ECG T Wave Amplitude Monitoring for Noninvasive Blood Loss Detection

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Solution Overview

Problem

Current methods for detecting small decreases in blood volume postoperatively are invasive, time-consuming, and lack effective noninvasive indicators, making it difficult to detect early signs of blood loss in patients.

Innovation Solution

A noninvasive method using electrocardiogram (ECG) measurements, specifically T wave amplitudes and T/R amplitude ratios, to detect small changes in blood volume by standardizing electrode placement and correlating changes in ECG readings with blood volume loss, allowing for early detection of potential blood volume decreases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional methods (blood pressure and heart rate measurements) are used to monitor blood volume, then personnel can detect blood loss, but the measurements are time-consuming and require more personnel

Engineering Contradiction:

Improveblood loss detection capabilityVSAvoidmeasurement time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces manual mechanical measurements (blood pressure and heart rate taken by nurses every 15 minutes) with an automated electronic monitoring system that continuously measures ECG signals and calculates blood volume indicators, eliminating the need for frequent manual interventions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system provides continuous automated monitoring of ECG signals and blood volume indicators, replacing discontinuous manual measurements taken every 15 minutes, thereby enabling constant surveillance without additional personnel time

Inventive Principle:

Principle #20Continuity of useful action

2Reliability

If blood pressure and heart rate are monitored, then some blood loss can be detected, but these indicators remain normal when blood volume loss is not more than 10 percent

Engineering Contradiction:

Improveblood loss detection capabilityVSAvoidearly blood loss detection sensitivity

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the monitoring parameter from traditional blood pressure and heart rate to ECG-derived blood volume indicators (such as QRS amplitude, T wave amplitude, and ST segment changes), which are more sensitive to early blood volume losses of less than 10 percent

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The system uses ECG signals as an intermediary indicator that reflects blood volume changes before they manifest in traditional vital signs, allowing detection of early blood loss through electrical cardiac activity changes

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If ECG amplitude measurements are used to detect blood volume changes, then early blood loss can be detected, but chest lead amplitude measurements have great variations due to non-standardized electrode placement

Engineering Contradiction:

Improveearly blood loss detection sensitivityVSAvoidelectrode placement standardization

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent focuses measurements on specific localized ECG leads (particularly precordial leads V1-V6) that show consistent blood volume sensitivity, rather than using all ECG leads, thereby reducing variability from non-standardized placement in less critical areas

Inventive Principle:

Principle #3Local quality

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 early and accurate detection of small postoperative blood volume decreases, reducing the need for frequent blood pressure measurements and allowing nurses to allocate time more effectively, potentially reducing the number of personnel required in recovery rooms.

Implementation Method 1

a noninvasive method using electrocardiogram (ECG) measurements, specifically T wave amplitudes and T/R amplitude ratios, to detect small changes in blood volume

Methodology Applied

Scientific EffectElectrocardiogram: Conduction (electrical)

Data Source

PatentUS10292627B2Method and apparatus for noninvasive detection of potential symptomless blood loss

Publication Date: 2019.05.21 BIOPOTENTIAL OY LTD

AI summary

A method including obtaining a first electrocardiography [“ECG”] reading from a test subject when the test subject is believed to not suffer from blood volume loss and obtaining a second ECG reading from the test subject when the test subject is in an unknown condition regarding blood volume loss. The first ECG reading and the second ECG reading are obtained using the same electrode positions on the test subject and include sets of ECG signals which, based on experimental data, respond to small decrease in blood volume by a statistically significant strength decrease. If the second ECG reading exhibits a statistically significant strength decrease compared with the first ECG reading, an alert condition is raised, which indicates potential small decrease in blood volume. The method can be embodied as a stand-alone ECG apparatus or as an add-on unit to an ECG apparatus.