Emergency NO Dosing Backup for Ventilator Flow Sensor Failure
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Solution Overview
Problem
Current NO delivery systems face challenges in maintaining accurate NO dosage during failures, such as signal loss from the flow sensor, leading to potential therapeutic interruptions and rebound effects in patients.
Innovation Solution
A gas supply installation with an emergency NO delivery system that includes an emergency solenoid valve, a flow control device, and piloting means to maintain a predetermined emergency flow rate of NO/N2 mixture, even in the event of signal loss from the flow sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow sensor and proportional solenoid valve are used to control NO delivery in real-time, then accurate NO dosage can be maintained, but the system becomes vulnerable to signal loss and malfunctions that interrupt therapy
Solution Approach 1:
The patent pre-calculates and stores the required NO flow rate based on previously measured patient flow rates before any malfunction occurs. This preliminary action ensures that when signal loss happens, the system immediately switches to emergency mode using the pre-determined flow rate, maintaining therapy continuity without interruption.
Solution Approach 2:
The patent implements an emergency backup system with a backup solenoid valve and emergency flow control device that are pre-configured to take over immediately upon detecting flow sensor signal loss. This cushioning mechanism protects against therapy interruption by having a ready-reserve system that activates automatically.
2Reliability
If manual emergency dosing is implemented after flow sensor failure, then therapy can be maintained, but there is a time delay that exposes the patient to rebound effects
Solution Approach 1:
The patent enables the system to automatically detect flow sensor failures and switch to emergency mode without requiring manual intervention. The control unit continuously monitors sensor signals and autonomously activates the backup system, eliminating the time delay associated with manual response and ensuring immediate therapy continuity.
Solution Approach 2:
The patent implements continuous monitoring of flow sensor signals with automatic feedback control. When signal loss is detected, the system immediately responds by switching to emergency dosing mode, creating a closed-loop control system that eliminates response delays and maintains continuous therapeutic coverage.
3Device complexity
If a fixed emergency flow rate is used after signal loss, then simple emergency dosing is achieved, but the dosage may not match the patient's actual needs
Solution Approach 1:
The patent pre-calculates the emergency NO flow rate based on the last valid patient flow rate measurement before signal loss occurs. This preliminary calculation ensures that the emergency dosing is personalized to the patient's actual needs rather than using a generic fixed rate, maintaining dosage accuracy while keeping the emergency system relatively simple.
4Measurement precision
If the proportional solenoid valve is controlled by flow sensor signals, then precise NO delivery is achieved, but the system fails when signals are lost
Solution Approach 1:
The patent divides the NO delivery system into two independent segments: a normal operation mode using the proportional solenoid valve controlled by flow sensor signals, and an emergency mode using a backup solenoid valve with pre-calculated flow rates. This segmentation allows each segment to be optimized for its specific function while providing fault tolerance through independence.
Solution Approach 2:
The patent pre-configures the emergency dosing parameters and backup valve settings before any failure occurs. This preliminary preparation enables the system to adapt immediately to signal loss by switching to the pre-configured emergency mode, maintaining both precision and adaptability without requiring complex real-time adjustments during failure.
Data Source
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AI summary
The invention relates to a gas supply system (1, 2) for a patient, comprising a NO delivery device (1), a NO injection line (111) with a valve device (113), a backup line (201) connecting to the injection line (111) and comprising a backup solenoid valve (202) and a flow control device (210), and control means (130); and a medical ventilator (2) that supplies breathing gas to a patient circuit (3) to which the NO delivery device (1) is connected. A flow sensor (100) provides the control means (130) with a signal measuring the gas flow rate in the patient circuit (3).In the event of an interruption in the reception of the measurement signal, the emergency solenoid valve (202) goes into the open position, the valve device (113) into the closed position and the flow control device (210) supplies the NO/N2 mixture at a preset emergency flow rate, determined from the measurement signal supplied by the flow sensor (100), before said interruption.