Objective To investigate the effect of different PEEP levels on stroke volume variation (SVV) in patients with acute respiratory distress syndrome (ARDS) treated with mechanical ventilation for predicting cardiac pre-load and the changes of hemodynamics.Methods Thirty critical patients with ARDS met the new criteria in 2012 set at European Berlin were enrolled in this study with measured values (MV) in EICU from September 2012 to October 2013.The changes in SVV and cardiac output (CO) monitored with Vigileo system were determined at different selected PEEE levels of 5,7,9,11,13,15 mmHg.At the same time,MAP and CVP were measured.Results Variation of PEEP levels led to a significant changes in SVV,CO (P ＜ 0.01).However,there were no significant differences in MAP (P =0.933).Changes of SVV induced by high PEEP showed a S shape rise,but there were no differences between groups PEEP 5 and PEEP 7,and as well as between groups PEEP 13 and PEEP 15 (P ＜0.05).The changes of CO showed a downtrend decline with the increase in PEEP levels.When PEEP was set at 13 mmHg and higher,the value of SVV denoted pre-load insufficiency.When PEEP was set at 11 mmHg or higher,cardiac output decreased.CVP could not predict the changes of pre-load.Conclusion Increase in PEEP levels can significantly reduce the cardiac pre-load.SVV can be a useful indicator of the changes in cardiac pre-load induced by high PEEP,suggesting fluid replacement necessary in time.