The purpose of this study, a collaboration with Technische Universität Dresden, is to compare a strategy of using high PEEP (10 cmH2O) with recruitment maneuvers versus low PEEP (5 cmH2O) without recruitment maneuvers during thoracic surgery under standardized one lung ventilation with low tidal volume (5mL/kg predicted body weight) in adults. It is not known whether a strategy using high positive end expiratory pressure (PEEP) combined with recruitment maneuvers, or one using low PEEP without recruitment maneuvers better protects against postoperative pulmonary complications (PPCs) during one-lung ventilation with low tidal volume for thoracic surgery.