Ventilator NO Backup Dosing for Flow Sensor Signal Loss
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Solution Overview
Problem
Current NO delivery systems in medical ventilators face challenges in maintaining accurate NO dosing during malfunctions, such as loss of signal from flow rate sensors or electrical disconnections, leading to potential adverse effects due to abrupt changes in NO concentration or complete cessation of therapy.
Innovation Solution
A backup NO dosing system with a backup solenoid valve and flow rate control device that switches to a pre-regulated backup gas flow rate based on last measured flow rates before signal loss, ensuring continuous NO therapy by bypassing the main injection line and using a proportional calibrated orifice system to adjust flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a main NO delivery system with flow rate sensor is used to control NO dosage, then accurate NO dosing can be achieved, but the system becomes vulnerable to signal loss and malfunctions that can cause abrupt cessation of therapy
Solution Approach 1:
The backup line is pre-configured with a solenoid valve and flow rate control device that can immediately activate upon detection of main system failure. The backup flow rate is pre-determined based on the desired dosage and last measured flow rate, allowing instantaneous switch-over without interruption to NO therapy delivery to the patient.
Solution Approach 2:
The system incorporates a redundant backup delivery path that cushions against the harmful effect of main system failure. This backup line with its own flow control mechanism ensures that if the main system fails, the therapeutic effect is maintained without abrupt cessation, protecting the patient from adverse effects of sudden NO concentration changes.
2Reliability
If a backup NO dosing system is added to ensure continuous therapy during malfunctions, then patient safety is improved, but the device complexity increases
Solution Approach 1:
The NO delivery system is segmented into two independent pathways: a main delivery line with full sensor and control integration, and a backup line with simplified solenoid valve and flow rate control. This segmentation allows the backup system to provide redundancy without requiring duplication of the entire complex main system, reducing overall complexity while maintaining reliability.
Solution Approach 2:
The backup line acts as an intermediary system that bridges the gap between complete system failure and continuous therapy. Rather than making the main system more complex with redundant sensors and controls, a simpler intermediary backup path is introduced that can take over when the main path fails, achieving reliability improvement with minimal complexity increase.
3Extent of automation
If the backup line uses a solenoid valve and flow rate control device, then automatic switching to backup flow rate is enabled, but the manufacturing cost and device complexity increase
Solution Approach 1:
The control means pre-determines the backup flow rate based on the desired dosage and the last measured flow rate from the main system before failure occurs. This preliminary calculation and pre-positioning of the backup system allows automatic activation without complex real-time decision algorithms, simplifying manufacturing while maintaining high automation for the critical switching function.
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
The system maintains desired NO concentrations during malfunctions, reducing the risk of adverse effects and ensuring continuous therapy by automatically switching to a pre-set backup flow rate, improving patient safety and stability of treatment.
Implementation Method 1
a solenoid valve which is configured so that, in the event of a malfunction with loss of the signal from the flow rate sensor, the solenoid valve opens
Implementation Method 2
a proportional calibrated orifice system to adjust flow rates
Data Source
AI summary
An installation for supplying gas to a patient, comprises an NO delivery device, an NO injection line with a valve device, a backup line that connects to the injection line and comprises a backup solenoid valve and a flow rate control device, and control means; and a medical ventilator that supplies a respiratory gas to a patient circuit to which the NO delivery device is connected. A flow rate sensor supplies the control means with a measurement signal of the gas flow rate in the patient circuit. In the event of interruption of reception of the measurement signal, the backup solenoid valve switches to an open position, the valve device switches to a closed position and the flow rate control device supplies the NO/N2 mixture at a pre-regulated backup flow rate, determined on the basis of the measurement signal supplied by the flow rate sensor, before said interruption.