Impedance Pneumography Electrode Insulation for Lung Volume Linearity

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Solution Overview

Problem

Impedance pneumography's clinical applications are limited due to nonlinearity between thoracic impedance change and lung volume change, especially at low lung volumes, which affects the accuracy of pulmonary flow parameter measurement and restricts its use beyond respiratory rate monitoring.

Innovation Solution

The method involves positioning electrodes on the arms and torso to prevent skin contact, using insulation materials like sleeves or shirts to improve linearity, and employing a processor-based apparatus for accurate impedance pneumography measurements, enhancing the ΔZ/ΔV ratio over the complete lung volume range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If electrodes are placed on the arms and torso with insulation material to prevent skin contact, then linearity of lung volume measurement is improved, but device complexity increases

Engineering Contradiction:
Improvelinearity of lung volume measurementVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces insulation material as an intermediary element positioned between the arm and torso to prevent direct skin contact. This mediator ensures that electrical current follows the intended path through the lung tissue, improving measurement linearity while maintaining patient comfort and safety

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different materials and configurations to different regions: conductive electrodes are placed on the arms, while insulation material is strategically positioned at the torso interface. This local differentiation optimizes both signal quality and measurement accuracy without requiring complete redesign of the entire device

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If impedance pneumography is used for pulmonary flow parameter measurement, then measurement capability is improved, but measurement precision deteriorates at low lung volumes

Engineering Contradiction:
Improvemeasurement capabilityVSAvoidmeasurement precision at low lung volumes
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements preliminary positioning of electrodes and insulation material before measurement begins, ensuring optimal current path configuration from the start. This preliminary setup prevents signal degradation that would occur during actual measurement, particularly at low lung volumes where signal margins are minimal

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent modifies the electrical measurement parameters by changing the current path configuration through strategic electrode placement and insulation positioning. This parameter change ensures consistent current flow through the lungs across the entire volume range, improving precision at low volumes without sacrificing versatility

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If skin contact is prevented using insulation material, then measurement accuracy is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidease of operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent integrates the insulation material within the existing device structure, nesting it between the electrode components and the patient's body. This nested configuration eliminates the need for separate insulation application steps, maintaining measurement accuracy while preserving ease of operation through streamlined device architecture

Inventive Principle:
Principle #7Nested doll (Nesting)

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 improves the linearity of lung volume measurements, especially at low volumes, enabling more accurate detection of phenomena and expanding the clinical applicability of impedance pneumography, including pediatric use by ensuring patient comfort and non-invasiveness.

Implementation Method 1

a small high frequency current is passed through a pair of skin electrodes and another pair of electrodes is used to record the generated voltage that is proportional to the impedance (Z)

Methodology Applied
Scientific EffectElectrical impedance: Electrical Resistance

Implementation Method 2

the skin contact between the arm and the torso is prevented by an insulation material configured to be positioned between the arm and the torso

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Data Source

PatentEP2833788B1Measuring lung volume changes by impedance pneumography
Publication Date: 2019.09.18 TIDE MEDICAL
  • EP2833788B1 patent drawingFigure 1~3
  • EP2833788B1 patent drawingFigure 4
  • EP2833788B1 patent drawingFigure 5~6

AI summary

A method, a sensor arrangement, an apparatus and a computer program product for measuring a change in lung volume, comprising measuring a parameter for impedance pneumography by using at least one electrode (11) configured to be in contact with an arm (2) of a human body (1) and at least one electrode (22) configured to be in skin contact with thorax of a human body (1).