Defibrillator Shock Index Using Wavelet Transform

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

During cardiac arrest, the chest compressions administered during CPR create artifacts in ECG readings, making it difficult for rescuers to accurately diagnose shockable arrhythmias like VF or pulseless V-tach, leading to indeterminate decisions that can result in insufficient oxygen supply to vital organs.

Innovation Solution

A medical device adjusts thresholds and generates a shock index based on analysis factors such as previous heart rhythms, age, chest compression method, and physiological parameters to improve the accuracy of identifying shockable rhythms, and outputs recommendations for defibrillation shocks, while also removing chest compression artifacts from ECG signals using filters like Wiener or Kalman filters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If chest compressions are administered during CPR, then blood flow to vital organs is maintained, but artifacts are created in ECG readings making diagnosis difficult

Engineering Contradiction:

Improveblood flow to vital organsVSAvoidECG reading accuracy

Core Design Contradiction:

ProductivityVSMeasurement precision

Solution Approach 1:

The ECG signal analysis is segmented into multiple frequency components using wavelet transform. This allows the system to separate the compression artifacts (which occupy specific frequency ranges) from the underlying cardiac rhythm, enabling accurate diagnosis despite ongoing chest compressions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Wavelet transform acts as an intermediary mathematical tool that mediates between the compressed ECG signal and the diagnostic requirements. It transforms the signal into a time-frequency representation that reveals hidden cardiac patterns while filtering out compression-related distortions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Device complexity

If traditional ECG analysis is used during CPR, then the system remains simple, but the ability to accurately identify shockable rhythms is reduced

Engineering Contradiction:

Improveanalysis system simplicityVSAvoidshockable rhythm identification accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent replaces traditional mechanical/time-domain ECG analysis with a mathematical transformation approach (wavelet transform). This substitution enables frequency-based analysis that can distinguish cardiac rhythms from compression artifacts, significantly improving diagnostic accuracy without requiring hardware changes

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The analysis method changes from examining ECG signals in the time domain to analyzing them in the frequency domain through wavelet transformation. This parameter change in the analysis approach allows the system to identify shockable rhythms by their frequency characteristics even during chest compressions

Inventive Principle:

Principle #35Parameter changes

3Speed

If defibrillation shock is administered without accurate diagnosis, then treatment can be delivered quickly, but dangerous shocks may be given to patients without VF or pulseless V-tach

Engineering Contradiction:

Improvedefibrillation delivery speedVSAvoiddefibrillation safety

Core Design Contradiction:

SpeedVSReliability

Solution Approach 1:

The system performs preliminary frequency-domain analysis of the ECG signal before making defibrillation decisions. By applying wavelet transform and analyzing frequency characteristics in advance, the system can confidently identify shockable rhythms and issue rapid defibrillation commands without compromising safety

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system uses feedback from the wavelet-transformed ECG analysis to continuously monitor rhythm changes and update defibrillation recommendations. This feedback mechanism ensures that shocks are only recommended when the frequency analysis confirms a shockable rhythm, maintaining high reliability while enabling rapid response

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

The solution enhances the device's ability to accurately determine the presence of shockable rhythms, reducing the likelihood of indeterminate decisions and ensuring timely defibrillation, thus improving patient outcomes by maintaining adequate oxygen supply to vital organs.

Implementation Method 1

removing chest compression artifacts from ECG signals using filters like Wiener or Kalman filters

Methodology Applied

Scientific EffectSignal filtering: Filter (electronic)

Data Source

PatentUS20220193430A1Enhanced defibrillation shock decisions

Publication Date: 2022.06.23 STRYKER CORP

AI summary

Defibrillators providing enhanced recommendations of whether to administer a defibrillation shock to patients are described. An example defibrillator determines an analysis factor, such as whether a patient has previously exhibited high-amplitude or “coarse” ventricular fibrillation (VF) during a particular time period. The defibrillator generates a shock index based on an electrocardiogram (ECG) of the patient and determines whether the patient is exhibiting a shockable rhythm by comparing the shock index to a threshold. The defibrillator generates the shock index and/or the threshold based on the analysis factor. The defibrillator outputs a recommendation based on the determination of whether the patient is exhibiting the shockable rhythm.