Mechanical Ventilator Pressure Control for Target Tidal Volume
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Solution Overview
Problem
Existing mechanical ventilation systems face challenges in synchronizing with patient respiratory effort, particularly in volume-controlled modes, leading to discomfort or inadequate tidal volume delivery, and pressure-controlled modes fail to maintain consistent volume, causing asynchrony and increased workload.
Innovation Solution
A ventilator system that adjusts pressure based on tidal volume deviations to achieve target volume, using a method that classifies cycles, computes pressure steps, and regulates pressure to ensure consistent tidal volume delivery, accommodating respiratory variability through adaptive sample size adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If pressure controlled cycles are used to maintain constant pressure in the patient's airway, then pressure stability is improved, but volume control deteriorates due to variable flow demand
Solution Approach 1:
The system continuously measures the actual volume delivered to the patient and uses this feedback to dynamically adjust the pressure control parameters. A microprocessor monitors volume measurements from respiratory cycles and modifies pressure delivery to achieve the target volume, resolving the contradiction between pressure stability and volume precision through closed-loop control
Solution Approach 2:
The system dynamically changes pressure parameters based on measured volume deviations. By adjusting pressure magnitude and duration in response to actual volume measurements, the system maintains both pressure control and achieves precise volume delivery, transforming fixed pressure control into adaptive pressure-volume control
2Manufacturing precision
If volume controlled cycles with fixed flow pattern are used to ensure precise volume delivery, then volume control precision is improved, but pressure variability worsens due to changes in respiratory mechanics
Solution Approach 1:
The system transitions from static fixed-flow volume control to dynamic pressure-adjusted volume control. By continuously adapting pressure parameters based on real-time volume measurements and patient response, the system maintains volume precision while allowing pressure to vary naturally with respiratory mechanics, eliminating the need for fixed flow patterns
3Speed
If the ventilator responds quickly to patient breathing variability, then synchronization with patient effort is improved, but volume control precision deteriorates due to insufficient sampling
Solution Approach 1:
The system performs preliminary volume measurements over multiple respiratory cycles before making pressure adjustments. By accumulating volume data across several cycles and analyzing patterns, the system builds a reliable baseline that enables rapid future responses while maintaining measurement precision through adequate sampling
Solution Approach 2:
The system uses a window of multiple respiratory cycles (excessive sampling beyond single-cycle minimum) to establish volume patterns and patient variability characteristics. This oversampling approach ensures measurement precision while enabling faster adaptive responses by pre-characterizing patient breathing patterns
4Device complexity
If a fixed number of respiratory cycles are used for volume assessment, then system simplicity is maintained, but adaptability to patient variability worsens
Solution Approach 1:
The system dynamically adjusts the number of respiratory cycles used for volume assessment based on detected patient variability. When high variability is detected, the system increases the sampling window to ensure accurate characterization, while during stable periods it uses fewer cycles, adapting the complexity of volume assessment to match patient needs
Data Source
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AI summary
A method for controlling mechanical lung ventilation is described. The method may include supplying a breathing gas to an airway of a patient in an intermittent way such that a plurality of respiratory cycles are formed; measuring a volume received by the patient in one or more respiratory cycles of the plurality of respiratory cycles; comparing the measured volume of each of the one or more respiratory cycles with a user defined target volume; attributing a classifying score to each of the one or more respiratory cycles based at least partially on a deviation between the measured volume and the user defined target volume; summing the classifying scores and dividing the result by a sample size of the one or more respiratory cycles; attributing a pressure step value based at least partially on the division result; and adding the pressure step value to a present pressure.