Lung/airway dynamic model using ABM elements and PSPICE

The aim of the present work is the construction of a nonlinear dynamic model of lung/airway mechanics using generic instead of specific software, in an attempt to offer an open simulation environment. Based on the analogy between pneumatic and electric magnitudes, an electrical equivalent circuit of the lung/airway mechanics is derived. Then, the nonlinear circuit elements are constructed by means of the powerful Analog Behavioral Modeling (ABM) building blocks and the system is solved using PSPICE. Five lumps are defined: two capacitors (elastances) corresponding to lung and collapsible airway segment and three resistors, corresponding to lung, collapsible airway segment and upper airway. The model does not attempt to mimic any particular system by adjusting a given set of parameters but instead to provide a tool to explore the relationship between a given parameter or set of parameters and the system response, in particular for the Forced Vital Capacity (FVC) maneuver.