1. A method for determining optimised parameters for mechanical ventilation, MV, of a subject, comprising: a) obtaining data concerning a three-dimensional image of the subjects respiratory system, b) calculating a specific three-dimensional structural model of the subject's lung structure from the image data obtained in step a), c) calculating a specific three-dimensional structural model of the subject's airway structure from the image data obtained in step a), d) calculating a patient-specific three-dimensional structural model of the subject's lobar structure from the lung model obtained in step b), e) modeling by a computer, the air flow through the airway, using the models of the airway and lobar structure of the subject obtained in steps c) and d) at defined MV parameters; f) modeling by a computer, the structural behavior of the airway and the interaction with the flow, using the models of the airway and lobar structure of the subject obtained in steps b) and c) at defined MV parameters, and g) determining the MV parameters which lead to a decrease in airway resistance and hence an increase in lobar mass flow for the same driving pressures according to the model of step d), thereby obtaining optimized MV parameters.