Abstract: Abstract: Objective To investigate the effects of different values of PEEP on cardiac index (CI), stroke volume nvariation (SVV) and oxygen transport index (DO2I) in patients monitored by FloTrac/Vigileo system, and to provide some references for the hemodynamic management and improvement of oxygenation for patients. Methods Sixty patients scheduled for elective television (TV) auxiliary thoracoscope radical operation for esophageal cancer were included in this study. Data of CI, SVV and DO2I were observed by the FloTrac/Vigileo system. Changes of CI, SVV and DO2I were recorded after anesthesia induction and turn left side (T0), artificial pneumothorax with 0 PEEP after 5 minutes (T1), artificial pneumothorax with 5 PEEP after 5 minutes (T2), artificial pneumothorax with 10 PEEP after 5 minutes (T3), and artificial pneumothorax with 15 PEEP after 5 minutes (T4). Results Compared with T0, CI decreased and SVV increased significantly at T1, T2, T3 and T4（P＜0.05). Compared with T1, CI decreased and SVV increased at T4. DO2I increased at T2 and T3 compared with that of T1（P＜0.05). Conclusion PEEP may have a certain influence on CI and SVV in the process of operation. The values of 5- 10 PEEP can significantly improve oxygenation and have a less influence on hemodynamics, which can be appropriately used in clinical care.

Key words: positive-pressure respiration, FloTrac/Vigileo system, cardiac index, stroke volume variation, PEEP