Adaptive Base Flow Scheduling for Ventilator Leak Compensation
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Solution Overview
Problem
Medical ventilators face challenges in maintaining patient-machine synchrony and accurate spirometry data due to system leaks, which can lead to discomfort and inaccurate tidal volume measurements, especially in neonatal conditions where flow rates are smaller and more critical.
Innovation Solution
The implementation of adaptive base flow scheduling and inspiratory trigger threshold adjustments based on estimated leak flow changes, using sensors to monitor and adjust the ventilator settings during exhalation to compensate for leaks and prevent false triggering, thereby optimizing patient-ventilator synchrony and spirometry accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If system leaks are present in the ventilator tubing, then patient comfort and synchrony deteriorate, but increasing base flow to compensate for leaks increases the uncertainty in tidal volume measurements
Solution Approach 1:
The patent implements dynamic adjustment of base flow rate during the exhalation phase. The system transitions from a static base flow approach to a dynamic one where the base flow rate is progressively reduced over time during exhalation, allowing the system to adapt to leak conditions while minimizing interference with tidal volume measurements.
Solution Approach 2:
The system performs preliminary leak compensation by delivering an elevated base flow at the beginning of exhalation to account for anticipated leaks, then progressively reduces the base flow rate as exhalation progresses. This preliminary action ensures synchrony is maintained during the critical early exhalation period while minimizing measurement interference later.
2Reliability
If base flow is increased to compensate for system leaks, then patient-machine synchrony improves, but false inspiratory triggers may occur
Solution Approach 1:
The system dynamically adjusts the base flow rate during exhalation, starting with a higher rate to prevent false triggers during early exhalation when leaks are most problematic, then progressively reducing the rate as exhalation progresses, thereby maintaining synchrony while minimizing the risk of false inspiratory triggers.
Solution Approach 2:
The patent applies periodic modulation of base flow during the exhalation phase, where the flow rate varies systematically over time rather than remaining constant. This periodic variation allows the system to provide enhanced compensation during critical periods while reducing compensation during periods when false triggering risk is lower.
3Measurement precision
If adaptive base flow scheduling is implemented to compensate for leaks, then spirometry accuracy improves, but device complexity increases
Solution Approach 1:
The system changes the base flow parameter dynamically during exhalation based on the detected leak rate. By adjusting this single critical parameter (base flow rate) as a function of time and leak magnitude, the system achieves improved spirometry accuracy without requiring fundamental redesign of the entire control architecture.
Solution Approach 2:
The patent implements feedback control where the measured leak flow rate is used to adjust the base flow scheduling in real-time. The system continuously monitors the exhalation flow, calculates the leak component, and uses this feedback to adaptively modify the base flow rate, creating a closed-loop control system that improves accuracy without excessive complexity.
Data Source
AI summary
This disclosure describes systems and methods for providing adaptive base flow scheduling during ventilation of a patient to optimize patient-machine synchrony and accuracy of estimated exhaled as well as inhaled tidal volumes. Further, this disclosure describes systems and methods for providing adaptive inspiratory trigger threshold scheduling during the adaptive base flow scheduling. Further still, this disclosure describes systems and methods for determining an estimated leak flow and adjusting the adaptive base flow scheduling and the adaptive inspiratory trigger threshold scheduling based on the estimated leak flow. Moreover, this disclosure describes systems and methods for determining a change in the estimated leak flow and adjusting the adaptive base flow scheduling and the adaptive inspiratory trigger threshold scheduling based on the change in the estimated leak flow.