Medical Ventilator with Lung Model

This example models a positive-pressure medical ventilator system. A preset flow rate is supplied to the patient. The lungs are modeled with the Translational Mechanical Converter (MA), which converts moist air pressure into translational motion. By setting the Interface cross-sectional area to unity, displacement in the mechanical translational network becomes a proxy for volume, force becomes a proxy for pressure, spring constant becomes a proxy for respiratory elastance, and damping coefficient becomes a proxy for respiratory resistance.

The exchange of oxygen and carbon dioxide in the moist air mixture is not currently modeled.

Model

Check Valve 1 Subsystem

Control Signal Subsystem

Humidifier Subsystem

Simulation Results from Scopes

Simulation Results from Simscape Logging

This plot shows the temperature and relative humidity of air flowing through the inspiratory and expiratory tubes. Room air is heated and humidified before it is supplied to the patient.

This plot shows the accumulation of condensed water in the expiratory tube, which should be drained periodically. The water comes from the humidifier and the patient's respiration.