Tissue Perfusion Sensor Using Multi-Wavelength Segmentation

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Solution Overview

Problem

Implantable medical devices (IMDs) face challenges in accurately monitoring tissue perfusion, which is crucial for detecting cardiac arrhythmias and other hemodynamic insufficiencies, as existing optical sensors struggle to reliably detect changes in tissue perfusion due to arrhythmias, leading to delayed or inappropriate therapy delivery.

Innovation Solution

The implementation of a tissue perfusion sensor (TPS) within an implantable cardioverter defibrillator (ICD) that uses a combination of light emitting and detecting portions to generate signals responsive to tissue perfusion changes, including an alternating current (AC) component indicative of blood flow pulsatility, allowing for real-time monitoring and therapy adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing optical sensors are used to monitor tissue perfusion, then the device can detect changes in light modulation, but the detection reliability is insufficient due to arrhythmias

Engineering Contradiction:

Improvedetection reliabilityVSAvoidtissue perfusion detection accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

The patent segments the optical sensor system into multiple independent light detecting portions, each detecting light at different wavelengths. By dividing the detection function across multiple segments, the system can independently analyze signals from each portion and combine results to improve overall detection reliability and accuracy, overcoming the limitations of single-sensor approaches in arrhythmic conditions

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent changes the parameter of light wavelength by using multiple light detecting portions that detect different wavelengths. This allows the system to capture multiple parameters of tissue interaction with light, enabling more robust perfusion measurement that is less susceptible to arrhythmia-induced variations in any single wavelength signal

Inventive Principle:

Principle #35Parameter changes

2Loss of information

If optical sensors monitor tissue perfusion changes, then diagnostic information is provided, but therapy delivery is delayed or inappropriate due to unreliable detection

Engineering Contradiction:

Improvediagnostic information qualityVSAvoidtherapy delivery timing

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The patent implements feedback by continuously monitoring tissue perfusion using multiple light detecting portions and using this information to及时调整 therapy delivery. The system processes signals from multiple wavelengths in real-time, providing continuous feedback on tissue perfusion status, which enables timely and appropriate therapy delivery rather than delayed or inappropriate responses

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent performs preliminary action by using multiple light detecting portions to pre-assess tissue perfusion status before making therapy delivery decisions. The system continuously gathers diagnostic information from multiple wavelengths, allowing it to anticipate perfusion changes and prepare for timely therapy intervention before critical conditions develop

Inventive Principle:

Principle #10Preliminary action

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 solution enables precise detection of tissue perfusion changes, facilitating timely and appropriate therapy delivery, such as defibrillation shocks, thereby improving patient outcomes by accurately assessing cardiac function and arrhythmia management.

Implementation Method 1

optical sensors configured to detect changes in light modulation by a body fluid or tissue measurement volume

Methodology Applied

Scientific EffectLight absorption and scattering by tissue: Absorption (EM radiation)

Implementation Method 2

light detecting portion...generate a signal responsive to tissue perfusion changes

Methodology Applied

Scientific EffectPhotodetection: Photoelectric Effect

Implementation Method 3

detect changes in light modulation by a body fluid or tissue measurement volume due to a change in a physiological condition

Methodology Applied

Scientific EffectPulsatile flow modulation of light transmission:

Data Source

PatentUS8260415B2Optical sensor and method for detecting a patient condition

Publication Date: 2012.09.04 MEDTRONIC INC

AI summary

An implantable medical device for monitoring tissue perfusion that includes a light source emitting a light signal and a light detector receiving emitted light scattered by a volume of body tissue. The light detector emits a signal having an alternating current component corresponding to the pulsatility of blood flow in the body tissue volume. A processor receives the current signal and determines a patient condition in response to the alternating component of the current signal.