infusion therapy systems face accuracy issues due to tubing degradation over time, leading to under-infusion and increased costs from frequent administration set changes, especially with PVC-based systems, while silicone-based systems pose sterility concerns and manufacturing complexities.
Innovation Solution
Implementing a volume-based flow rate compensation technique in infusion pumps, where the controller adjusts pulse frequency based on the volume of fluid infused, using a Tubing Degradation Function to correlate historical performance and maintain accuracy without additional hardware or manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If PVC-based administration sets are used for long-duration infusions, then cost is reduced and ease of manufacture is improved, but flow rate accuracy deteriorates due to tubing degradation
Solution Approach 1:
The system dynamically changes the pulse frequency parameter based on the volume of fluid infused. As the tubing degrades and resiliency decreases, the controller automatically adjusts the pulse frequency to compensate, maintaining accurate flow rate delivery throughout the infusion duration without requiring frequent administration set changes
Solution Approach 2:
The system implements a feedback mechanism where the controller continuously monitors the volume of fluid infused and uses this information to adjust the pulse frequency. The Tubing Degradation Function processes historical performance data to determine the appropriate frequency adjustment, creating a closed-loop control system that maintains accuracy despite tubing degradation
2Measurement precision
If administration sets are changed frequently to maintain accuracy, then flow rate accuracy is improved, but productivity decreases and loss of time increases
Solution Approach 1:
The system enables continuous accurate infusion delivery without interruption for administration set changes. By dynamically adjusting pulse frequency throughout the infusion, the system maintains accuracy over extended periods, eliminating the need to stop therapy for set changes and thereby improving productivity and reducing loss of time
3Measurement precision
If pulse frequency is increased to compensate for tubing degradation, then flow rate accuracy is improved, but use of energy increases
Solution Approach 1:
The system dynamically adjusts pulse frequency based on actual tubing performance rather than using a fixed high frequency. The controller modifies the frequency in real-time according to the volume infused and degradation characteristics, optimizing energy usage by applying only the necessary compensation rather than continuously operating at maximum frequency
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 approach significantly reduces errors in fluid delivery, allowing longer use of PVC-based administration sets, minimizing interruptions and costs, while ensuring consistent flow rate accuracy across various infusion rates without increasing pump costs or complexity.
Implementation Method 1
an active force is applied to the tubing by the pump mechanism to compress the tubing and move fluid downstream
Implementation Method 2
the pumping mechanism releases the tubing, allowing it to fill again. However, this process passively depends on the resiliency of the tubing to spring back to its full inner diameter
Data Source
AI summary
An infusion pump for pumping fluid through an administrative set at a desired flow rate over a specified duration, and includes a pumping mechanism for releasably receiving and for exerting a pulsing force on the administrative set, thus pressurizing a portion of the set for creating a flow of fluid from a set outlet. A controller is connected to and is configured for operating the pumping mechanism, the controller determines a pulse frequency based on a volume of fluid infused over a portion of the specified duration and the desired flow rate, outputs a control signal to the pumping mechanism for operating the pumping mechanism based on the determined pulse frequency, determines a first pulse frequency based on the desired flow rate; and adjusts the first pulse frequency based on the volume of fluid infused to provide a second pulse frequency being different from the first pulse frequency.