**3. Summary**

Perioperative ventilation support is indispensable for patients under thoracic surgery. Inadequate settings of ventilation support may cause a number of problems, including hypoxemia, shear stress trauma, barotraumas and pulmonary edema. A suitable PEEP level maintains dependent lung regions open and thereby improves oxygenation and reduces the risk of inflammation. The selection of optimal PEEP is still under debate. We propose to combine indices of lung mechanics, blood gas analysis and imaging techniques to titrate PEEP. Besides, application of PEEP should be complemented with other strategies (e.g. low tidal volume, appropriate body positioning, recruitment maneuver), to achieve the best outcome of the patient.
