Ventilator Control for Detecting Lung Opening and Closing Pressure
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Solution Overview
Problem
Existing ventilation methods struggle to accurately identify the opening and closing pressures of the respiratory system in patients, leading to potential lung collapse and incorrect assessment of ventilation situations, which can cause local injuries and affect prognosis.
Innovation Solution
A control unit for ventilators that performs ventilation maneuvers to open and close sections of the respiratory system, using sensor data to determine opening and closing pressures from pressure-dependent curves in capnograms or oxigrams, allowing for precise identification without complex calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional PEEP titration methods are used to determine opening and closing pressures, then ventilation parameters can be adjusted, but the process is time-consuming and requires multiple breaths
Solution Approach 1:
The patent performs a lung recruitment maneuver before the actual ventilation to pre-open collapsed lung sections. This preliminary action allows the subsequent ventilation to proceed with already-recruited lung tissue, eliminating the need for time-consuming iterative PEEP titration while maintaining accurate pressure determination
Solution Approach 2:
Instead of performing multiple sequential PEEP titration steps, the patent uses a single recruitment maneuver followed by direct measurement of opening and closing pressures from the pressure-volume curve. This skips the iterative process and rushes through to the final measurement, significantly reducing time while maintaining precision
2Measurement precision
If pressure measurements are taken during ventilation maneuvers, then opening and closing pressures can be determined, but the pressure in airways may differ significantly from pressure in alveoli leading to incorrect assessment
Solution Approach 1:
The patent uses the pressure-volume curve obtained during the recruitment maneuver as an intermediary to indirectly determine alveolar pressure characteristics. By analyzing the relationship between applied pressure and lung volume changes, the system infers alveolar pressure conditions without requiring direct alveolar measurement, thus bridging the information gap between airway and alveolar pressures
3Reliability
If ventilation pressure is elevated over a relatively long period to ensure lung opening, then opening pressure can be achieved, but the risk of lung overexpansion increases
Solution Approach 1:
The patent continuously monitors the pressure-volume relationship during the recruitment maneuver and uses this feedback to determine the exact opening pressure point. By detecting the inflection point where lung sections begin to open, the system adjusts pressure dynamically, ensuring sufficient lung opening while immediately stopping before overexpansion occurs
Solution Approach 2:
The ventilation system dynamically adjusts pressure during the recruitment maneuver based on real-time lung response. Pressure is increased only as much as needed to open collapsed sections, with continuous adaptation to the actual lung mechanics, rather than applying a fixed elevated pressure that could cause overexpansion
Data Source
AI summary
A ventilator comprises a respiratory air connector connected to the respiratory system of a patient; an actuation system for providing a respiratory air flow; a sensor system for creating measurement data relating to the ventilation. A control unit for the ventilator is configured to carry out: creating a control signal for controlling the actuation system such that a ventilation maneuver is performed, within which at least one section of the respiratory system is opened/closed in an inhalation/exhalation phase; receiving the measurement data indicating a pressure-dependent curve of an amount of a respiratory gas inhaled/exhaled by the patient as a function of a pressure of the respiratory air; determining an opening/closing pressure corresponding to a pressure of the respiratory air at which at least one section of the respiratory system is opened/closed, by evaluating a section of the pressure-dependent curve that relates to the inhalation/exhalation phase.