Non-Invasive Hemodynamic Estimation From Ventilation Signals
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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 pulmonary blood pressure and cardiac output.
Innovation Solution
A method that utilizes respiratory pressure and flow measurements from a conventional breathing apparatus to determine the arrival time of a blood pressure pulse at the lungs, enabling non-invasive estimation of pulmonary cardiac output and blood pressure without additional equipment, by analyzing cardiogenic oscillations caused by the blood pressure pulse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If invasive methods or additional equipment are used to determine hemodynamic parameters, then measurement precision is improved, but device complexity and ease of operation deteriorate
Solution Approach 1:
The ventilation system's existing sensors (respiratory pressure and flow sensors) are utilized for multiple purposes: their primary function for ventilation monitoring is maintained, and additionally they serve to detect cardiogenic oscillations for determining hemodynamic parameters such as pulmonary blood pressure and cardiac output. This eliminates the need for separate dedicated equipment.
Solution Approach 2:
The system uses its own existing resources (ventilation sensors and control unit) to perform the hemodynamic monitoring function without requiring external equipment. The control unit processes both ventilation parameters and hemodynamic data, making the system self-sufficient.
2Productivity
If continuous monitoring is implemented, then productivity is improved, but device complexity worsens
Solution Approach 1:
The system continuously monitors hemodynamic parameters by constantly analyzing cardiogenic oscillations in the respiratory pressure and flow signals. The control unit processes these signals in real-time during mechanical ventilation, enabling continuous rather than intermittent monitoring of pulmonary blood pressure and cardiac output.
Solution Approach 2:
The same ventilation sensors and control unit that manage mechanical ventilation continuously also perform continuous hemodynamic monitoring, eliminating the need for separate continuous monitoring equipment.
3Measurement precision
If ECG sensors or peripheral equipment are used, then measurement precision is improved, but ease of operation worsens
Solution Approach 1:
The system uses its own existing sensors (respiratory pressure and flow sensors) to detect heartbeat information through cardiogenic oscillations, eliminating the need for separate ECG sensors or peripheral equipment. The control unit processes these self-generated signals to determine hemodynamic parameters.
Solution Approach 2:
Cardiogenic oscillations serve as an intermediary phenomenon that links respiratory measurements to cardiac function. The oscillations in respiratory pressure and flow caused by heartbeats allow the system to infer cardiac parameters without direct cardiac sensing.
4Measurement precision
If pulmonary PTT measurement is implemented, then measurement precision is improved, but device complexity worsens
Solution Approach 1:
Cardiogenic oscillations in respiratory pressure and flow serve as intermediaries that allow indirect measurement of pulmonary pulse transit time. The oscillations provide timing information about cardiac events without requiring direct pulmonary artery pressure measurement or specialized equipment.
Solution Approach 2:
The ventilation system's own sensors and control unit perform the pulmonary PTT measurement function, eliminating the need for separate measurement equipment or complex setup procedures.
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, precise, and equipment-free monitoring of hemodynamic parameters like pulmonary cardiac output and blood pressure, using existing ventilation system sensors, without the need for additional hardware or modifications to the ventilation process.
Implementation Method 1
analyzing cardiogenic oscillations caused by the blood pressure pulse
Data Source
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) at which a blood pressure pulse caused by the heartbeat reaches the lungs of the subject. The method comprises the steps of measuring (S31) a respiratory pressure and/or a respiratory flow, and determining (S33) the arrival point in time (tarr_pulm) from a change in the measured respiratory pressure and/or the respiratory flow resulting from a change in lung volume caused by the arrival of the blood pressure pulse to the lungs of the subject.