Low-Order Mechanistic Models for Volumetric and Temporal Capnography: Development, Validation, and Application.

Objective: Develop low-order mechanistic models accounting quantitatively for, and identifiable from, the capnogram - the CO concentration in exhaled breath, recorded over time (Tcap) or exhaled volume (Vcap).

Methods: The airflow model's single "alveolar" compartment has compliance and inertance, and feeds a resistive unperfused airway comprising a laminar-flow region followed by a turbulent-mixing region. The gas-mixing model tracks mixing-region CO concentration, fitted breath-by-breath to the measured capnogram, yielding estimates of model parameters that characterize the capnogram.