Ventilation and CO2 Exchanger Control Using Expiratory CO2 Trends
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Solution Overview
Problem
Current methods for controlling and regulating CO2 and O2 exchange in non-invasive lung ventilation and extracorporeal blood gas exchange are often based on subjective experience, lacking reproducibility and objective, continuous measurements, which complicates evidence-based treatment guidelines and increases the risk of complications, especially in patients with chronic obstructive lung disease.
Innovation Solution
A system that uses a trend parameter, calculated as a dimensionless quotient of current and initial expiratory CO2 concentrations, to objectively control and regulate CO2 exchange, ensuring a stable and acceptable CO2 partial pressure in the blood by maintaining a constant expiratory CO2 concentration, independent of influencing factors, using a control system with a controller and CO2 exchanger.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If subjective experience-based control methods are used for CO2 and O2 exchange, then operational flexibility is maintained, but reproducibility and measurement precision deteriorate
Solution Approach 1:
The patent implements a feedback control system that continuously measures expiratory CO2 concentration and uses this information to automatically adjust ventilation parameters. The measured expiratory CO2 concentration serves as feedback to the control system, which then modifies ventilation settings to maintain target CO2 levels, replacing subjective judgment with objective measurement-driven control.
Solution Approach 2:
The patent replaces the mechanical/manual control method (subjective experience-based adjustment) with an automated control system that uses sensors and algorithms. The control system automatically calculates ventilation parameters based on measured expiratory CO2 concentration, substituting human judgment with an automated decision-making system that provides reproducible and objective control.
2Productivity
If invasive ventilation is used to ensure CO2 removal, then CO2 exchange effectiveness is improved, but patient risk and complication probability increase
Solution Approach 1:
The patent enables the respiratory system to maintain adequate CO2 removal through optimized non-invasive ventilation parameters, determined objectively by expiratory CO2 measurements. The system automatically adjusts ventilation to meet the patient's metabolic demands without requiring invasive procedures, allowing the patient's own respiratory system to function with minimal external intervention.
Solution Approach 2:
The patent dynamically adjusts ventilation parameters (tidal volume, respiratory rate, inspiratory pressure) based on real-time expiratory CO2 concentration measurements. By continuously monitoring and adjusting these parameters, the system maintains effective CO2 removal while operating within the safer non-invasive ventilation modality, avoiding the need to switch to invasive ventilation.
3Reliability
If non-invasive mask ventilation is used, then patient safety is improved, but measurement accuracy and control reliability deteriorate due to mask leaks and varying conditions
Solution Approach 1:
The patent measures expiratory CO2 concentration directly from the patient's breath during non-invasive ventilation, using the actual breath being delivered through the mask as the measurement source. This approach leverages the existing ventilation flow rather than being disrupted by it, and the measurements are used to objectively verify and adjust ventilation effectiveness despite the presence of mask leaks or varying patient conditions.
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
Provides an objectively comparable and reproducible control method for CO2 partial pressure in the blood, optimizing CO2 exchange and reducing the risk of complications by maintaining a medically acceptable CO2 concentration, even in cases of mask leaks or varying patient conditions.
Implementation Method 1
extracorporeal membrane oxygenation (ECMO; also known as Extracorporeal Life Support = ECLS) is known from so-called heart-lung machines (HLM)
Implementation Method 2
supporting the patient's lungs through various forms of mechanical-pneumatic respiratory support (ventilators)
Data Source
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AI summary
The invention relates to a system (10) for supporting the blood gas exchange of a patient (12) by means of a respiratory device (14) and by means of a CO2 exchanger (16). The invention further relates to a method for operating such a system (10), wherein by means of a sensor system (20), a measured value relating to an expiratory, or end-expiratory CO2 concentration in the respiratory gas of the patient (12) can be detected. By means of an operating action, a measured value can be selected as a starting value. Using the starting value and in each case, a currently determined measured value, a trend parameter can be determined, wherein a difference from a target value for the trend parameter and in each case, a current value of the trend parameter can be fed to a controller (42), which acts on the CO2 exchanger (16).