Determination of total respiratory compliance during artificial ventilation

The main objective of the study presented in this thesis has been the investigation of mechanisms related to the decrease in airway pressure during an inspiratory pause in mechanically ventilated subjects. In particular, we have paid attention to two of these mechanisms, i.e. viscoelasticity and the in:fl.uence of continuous gas exchange on lung volume. We aimed at estimat-_ ing the errors in the determination of CRs when assuming the pressure after an inspiratory pause of 1.5 s to be equal to 'the' static recoil pressure of the respiratory system, which is a common assumption in clinical practice [57,90,98]. In addition we aimed at an evaluation of other methods for the estimation of CRs during mechanical ventilation. This study was performed in animals for reasons oflarge series of observations in each subject in order to evaluate the accuracy and the reliability of a diversity of standardized methods for the estimation of CRS· We have used piglets.