Infusion Pump Cartridge Presence Detection via PWM Threshold

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Solution Overview

Problem

Current insulin infusion pumps face issues with inaccurate delivery due to the potential detachment or improper attachment of interchangeable infusion cartridges, leading to inconsistencies in medication administration.

Innovation Solution

A system and method for detecting the presence or absence of an infusion cartridge using pulse width modulation (PWM) commands, where a threshold value is set and compared during pumping operations, generating an alarm if the operational PWM command drops below the threshold, indicating a missing cartridge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If an interchangeable infusion cartridge is used in the infusion pump, then the adaptability and ease of operation are improved, but the reliability deteriorates due to potential detachment or improper attachment

Engineering Contradiction:

Improveinterchangeable cartridge compatibilityVSAvoidcartridge attachment stability

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The system continuously monitors motor current draw and compares it against expected ranges to detect cartridge presence and proper attachment. This feedback mechanism allows the pump to verify cartridge installation and alert users to detachment or improper attachment, resolving the reliability issue while maintaining interchangeability

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent replaces mechanical attachment verification with an electrical monitoring system that measures motor current characteristics. This substitution allows for automated detection of cartridge presence and proper installation without adding mechanical complexity to the attachment mechanism itself

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If continuous monitoring of cartridge presence is implemented, then the reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvecartridge presence detectionVSAvoidmonitoring system complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The system uses the motor's own electrical characteristics (current draw) as the sensing mechanism. The existing motor control circuitry serves dual purposes: driving the motor and detecting cartridge presence. This self-service approach eliminates the need for separate sensors or complex monitoring hardware

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The motor control system performs multiple functions: it drives the infusion pump motor and simultaneously monitors cartridge presence through current measurement. This multi-functionality reduces overall system complexity by eliminating dedicated monitoring components

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS20240148966A1System and method for detecting presence of an infusion cartridge in an infusion pump

Publication Date: 2024.05.09 TANDEM DIABETES CARE INC

AI summary

Infusion devices, systems, and methods can detect a presence or absence of an infusion cartridge in an infusion pump. Embodiments may include a loading sequence, recording loading pulse width modulation (PWM) commands applied to an infusion pump motor during the loading sequence, setting a value of threshold PWM commands based on the commands applied during the loading sequence and comparing values of operational PWM commands applied during pumping operations to the value of the threshold PWM commands. If the value of the operational PWM commands drops below the threshold by a predetermined amount, a missing infusion cartridge warning may be generated.