Infusion Pump Adaptive Filtering for Patient Pressure Control
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Solution Overview
Problem
Existing infusion pumps face challenges in accurately adjusting fluid delivery due to fluctuations in fluid pressure caused by patient movement and pump motor contributions, leading to unintended bolus, under-delivery, and cessation of fluid flow, which are difficult to monitor and require significant device resources.
Innovation Solution
Incorporating an adaptive filter to separate contributors to fluid pressure, such as the pump motor and patient movement, allowing for improved feed-forward control by removing motor-induced noise from pressure signals, thereby enhancing the accuracy and reliability of fluid delivery adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If direct flow-rate measurements are used to measure fluid pressure, then measurement capability is provided, but measurement precision deteriorates and device resources are significantly consumed
Solution Approach 1:
The patent introduces an intermediary computational model that estimates motor-induced pressure changes based on motor operating parameters (current, voltage, speed) rather than directly measuring total pressure and attempting to extract patient pressure components. This intermediary approach uses the known relationship between motor operation and pressure generation to calculate motor pressure contributions, which are then subtracted from total pressure measurements to yield accurate patient pressure readings with reduced computational burden
Solution Approach 2:
The patent replaces complex mechanical pressure sensing and signal processing systems with a computational approach that uses motor electrical parameters to model and subtract motor-induced pressure effects. Instead of relying on sophisticated pressure sensors and complex signal filtering algorithms to isolate patient pressure from motor pressure, the system substitutes a mathematical model based on motor current, voltage, and speed measurements to achieve the same separation with reduced resource consumption
2Measurement precision
If motor pressure is not removed from fluid pressure measurements, then device complexity is reduced, but measurement precision deteriorates leading to unintended bolus and under-delivery
Solution Approach 1:
The patent extracts the motor pressure component from the total fluid pressure measurement by calculating it from motor operating parameters (current, voltage, speed) and subtracting it from the total pressure. This extraction process isolates the patient pressure component, enabling accurate determination of patient-related pressure changes without requiring complex multi-sensor systems or advanced signal processing algorithms
Solution Approach 2:
The patent changes the parameters used for pressure analysis from direct pressure sensor readings to motor electrical parameters (current, voltage, speed). By monitoring and modeling pressure based on these electrical parameters, the system can dynamically calculate motor-induced pressure effects and remove them from total pressure measurements, simplifying the overall measurement system while improving precision
3Measurement precision
If sophisticated sensors and detection methods are used to measure fluid pressure, then measurement capability is improved, but device resources are significantly consumed especially for low flow rates
Solution Approach 1:
The patent makes the motor serve multiple functions: it not only delivers fluid to the patient but also acts as a pressure sensor through its electrical parameters. By monitoring motor current, voltage, and speed, the system simultaneously controls fluid delivery and measures pressure conditions, eliminating the need for separate sophisticated pressure sensing systems and reducing overall device resource requirements
Data Source
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AI summary
A method includes measuring a fluid pressure of fluid in a fluid supply line of an infusion pump. The fluid pressure includes a motor pressure and a patient pressure. The method also includes determining the patient pressure. The determining includes removing, by an adaptive filter, to remove the motor pressure from the measured fluid pressure. The removing includes generating a predicted motor pressure based on the current of the motor, generating an error signal based on a comparison between the predicted motor pressure and the measured fluid pressure, and removing the motor pressure from the measured fluid pressure when an error value indicative of the error signal is less than an error threshold. The method also includes adjusting, based on the patient pressure, a setting of the infusion pump. Related methods and articles of manufacture, including apparatuses and computer program products, are also disclosed.