A synthesis of the Otis, Mead, and Mount mechanical respiratory models

We propose a unified approach of the viscoelastic models introduced by Otis, Mead and Mount to describe the mechanical behaviour of the respiratory system. A single equation of motion is developed for these two-compartment models and solved in response to typical pressure and volume inputs. The analytic expression of the pressure response to rapid airway occlusion following constant flow inflation, and of the volume response to single breath following end-inspiratory pause are more particularly analysed. The lumped respiratory parameters derived from these responses are expressed as functions of the parameters characterising the constitutive mechanical elements of each model. Different combinations of respiratory models and of methods for measuring respiratory mechanics are examined. For each model, the physiological interpretation of the lumped mechanical parameters is summarised in terms of gas redistribution or tissue viscoelastic properties.