Two different ways of expressing breathing, one as if using a ventilator at the mouth and the other one as human pleural muscle generating pressure gradient against external pressure. Three models used to compare differences.
These models compare three situations, each with two compartments having resistances, compliances, switches and initial masses of specie in the two tanks. The first model has a pressure source in external air as in the case of breathing support of patient with a ventilator. The second model has a pressure source attached to the most inner tank as in the case of regular human breathing, when the tension of pleural muscle controls the generated pressure difference. Depending on the compliances and volumes of the tanks, time elapsed to reach the stationary conditions may vary slightly. However, the two cases show the same long time flow and concentration characteristics. The last model shows the case when internal and external pressure sources are applied simultaneously. It simulates the situation when a patient initially on a breathing support starts to breath on his own, but the ventilator is still active.
The governing equations are
External Pressure Source at the mouth
**Pleural Muscle as a Pressure Source**
The equations for this model may be viewed by running the JSim model applet and clicking on the Source tab at the bottom left of JSim's Run Time graphical user interface. The equations are written in JSim's Mathematical Modeling Language (MML). See the Introduction to MML and the MML Reference Manual. Additional documentation for MML can be found by using the search option at the Physiome home page.
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Model development and archiving support at https://www.imagwiki.nibib.nih.gov/physiome provided by the following grants: NIH U01HL122199 Analyzing the Cardiac Power Grid, 09/15/2015 - 05/31/2020, NIH/NIBIB BE08407 Software Integration, JSim and SBW 6/1/09-5/31/13; NIH/NHLBI T15 HL88516-01 Modeling for Heart, Lung and Blood: From Cell to Organ, 4/1/07-3/31/11; NSF BES-0506477 Adaptive Multi-Scale Model Simulation, 8/15/05-7/31/08; NIH/NHLBI R01 HL073598 Core 3: 3D Imaging and Computer Modeling of the Respiratory Tract, 9/1/04-8/31/09; as well as prior support from NIH/NCRR P41 RR01243 Simulation Resource in Circulatory Mass Transport and Exchange, 12/1/1980-11/30/01 and NIH/NIBIB R01 EB001973 JSim: A Simulation Analysis Platform, 3/1/02-2/28/07.