Lung Modeling Pressure-volume Curve Hysteresis Surface Tension Lung Compliance Internal Variables Pulmonary Surfactant

External authors:

• Nibaldo Aviles-Rojas ( Pontificia Universidad Catolica de Chile )

Abstract:

Surface tension arising in the air-liquid interface of alveoli is a fundamental mechanism lung physiology that explains lung recoil and hysteresis during breathing. However, pulmonary surface tension is typically neglected in continuum models of the lungs, possibly due to complex multiscale physicochemical nature. In this study, we formulate a poromechanical framework that incorporates the effect of surfactant-dependent surface tension in porous for the prediction of lung hysteretic response. Using an internal variable formalism, we the Coleman-Noll procedure to establish an expression for the stress tensor that includes surface tension akin to the Young-Laplace law. Based on this formulation, we construct non-linear finite-element model of human lungs to simulate pressure-volume curves and response during mechanical ventilation. Our results show that surfactant-dependent tension notably modulates pressure-volume curves and lung mechanics. In particular, our captures the influence of surfactant dynamics on lung hysteresis and compliance, predicting the transition from an insoluble reversible regime to a dissipative one governed by Langmuir kinetics. We envision that our continuum framework will enable lung simulations surfactant-related phenomena are directly considered in predictions, with important applications to modeling respiratory disease and lung response to mechanical ventilation.