Infusion Apparatus Automatic Occlusion Threshold Calculation

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Solution Overview

Problem

Current infusion devices rely on caregiver experience and 'rule of thumb' methods to set occlusion alarm pressure thresholds, often leading to false alarms or missed occlusions due to lack of precise parameters like catheter and tubing resistance, fluid viscosity, which can disrupt medication delivery and pose patient risks.

Innovation Solution

A system and method for automatically calculating occlusion pressure thresholds using a processor that receives infusion parameters, calculates flow resistance, and sets a pressure threshold based on these parameters, including dynamic measurements and user input, to provide accurate alerts during fluid infusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If caregivers manually set pressure thresholds using experience or rule of thumb, then the device complexity is reduced and ease of operation is improved, but the measurement precision and reliability of occlusion detection deteriorate

Engineering Contradiction:
Improveease of setting pressure thresholdVSAvoidprecision of occlusion pressure threshold
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The system automatically calculates the occlusion pressure threshold using measured parameters (flow rate, resistance, compliance) without requiring caregiver input or experience. The processor performs the calculation based on the formula P_occlusion = P_working + P_noise_margin, where P_working = Q × R and P_noise_margin = 0.05 × (P_max - P_min). This self-service approach eliminates manual setting errors while maintaining ease of operation.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the manual caregiver judgment process with an automated computational system. The processor measures physical parameters (flow rate Q, resistance R, compliance C) and computes the pressure threshold using mathematical relationships, substituting human experience-based estimation with precise mechanical measurement and calculation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If the pressure threshold is set too low to detect occlusions quickly, then the reliability of occlusion detection is improved, but false alarms increase reducing productivity

Engineering Contradiction:
Improvereliability of occlusion detectionVSAvoidproductivity of medication delivery
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system continuously monitors pressure during infusion and compares it against the dynamically calculated threshold. The noise margin (5% of pressure range) provides a feedback mechanism that adjusts the threshold to account for normal pressure variations, reducing false alarms while maintaining reliable occlusion detection. The system adapts to the specific infusion conditions rather than using fixed thresholds.

Inventive Principle:
Principle #23Feedback

3Productivity

If the pressure threshold is set too high to avoid false alarms, then the productivity is improved, but the reliability of occlusion detection deteriorates

Engineering Contradiction:
Improveproductivity of medication deliveryVSAvoidreliability of occlusion detection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The system changes the pressure threshold parameter dynamically based on measured infusion conditions (flow rate, resistance, compliance, pressure range). Rather than using a fixed high threshold that might miss occlusions, the threshold adapts to each specific infusion scenario, ensuring both high productivity and reliable detection.

Inventive Principle:
Principle #35Parameter changes

4Measurement precision

If automated calculation of pressure threshold is implemented, then the measurement precision and reliability are improved, but the device complexity increases

Engineering Contradiction:
Improveprecision of occlusion pressure thresholdVSAvoidcomplexity of pressure threshold setting
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The processor performs multiple functions: measuring flow rate, measuring pressure, calculating resistance, calculating compliance, and computing the occlusion pressure threshold. This multi-functionality consolidates what would otherwise require separate devices or manual steps into a single integrated system, reducing overall complexity despite the advanced calculations performed.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP2704766B1Fluid infusion method and apparatus
Publication Date: 2024.10.16 CAREFUSION 303 INC
  • EP2704766B1 patent drawingFigure 1
  • EP2704766B1 patent drawingFigure 2
  • EP2704766B1 patent drawingFigure 3A

AI summary

A method of infusing a fluid includes receiving values of one or more infusion parameters for an infusion of a fluid, Based on the received infusion parameter values, an occlusion pressure threshold for the infusion of the fluid is automatically calculated. During the infusion, a fluid pressure value is sensed. An indication is provided responsive to whether a value of the sensed fluid pressure is greater than the occlusion pressure threshold.