Protective Ventilation With High Versus Low PEEP During One-lung Ventilation for Thoracic Surgery

One-lung ventilation (OLV) with resting of the contralateral lung may be required to allow or facilitate thoracic surgery. However, OLV can result in severe hypoxemia, requiring a mechanical ventilation approach that is able to maintain adequate gas exchange, while protecting the lungs against postoperative pulmonary complications (PPCs). During OLV, the use of lower tidal volumes is helpful to avoid over-distension, but can result in increased atelectasis and repetitive collapse-and-reopening of lung units, particularly at low levels of positive end-expiratory pressure (PEEP). Anesthesiologists inconsistently use PEEP and recruitment maneuvers (RM) in the hope that this may improve oxygenation and protect against PPC. Up to now, it is not known whether high levels of PEEP combined with RM are superior to lower PEEP without RM for protection against PPCs during OLV. Hypothesis: An intra-operative ventilation strategy using higher levels of PEEP and recruitment maneuvers, as compared to ventilation with lower levels of PEEP without recruitment maneuvers, prevents postoperative pulmonary complications in patients undergoing thoracic surgery under standardized one-lung ventilation.