[Study of ventilatory mechanics - its application to artificial ventilation (author's transl)]

Study of ventilatory mechanics implies collection of input variables (stresses estimated by pressures) and output variables (strains), from which the parameters (compliance, resistance, etc.) of a model reproducing the functioning system can be computed. From this point of view, patients under artificial ventilation show a twofold difficulty: the one is the collection of variables, very difficult in consideration of the patients' precarious state, the other the type of the model: the first order linear model, used for lack of better solution, can be criticized, on the one hand by severe pulmonary changes in these patients, and by the special mode of applying constraints during artificial ventilation on the other. All these facts explain the methodologic and theoretical difficulties encountered in ventilatory mechanics analysis in resuscitation, which actually leads to the expression of one parameter as representative of the pulmonary parenchymal elasticity: the static compliance, and to the determination of the balancing point of the system: the functional residual capacity.