Bioimpedance Correction Factor for Amputee Body Composition

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Solution Overview

Problem

Current methods for determining body composition using bioimpedance measurements are limited in their ability to accurately assess patients with amputations, as they often require adapted patient models or segmental measurements, which are not practical for whole-body analysis in amputees.

Innovation Solution

A method and device that utilize a whole-body bioimpedance measurement approach, where the original body model is used without requiring adapted patient models, by applying a correction factor to account for missing limbs or extremities, allowing for the determination of corrected volume compartments such as lean tissue, adipose tissue, hydration volume, and extracellular water.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If adapted patient models or segmental measurements are used to account for amputations, then measurement precision is improved, but device complexity and ease of operation deteriorate

Engineering Contradiction:
Improvebody composition measurement accuracyVSAvoidmodel adaptation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by using correction factors that modify the bioimpedance measurement results to account for amputated limbs. Instead of creating complex adapted models, the system adjusts the output parameters (volume compartments, body composition) using pre-determined correction factors based on the type and extent of amputation, thereby maintaining measurement precision without increasing model complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent uses copying by referring to standard body composition models and applying correction factors to replicate accurate results for amputee patients. The system copies the standard measurement protocol and adjusts it through mathematical correction factors rather than creating entirely new measurement models, simplifying the approach while maintaining accuracy

Inventive Principle:
Principle #26Copying

2Measurement precision

If segmental measurements are used to examine amputation influence, then measurement precision is improved, but ease of operation deteriorates

Engineering Contradiction:
Improvebody composition measurement accuracyVSAvoidmeasurement procedure simplicity
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The patent applies universality by creating a single whole-body bioimpedance measurement system that can accurately assess amputee patients without requiring separate segmental measurements. The correction factor approach allows the same measurement protocol to serve both intact and amputee patients, eliminating the need for complex multi-segment procedures while maintaining precision

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

3Ease of operation

If whole-body measurement is performed on amputees using original body model, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvemeasurement procedure simplicityVSAvoidbody composition measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent applies feedback by using correction factors that are determined based on the patient's specific amputation status. The system incorporates feedback about the amputation (type, location, extent) to adjust the measurement results, ensuring that the simplicity of the whole-body measurement approach does not compromise precision for amputee patients

Inventive Principle:
Principle #23Feedback

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

Enables simple and individualized determination of body composition in amputee patients using bioimpedance measurements, allowing for accurate assessment of hydration and nutritional status without the need for complex adaptations, thereby improving clinical monitoring and management of fluid status in dialysis patients.

Implementation Method 1

A low level alternating current is applied across two or more electrodes attached to the patient and the corresponding electrical potential difference is measured

Methodology Applied
Scientific EffectBioimpedance measurement: Electrical Resistance

Data Source

PatentEP2348984B1Method for determining a corrected volume compartment of an amputated patient, device for carrying out the method and computer program product
Publication Date: 2020.04.29 FRESENIUS MEDICAL CARE DEUTSCHLAND GMBH
  • EP2348984B1 patent drawingFigure 1~2(d)
  • EP2348984B1 patent drawingFigure 3(a)~4
  • EP2348984B1 patent drawingFigure 5

AI summary

The invention relates to the field of monitoring the hydration and/or nutritional state of a patient using bioimpedance measurement values. The object of the invention is to also be able to easily and individually determine the body composition of an amputee patient using such measurements. The invention is based on the observation that volume compartments can also be determined for amputee patients using bioimpedance measurements if the body models previously used and proven for patients without amputations are employed. Solely the determination of a factor characteristic of the amputation, which can be determined by way of comparison measurements in advance, is required. In certain exceptional, multi-amputation situations, it may be advisable to allow additional parameters to be incorporated for the sake of increased accuracy. The existing body models can then also continue to be used for such cases.