Model number

Simple one compartment model with pressure source and constant compliance.


This simple model demonstrates a single compartment with compliance. The compartment changes its volume as pressure source is applied. Flow resistance is set to zero and initial resting volume is set to a user defined value. This is an introductory demonstration of JSim environment and basic notions in airways dynamics. The pressure-volume relationship is given by simple equation. The model can be considered as a ventilator. P is the driving pressure, P0 is the background pressure, Com is the compliance, and V and Vr are instantaneous volume and volume at rest, respectively. This model demonstrates the deficiency of the widely used simple pressure-volume relationship that is defined by the first equation.

fig 1

Figure Legend: P: Pressure (forcing), P0: ambient (background) Pressure, Com: Compliance


The governing equations are



where V is the volume, Vr is the volume when P=P0, and Flow is the change in volume.

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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Key terms
compartment model
Respiratory System
Respiratory Mechanics

Please cite in any publication for which this software is used and send one reprint to the address given below:
The National Simulation Resource, Director J. B. Bassingthwaighte, Department of Bioengineering, University of Washington, Seattle WA 98195-5061.

Model development and archiving support at 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.