Negative Pressure Wound Therapy Pump Control Algorithm

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Solution Overview

Problem

Current negative pressure wound therapy systems face inaccuracies in measuring pressure at the wound site due to pressure gradients through the fluid system, leading to discrepancies between intended and applied pressure, which complicates treatment and increases costs with additional sensors and monitoring tubes.

Innovation Solution

A method for estimating negative pressure at the wound site by determining a modification value based on pump speed and pressure sensor readings, allowing for accurate pressure control without additional sensors or fluid systems, using a constant to adjust for pressure drops between the pump and the wound.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a pressure sensor is located near the pressure source (pump), then the device complexity is reduced, but the measurement precision of pressure at the wound site deteriorates due to pressure gradients through the fluid system

Engineering Contradiction:
Improvedevice complexityVSAvoidpressure measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical approach of physically locating a pressure sensor at the wound site with a computational method. A correction algorithm uses the known pressure gradient characteristics of the fluid system to calculate and subtract the pressure drop from the pump-side measurement, yielding an estimated wound site pressure without requiring additional mechanical components at the wound location.

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

Solution Approach 2:

The patent introduces a computational intermediary (correction algorithm) that mediates between the pump-side pressure measurement and the desired wound site pressure information. This algorithm acts as a virtual intermediary that translates the pressure reading from one location into an accurate representation of pressure at the remote wound site, avoiding the need for physical intermediary components.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If additional pressure monitoring tubes and sensors are added to measure accurate pressure at the wound site, then the measurement precision improves, but the device complexity and costs increase

Engineering Contradiction:
Improvepressure measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system performs self-correction by utilizing its existing components (pump-side pressure sensor and knowledge of fluid system characteristics) to generate accurate wound site pressure information. The correction algorithm enables the system to serve its own measurement needs without requiring external additional sensors or monitoring tubes, thereby maintaining measurement precision while avoiding increased device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The existing pressure sensor near the pump serves multiple functions: it directly monitors pump performance and, through the correction algorithm, simultaneously provides accurate wound site pressure measurement. This multi-functionality eliminates the need for dedicated wound site pressure sensors, reducing device complexity while maintaining measurement precision.

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

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 method ensures accurate and reproducible pressure application during negative pressure wound therapy, reducing complexity and costs by maintaining target pressures within the desired range of 10-150 mmHg, regardless of wound size or exudate amounts, and operates robustly without additional components.

Implementation Method 1

determining a negative pressure value by means of a pressure sensor, wherein the pressure sensor is located in a fluid path between the wound site and an electrical pump

Methodology Applied
Scientific EffectPressure sensor measurement:

Implementation Method 2

an electrical pump (5) for generating a negative pressure

Methodology Applied
Scientific EffectNegative pressure generation: Pressure Drop

Data Source

PatentEP3187203B2Methods and devices for controlling negative pressure at a wound site
Publication Date: 2022.08.24 PAUL HARTMANN AG
  • EP3187203B2 patent drawingFigure 1
  • EP3187203B2 patent drawingFigure 2a~2b
  • EP3187203B2 patent drawingFigure 2c~2e

AI summary

The invention relates to a method for estimating a negative pressure at a wound site during a negative pressure wound therapy. The method comprises the steps of determining a negative pressure value by means of a pressure sensor, determining a pump speed associated with the electrical pump, multiplying the pump speed by a constant to obtain a modification value, and combining said modification value with the negative pressure value determined by means of the pressure sensor to obtain a modified negative pressure value. Said modified negative pressure value corresponds to the estimated negative pressure present at the wound site. The invention further relates to a negative pressure wound therapy system adapted to execute said method of estimating a negative pressure at a wound site.