Modeling the lung: A rheological question – Part 1

Rheology is a branch of physics that studies the deformation and flow of matter and provides the mathematical framework for analyzing pulmonary mechanics. Rheological theory views the lung as a viscoelastic body that exhibits both elastic and viscous properties, implying that its response to mechanical forces depends not only on the magnitude of the force but also on the speed and frequency with which it is applied. It provides an understanding of how elasticity, resistance, and viscosity contribute to respiratory mechanics and ventilator-induced lung injury Monitoring respiratory mechanics in the Intensive Care Unit (ICU) has traditionally been based on the respiratory system equation of motion, which assumes first-order or linear behavior, characterized by constant static resistance and elastance (or its reciprocal, compliance). However, the physiology of the lung parenchyma is far from being a purely elastic system. This publication represents the first installment of three about lung modeling. Keywords: Lung modelling, Hysteresis, Viscoelasticity, Rheology