This model is based on Lutchen et al. A nonlinear model combining pulmonary mechanics and gas concentration dynamics. IEEE Trans. Biomed. Eng. 29: 629-641, 1982
The model equations derived from mass and force balances describe the intrabreath dynamics of pressure, flow, volume, and gas species concentration after a step change in gas composition at the airway opening. This model has two parallel, perfectly mixed alveolar compartments connected to a single, constant-volume airway (dead space) in which no mixing occurs. There is a mixing point m at the junction of the two alveolar compartments and the conducting airway (see figure below). The gas that enters the airway opening during inspiration will reach the mixing point after the dead space is cleared. During expiration, until the dead space is cleared, the output concentration at the airway opening is the input concentration.
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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Lutchen KR, Primiano FP Jr, Saidel GM; Nonlinear model combining pulmonary mechanics and gas concentration dynamics. IEEE Trans Biomed Eng. 29(9):629-41, 1982.
Please cite https://www.imagwiki.nibib.nih.gov/physiome 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 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.