Ventilation Apparatus Correcting Proximal Respiratory Gas Flow Sensor Drift
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Solution Overview
Problem
Existing ventilation devices face challenges in maintaining accurate respiratory gas flow measurements due to moisture and body fluid exposure affecting proximal respiratory gas flow sensors, leading to drift errors and reduced measurement accuracy, and require complex calibration processes that can be invasive and unreliable.
Innovation Solution
Incorporating a distal respiratory gas flow sensor to detect inspiratory flows and using a second model to calculate corrected inspiratory detection values by comparing with theoretical values, allowing for continuous and accurate ventilation with minimal disruption to the patient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a proximal respiratory gas flow sensor is used to detect respiratory gas flow, then measurement accuracy is improved, but the sensor is affected by moisture and body fluids causing drift errors over time
Solution Approach 1:
A distal respiratory gas flow sensor is introduced as an intermediary measurement point located downstream in the respiratory gas line. This distal sensor detects respiratory gas flow at a position less susceptible to moisture and body fluid contamination. The detected distal flow values are then used to calculate corrected proximal flow values through a calibration model, thereby indirectly obtaining accurate proximal measurements without exposing the proximal sensor directly to harmful environmental factors.
Solution Approach 2:
The system implements a feedback mechanism where distal respiratory gas flow sensor measurements are continuously used to update and correct proximal flow detection values. A calibration model stores the relationship between distal and proximal flow values, and this model is periodically updated using newly acquired distal measurements. The corrected proximal values are then fed back into the ventilation control system, creating a closed-loop feedback that maintains measurement accuracy over extended periods.
2Measurement precision
If cleaning and zero calibration are performed on the proximal respiratory gas flow sensor, then drift errors are reduced, but detection values are lost during calibration and patient ventilation is disrupted
Solution Approach 1:
The system maintains continuous detection of respiratory gas flow by using the distal sensor to provide measurement data during the entire operation, including during calibration phases. While the proximal sensor undergoes cleaning or zero calibration and temporarily loses detection capability, the distal sensor continues to monitor flow, ensuring that ventilation control is not interrupted. This allows calibration activities to proceed without stopping the useful action of patient ventilation.
Solution Approach 2:
The distal respiratory gas flow sensor serves as an intermediary that bridges the detection gap created when the proximal sensor is calibrated. During calibration periods when the proximal sensor cannot provide detection values, the distal sensor's measurements are used to maintain continuous flow monitoring and ventilation control, preventing any interruption in the critical function of patient support.
3Measurement precision
If a distal respiratory gas flow sensor is added to calculate corrected proximal values, then measurement accuracy is maintained over time, but device complexity increases
Solution Approach 1:
The distal respiratory gas flow sensor is designed to serve multiple functions: it acts as a primary measurement sensor during normal operation, serves as a backup during proximal sensor calibration, provides data for updating calibration models, and can detect flow patterns for ventilation cycle triggering. This multi-functionality justifies the addition of the extra sensor by maximizing its utility across different operational scenarios.
Solution Approach 2:
The system dynamically changes operational parameters by switching between using proximal sensor data directly during stable periods and using distal sensor-based corrected values during calibration or when drift is detected. The calibration model parameters are continuously updated based on distal measurements, allowing the system to adapt its measurement approach based on sensor performance and operational conditions, thereby optimizing accuracy while managing complexity.
4Measurement precision
If calibration is performed using a separate calibration device, then proximal sensor accuracy is improved, but the calibration process becomes invasive and complex
Solution Approach 1:
The calibration function is merged with the normal operational sensors by using the distal respiratory gas flow sensor, which is already permanently installed and operational during patient ventilation, to perform calibration of the proximal sensor. This eliminates the need for a separate, dedicated calibration device. The calibration process utilizes the existing distal sensor's measurements combined with a calibration model, integrating calibration capabilities into the routine operational infrastructure rather than requiring separate specialized equipment.
Data Source
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AI summary
The present invention relates to a ventilation device (10) for at least supplementary artificial ventilation of a patient (12), the data processing device (19) of which is configured to determine, based on a detection value output by a distal respiratory gas flow sensor (48), which represents an inspiratory distal respiratory gas flow in a calibration operating situation, an inspiratory calibration approximation value which represents an inspiratory detection value expected from a proximal respiratory gas flow sensor (44) when detecting the proximal inspiratory respiratory gas flow in the calibration operating situation, wherein the data processing device (19) is further configured tousing the calibration approximation value and a real inspiratory measurement value output by the proximal respiratory gas flow sensor (44) in the calibration operating situation, the at least one inspiratory error parameter is quantified according to a second model, and wherein the data processing device (19) is further configured to apply the at least one quantified inspiratory error parameter to real inspiratory measurement values output by the proximal respiratory gas flow sensor (44) during the further operation of the ventilation device (10) in order to convert the actual inspiratory measurement values of the proximal respiratory gas flow sensor (44) into corrected inspiratory measurement values with less absolute error.