Hemodynamic Monitoring via Pulse Transit Time Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current methods for monitoring hemodynamic status in patients, particularly those with heart failure, are limited by invasive procedures and lack of continuous, non-invasive monitoring solutions that can effectively track changes in blood pressure and vessel compliance over time.

Innovation Solution

The system employs one or more implantable and non-implantable devices to measure signals from tissue near and further along a circulatory path from the heart, calculating pulse transit times to assess hemodynamic status through wireless communication with an external monitoring device, which generates surrogate hemodynamic values and alerts based on trends and comparisons to baseline values.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If invasive procedures are used to monitor hemodynamic status, then measurement precision is improved, but device complexity and patient discomfort increase

Engineering Contradiction:
Improvehemodynamic status measurementVSAvoidmonitoring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces invasive mechanical pressure sensors with non-invasive optical detection methods. Optical sensors detect blood volume changes in tissue as the pulse wave passes through, substituting mechanical measurement with optical measurement to achieve non-invasive hemodynamic monitoring with adequate precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent uses tissue as an intermediary medium. Optical sensors detect pulse waves indirectly by measuring light absorption changes in tissue rather than directly measuring blood pressure in vessels. This intermediary approach enables non-invasive measurement while maintaining useful measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If continuous monitoring is implemented, then reliability of hemodynamic assessment is improved, but use of energy and device complexity increase

Engineering Contradiction:
Improvehemodynamic status assessmentVSAvoidenergy consumption by monitoring devices
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements periodic monitoring at optimized intervals rather than truly continuous monitoring. The system captures pulse wave signals at regular intervals sufficient to track hemodynamic trends and changes, reducing energy consumption while maintaining reliability for detecting clinically significant changes in heart failure patients.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent leverages the patient's own physiological pulse waves as the monitoring signal source. The system requires no external energy input to generate the measurement signal, as it passively detects naturally occurring pulse wave propagation through tissue using low-power optical sensors.

Inventive Principle:
Principle #25Self-service

3Ease of operation

If non-invasive optical sensors are used, then ease of operation is improved, but measurement precision deteriorates

Engineering Contradiction:
Improvemonitoring procedure simplicityVSAvoidblood pressure measurement accuracy
Core Design Contradiction:
Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces direct mechanical pressure measurement with optical detection of blood volume changes. This substitution improves ease of operation by enabling non-invasive measurement through tissue, while the precision is maintained sufficient for detecting hemodynamic trends and changes in heart failure management.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent measures a different physical parameter (optical absorption related to blood volume) rather than direct pressure. By monitoring changes in optical properties as the pulse wave passes through tissue, the system achieves ease of non-invasive operation while capturing hemodynamic information through parameter transformation.

Inventive Principle:
Principle #35Parameter changes

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 approach provides continuous, less invasive monitoring of hemodynamic status, enabling early detection of changes in blood pressure and vessel compliance, aiding in the management of heart failure and other cardiovascular conditions.

Implementation Method 1

a pulse wave propagates through the blood vessel, causing the tissue to expand and compress

Methodology Applied
Scientific EffectPulse wave propagation:

Data Source

PatentEP3506818A1Systems and methods for monitoring hemodynamic status
Publication Date: 2019.07.10 MEDTRONIC INC

AI summary

System and method for monitoring one or more signals to be used to assess the hemodynamic status of a patient. The one or more signals may be used to determine a plurality of pulse transit times. The plurality of pulse transit times may be used to determine hemodynamic status values that may be indicative of a patient's aggregate hemodynamic status.