During thoracic surgical procedures, while ventilating with a protective tidal volume, an open lung approach consisting of a recruitment maneuver followed by an individualized positive end-expiratory pressure (PEEP) titrated to best respiratory system compliance (Open-lung PEEP, OL-PEEP) would decrease driving pressure. To test this hypothesis, we performed a multicenter observational study in 17 Spanish teaching hospitals of patients undergoing one lung ventilation (OLV). In addition, we analyzed the association between the driving pressure and the prevalence of postoperative pulmonary complications (PPCs), and finally the association between the individualized PEEP and relevant patient preoperative or intraoperative variables.