Modeling and Experimental Identification of Airway Oxygen Transport Dynamics During Mechanical Ventilation

This paper examines the problem of modeling the dynamics of oxygen transport through the endotracheal tube of a mechanical ventilator. Such modeling can be potentially valuable for ventilator control, patient monitoring, and estimating airway oxygen transport during experimental studies on hypoxia. The paper presents an airway sensing package that provides collocated measurements of oxygen concentration and total gas flow rate. In theory, multiplying these two measurements can provide an estimate of tracheal oxygen flow rate. Unfortunately, substantial differences in dynamics between the above two sensors necessitate a more sophisticated modeling and estimation approach. Towards this goal, the paper presents a dynamic model of advective tracheal oxygen transport that accounts for measurement dynamics and delays. Parameters of this model are estimated from a hypoxia experiment on a Yorkshire swine, leading to good fitting accuracy for oxygen concentration measurements.