Oxygen Delivery Control for Stable FdO2 in Flow Therapy
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Solution Overview
Problem
Current methods for controlling oxygen delivery in respiratory therapy apparatuses face challenges in maintaining a consistent target fraction of oxygen delivered (FdO2) due to fluctuating total flow rates during a patient's breath, requiring constant manual adjustment and lacking efficient automatic control systems.
Innovation Solution
A respiratory apparatus with a controller that determines a target supplemental oxygen flow rate based on total flow rate, ambient air oxygen fraction, and supplemental gas oxygen fraction, using a valve model to adjust the valve current and update the model in real-time to maintain target FdO2 levels, incorporating sensors for flow rate and oxygen composition measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If manual adjustment methods are used to control oxygen delivery, then the system is simpler in structure, but the consistency of target FdO2 levels deteriorates due to fluctuating flow rates requiring constant adjustment
Solution Approach 1:
The patent implements a closed-loop feedback control system where the controller continuously monitors the actual FdO2 levels and total flow rate, then automatically adjusts the supplemental oxygen flow rate to maintain the target FdO2. This feedback mechanism eliminates the need for constant manual adjustment while ensuring consistent oxygen delivery despite flow rate fluctuations.
Solution Approach 2:
The control system performs self-adjustment by automatically calculating the required supplemental oxygen flow rate based on real-time sensor data and valve model parameters. The system serves itself by autonomously maintaining target FdO2 levels without requiring external manual intervention, thereby improving reliability while managing complexity through automation.
2Ease of operation
If automatic control systems are implemented to maintain target FdO2, then the consistency of oxygen delivery improves, but the device complexity increases
Solution Approach 1:
The patent replaces manual mechanical adjustment with an automated electronic control system that uses sensors, a controller, and electronic valve actuation. This substitution provides ease of operation through automatic control while managing complexity by integrating functions into a coordinated electronic system rather than requiring complex mechanical adjustment mechanisms.
Solution Approach 2:
The controller performs multiple functions including calculating target supplemental oxygen flow rate, determining valve current settings, updating valve model parameters, and coordinating with sensors. This multi-functionality consolidates control capabilities into a single device, improving ease of operation while containing overall system complexity through functional integration.
3Manufacturing precision
If valve model updates are performed in real-time, then the precision of oxygen flow control improves, but the processing requirements and system complexity increase
Solution Approach 1:
The patent updates valve model parameters such as minimum current and flow rate estimates based on real-time sensor data rather than continuously recalculating all control parameters. This partial updating approach maintains precision of oxygen flow control by keeping model parameters current while reducing processing requirements compared to complete real-time recalculation of all control variables.
Data Source
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Figure 1B
Figure 1C~1F
AI summary
The present disclosure provides for a control system for a flow therapy apparatus. The control system can control delivery of a fraction of delivered oxygen (FdO2) to a patient. The control system can maintain the FdO2 at a target level during a therapy session. The control system can automatically control an oxygen inlet valve in order to control the flow of oxygen to the patient.