Lung Simulator Closed-Loop CO2 Control
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Solution Overview
Problem
Current lung simulators fail to realistically simulate the respiratory response to physiological CO2 partial pressure, which is crucial for testing respiratory equipment and training medical personnel, as they lack accurate representation of the complex respiratory regulation mechanisms and gas exchange processes.
Innovation Solution
The development of a closed-loop control system in a lung simulator that adjusts respiration frequency and tidal volume based on measured or calculated CO2 partial pressure, synchronizing CO2 delivery with the breathing pattern to mimic actual patient responses, using a CO2 measuring and delivery system that includes a valve design for precise CO2 flow and a controller to actuate the valve for pulse-width modulation, allowing for realistic simulation of EtCO2 curves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closed-loop control system with CO2 delivery is implemented, then the simulation realism of respiratory response is improved, but the device complexity increases
Solution Approach 1:
The patent combines the CO2 delivery system with the existing lung simulator platform, integrating multiple functions (CO2 injection, breath synchronization, closed-loop control) into a unified system. This merging approach improves simulation realism while managing complexity through integrated design rather than separate additive components.
Solution Approach 2:
The implementation of a closed-loop control system with CO2 delivery creates a feedback mechanism where the simulator monitors its own output (EtCO2) and automatically adjusts CO2 delivery to maintain physiological accuracy. This feedback loop significantly enhances simulation realism by dynamically adapting to simulated patient responses.
2Measurement precision
If CO2 delivery system with valve and controller is added, then the measurement precision of EtCO2 is improved, but the manufacturing cost increases
Solution Approach 1:
The patent introduces a CO2 delivery system with precisely controlled valve actuation as an intermediary mechanism to regulate CO2 injection timing and quantity. This intermediary system enables accurate EtCO2 measurement by ensuring controlled, physiological CO2 delivery, while the valve design allows for cost-effective manufacturing through standardized components.
3Stability of the object's composition
If CO2 is delivered during inhalation phase, then the homogeneity of gas mixing is improved, but the device complexity increases
Solution Approach 1:
The system performs preliminary action by delivering CO2 during the inhalation phase before exhalation occurs. This timing ensures that CO2 is introduced into the breathing circuit when fresh gas is flowing, allowing for better mixing homogeneity. The breath synchronization is achieved through simple phase detection rather than complex real-time control.
Solution Approach 2:
The CO2 delivery is implemented as a periodic action synchronized with the respiratory cycle, specifically during the inhalation phase. This periodic delivery pattern maintains consistent gas mixing homogeneity with each breath while using simple on/off valve control rather than continuous modulation, managing device complexity.
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 a more realistic simulation of respiratory responses to CO2 partial pressure, providing accurate training and testing of respiratory equipment, reducing the need for additional monitoring systems and minimizing costs by eliminating the need for capnography systems in some applications, while maintaining the benefits of a realistic patient response.
Implementation Method 1
The reading is returned to the simulation control loop as a CO2 partial pressure... using a CO2 measuring and delivery system
Data Source
AI summary
A system and method of delivering CO2 in a respiration closed-loop control system to a respiratory simulator includes (a) providing a CO2 supply to a respiratory simulator having a piston/cylinder arrangement; (b) providing flow control hardware between the CO2 supply and the piston/cylinder arrangement; (c) generating a first control signal representative of a predefined amount of CO2; and (d) providing the predefined amount of CO2 into the piston/cylinder arrangement. Thereafter, either (i) an end-tidal carbon dioxide partial pressure (EtCO2) value is determined based on an amount of CO2 emptied from the piston/cylinder arrangement during an exhalation phase of the respiratory simulator or (ii) an EtCO2 value is calculated via an equation. A second control signal is generated that is representative of a tidal volume and a breathing frequency representative of a physiological response to the EtCO2 value to effect corresponding movement of the piston in a next inhalation and exhalation phase.