According to former study, Albaiceta et al .[sup][15] recruited ten ARDS patients to assess the differences in lung mechanics between ARDS from pulmonary (ARDSp) and extrapulmonary (
ARDSe) origin, the results found there is differences between ARDSp and
ARDSe lung mechanics are present in the P[sub]es-volume curve, but also in the P[sub]L-volume curve, therefore, in our physiological study, the sample size was 10 in each group.