In addition, Kalhan et al also evaluated factors associated with the choice of tidal volume and he reported that underuse of LPV may be related to clinicians' under-recognition of less severe cases of ALI, and their reserving of low-tidal volume ventilation for more severe cases, or both. However, the factors such as comorbidity and pathophysiological change associated with underuse of lung protective ventilation strategy are not clear. We perform a prospective single-center study to investigate the factors associated with the use of lung protective ventilation strategy (LPV) in ALI/ARDS patients in ICU