Ventilator Lung-Model Control for Restrictive Lung Protection
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Solution Overview
Problem
Existing ventilation modes, such as the adaptive support ventilation (ASV) mode, are not suitable for patients with restrictive lung diseases like ARDS or fibrosis, leading to increased stress and potential complications due to mismatched pressure curves, resulting in diaphragmatic fatigue and respiratory acidosis.
Innovation Solution
A ventilator apparatus with a computing system that optimizes respiration frequency and parameters based on a lung model, using a closed-loop controller to minimize tidal volume and respiratory pressure, and includes a gas source to deliver controlled respiratory parameters, ensuring a protective ventilation mode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If adaptive support ventilation (ASV) mode is used based on Otis et. al equation, then spontaneous breathing is supported, but lung stress increases and diaphragmatic fatigue occurs due to mismatched pressure curves
Solution Approach 1:
The patent changes the fundamental parameters of ventilation by switching from pressure-controlled to volume-controlled delivery mode. This parameter change transforms the pressure curve morphology from rectangular to sinusoidal, matching natural breathing patterns and reducing lung stress while maintaining spontaneous breathing support.
Solution Approach 2:
The patent inverts the conventional approach by having the ventilator adapt to the patient's spontaneous breathing rhythm rather than imposing a fixed pressure pattern. The ventilator detects and follows the patient's intrinsic respiratory frequency, reversing the traditional control paradigm to reduce diaphragmatic fatigue.
2Ease of operation
If pressure controlled ventilation (PCV) is used to maintain set pressure, then patient comfort is improved, but tidal volume and respiratory pressure become excessive for restrictive lung diseases
Solution Approach 1:
The patent implements feedback control by continuously monitoring the patient's spontaneous respiratory frequency and using this information to adjust ventilator parameters. The ventilator detects the patient's intrinsic breathing rhythm and adapts its delivery pattern accordingly, ensuring appropriate tidal volumes for restrictive lung diseases while maintaining comfort.
Solution Approach 2:
The patent introduces dynamic adaptation where the ventilator parameters are not fixed but continuously adjusted based on real-time detection of the patient's respiratory frequency. This dynamic behavior allows the system to optimize tidal volume delivery for restrictive lung diseases while preserving patient comfort through spontaneous breathing support.
3Quantity of substance
If mandatory ventilation with rectangular pressure course is applied, then sufficient oxygenation is achieved, but respiratory work increases leading to respiratory acidosis
Solution Approach 1:
The patent employs periodic sinusoidal pressure variations that naturally align with the patient's spontaneous breathing rhythm. This periodic action replaces the harsh rectangular pressure course with smooth oscillations that reduce the work of breathing while maintaining sufficient oxygenation through synchronized breath delivery.
Data Source
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AI summary
The invention comprises a ventilation apparatus and method for operating a ventilator of a ventilator apparatus, by using a computing system, wherein in the method a duration ratio factor (D1, D2) is set in the computing system; a minute volume (Mv) is determined; a functional dead space volume (Vd) is determined; a time constant (R*C) is determined; a respiration frequency (f) is computed, based on a previously defined lung model (LM), depending on said determined minute volume (Mv), said determined functional dead space (Vd), said determined time constant (R*C) and said set duration ratio factor (D1,D2), where said computed respiration frequency (f) is optimized on at least one minimum of a delivered parameter (G_tot); an inspiratory time (Ti) and an expiratory time (Te) are determined; a tidal volume (Vt) and said determined minute volume (Mv) is computed; and a delivered respiratory parameter is closed loop controlled.