Compression Depth Calculation Using Waveform Transformation

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Solution Overview

Problem

Existing methods for calculating compression depth during CPR are inaccurate due to reliance on integration methods that are prone to large errors and do not account for individual variability in chest structure and bone strength.

Innovation Solution

A compression depth calculation system using a measuring apparatus with an acceleration sensor, magnetic or pressure sensor, and a processing unit that creates a second-order differential waveform and calculates compression depth based on a transformation coefficient derived from comparing this waveform with an acceleration waveform, thereby improving accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If integration methods (two-order integration of acceleration or one-order integration of speed) are used to calculate compression depth, then the calculation process is simple, but the accuracy is low due to large margin of error

Engineering Contradiction:
Improvesimplicity of calculation processVSAvoidaccuracy of compression depth
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent introduces a transformation coefficient as an intermediary parameter that bridges the relationship between acceleration sensor data and compression depth. Instead of directly integrating acceleration to get depth, the system uses the transformation coefficient (derived from comparing second-order differential waveform of magnetic sensor data with acceleration waveform) to accurately convert acceleration measurements into compression depth, thereby eliminating the accumulation of integration errors while maintaining calculation feasibility

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the calculation parameter from direct integration of acceleration to a transformation-based approach using a coefficient that accounts for individual variability. By deriving the transformation coefficient from the ratio between second-order differential waveform of magnetic sensor output and acceleration sensor output, the system dynamically adjusts the calculation parameters to match individual chest characteristics, thus improving accuracy without excessive complexity

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If a fixed relationship between compression force and compression depth is assumed, then the calculation is straightforward, but accuracy is poor due to individual variability in chest structure and bone strength

Engineering Contradiction:
Improvesimplicity of calculation modelVSAvoidaccuracy of compression depth
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent transforms the static, fixed relationship model into a dynamic model that adapts to individual characteristics. The transformation coefficient is not a constant but is derived from real-time comparison between magnetic sensor second-order differential waveform and acceleration sensor waveform, allowing the system to dynamically adjust to each individual's chest structure, bone strength, and compression characteristics

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system implements feedback by continuously comparing the second-order differential waveform from the magnetic sensor with the acceleration waveform from the acceleration sensor. This comparison provides feedback that is used to determine the transformation coefficient, ensuring that the calculation model adapts to the actual physical characteristics of the individual being measured, thereby improving accuracy while maintaining operational simplicity

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 precise calculation of compression depth, reducing errors and providing real-time feedback for optimal CPR performance by using a combination of sensors and processing techniques.

Implementation Method 1

an acceleration sensor configured to detect the acceleration of the movement of the compressed portion of the object

Methodology Applied
Scientific EffectAcceleration sensing: Accelerometer

Implementation Method 2

a magnetic sensor or a pressure sensor configured to output information according to the magnitude of compression with respect to the compressed portion of the object

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Implementation Method 3

a magnetic sensor or a pressure sensor configured to output information according to the magnitude of compression with respect to the compressed portion of the object

Methodology Applied
Scientific EffectPressure sensing: Pressure Increase

Data Source

PatentEP2647365B1Compression depth calculation system and compression depth calculation method
Publication Date: 2017.03.15 HITACHI LTD
  • EP2647365B1 patent drawingFigure 1
  • EP2647365B1 patent drawingFigure 2
  • EP2647365B1 patent drawingFigure 3(a)~3(c)

AI summary

It is an object to calculate a compression depth easily with high degree of accuracy. The present invention provides a compression depth calculation system 1000 configured to calculate the compression depth which is a magnitude of depression of the compressed object generated by the compression and includes a measuring apparatus 1 to be mounted on the object, and a compression depth calculating apparatus 2 configured to calculate the compression depth on the basis of information from the measuring apparatus 1. The compression depth calculation apparatus 2 calculates a coefficient of transformation on the basis of a second-order differential waveform created for the information acquired from a magnetic sensor 19 and acceleration information acquired from an acceleration sensor 13, creates a displacement waveform of a compressed portion by multiplying the acquired information by the coefficient of transformation, and calculates the compression depth on the basis of the displacement waveform.