Ventilator Pulse Transit Timing for Non-Invasive Hemodynamic Monitoring

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Solution Overview

Problem

Existing methods for non-invasive estimation of hemodynamic parameters during mechanical ventilation are invasive, require additional equipment, and are not suitable for continuous monitoring, particularly for determining pulmonary cardiac output (PCO) and pulmonary blood pressure (PBP), as they rely on ECG sensors or complex setups like ultrasound or magnetic resonance imaging.

Innovation Solution

A method that utilizes respiratory pressure and flow measurements to determine the time of a heartbeat and the arrival of a blood pressure pulse at the lungs or systemic circulation, allowing for the calculation of hemodynamic parameters such as PCO, PBP, systemic cardiac output (SCO), and systemic blood pressure (SBP) without additional sensors, by analyzing changes in respiratory curves and using established relationships to calculate these parameters from pulse transit times.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If ultrasound-based techniques are used for non-invasive PBP determination, then measurement precision is improved, but device complexity increases and ease of operation deteriorates due to requiring additional equipment and qualified personnel

Engineering Contradiction:

ImprovePBP determination accuracyVSAvoidequipment requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The ventilation system uses its own existing pressure and flow sensors to determine hemodynamic parameters, making the system self-sufficient without requiring additional external equipment like ultrasound transducers or ECG sensors

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The existing pressure and flow sensors in the ventilation system are made multi-functional by using them not only for respiratory monitoring but also for determining hemodynamic parameters such as PBP, PCO, SBP, and SCO through pulse transit time analysis

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If ECG sensors are used for determining pulse transit time, then measurement precision is improved, but device complexity increases due to requiring additional peripheral equipment

Engineering Contradiction:

Improveheartbeat timing accuracyVSAvoidsensor requirements

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The ventilation system determines the heartbeat time point by analyzing changes in its own measured respiratory pressure and flow, eliminating the need for external ECG sensors while maintaining the capability to accurately identify heartbeat events

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The respiratory pressure and flow measurements serve as an intermediary medium to indirectly detect heartbeat events and blood pressure pulse arrival times, replacing the direct electrical measurement approach of ECG sensors

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If magnetic resonance imaging is used for hemodynamic parameter determination, then measurement precision is improved, but device complexity increases and ease of operation deteriorates due to complex setup requirements

Engineering Contradiction:

Improvehemodynamic parameter accuracyVSAvoidbedside monitoring capability

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

The invention uses simple, inexpensive pressure and flow sensors that are already part of the ventilation system rather than expensive, complex imaging equipment like MRI or ultrasound machines, making the solution practical for routine bedside monitoring

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The ventilation system performs hemodynamic monitoring using its own integrated sensors without requiring additional specialized equipment or complex imaging setups, enabling straightforward bedside operation

Inventive Principle:

Principle #25Self-service

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 continuous, non-invasive estimation of hemodynamic parameters using existing ventilation system sensors, eliminating the need for additional equipment and providing precise, robust monitoring of PCO, PBP, SCO, and SBP without the complexity of ECG or ultrasound-based techniques.

Implementation Method 1

an arrival point in time at which a blood pressure pulse caused by the heartbeat reaches a point of arrival in the circulatory system of the subject

Methodology Applied

Scientific EffectPulse wave propagation:

Data Source

PatentUS12594389B2Non-invasive estimation of hemodynamic parameters during mechanical ventilation

Publication Date: 2026.04.07 MAQUET CRITICAL CARE

AI summary

The present disclosure relates to a method for non-invasive determination of a hemodynamic parameter of a mechanically ventilated subject (3) based on a point in time (thb) of a heartbeat of the subject and an arrival point in time (tarr_pulm, tarr_sys) at which a blood pressure pulse caused by the heartbeat reaches a point of arrival in the circulatory system of the subject. The method comprises the steps of measuring (S41) a respiratory pressure and/or a respiratory flow, and determining (S43) the point in time (thb) of the heartbeat from a change in the measured respiratory pressure and/or the respiratory flow resulting from a physical impact of the heart on the lungs of the subject (3) during the heartbeat.