After lung resection surgery, patients usually receive a postoperative pleural drain. Prolongated alveolar air leak (PAAL) is a frequent complication after lung surgery (6 to 26% of patients), defined by the European Society of Thoracic Surgeons (ESTS) as a duration of drainage greater than or equal to five days. PAAL is most often due to prolongated bubbling of the drain. Prolonged drainage is a leading cause of prolongated hospital stay, increasing care costs.

The risk of prolongated drainage can not be predicted with sufficient accuracy. Existing risk scores for PAAL do not take into account the intraoperative ventilatory leakage (IVL). IVL is a parameter displayed on the ventilator (anaesthetic machine that make the patient breathing during surgical procedure). There is new evidences suggesting that IVL could predict the risk of PAAL after lung resection surgery, but these data have to be supplemented by a well conducted prospective study.

Inclusion criteria:

• To be 18 years old or older
• To be of French nationality or native from an European country affiliated to the French health care system
• To be scheduled for pulmonary resection surgery by videothoracoscopy or thoracotomy in the center of the study

Exclusion criteria:

• Patient minor, or major under legal protection, or enable to give consent
• Refusal or consent withdrawal
• No pulmonary resection or no pleural drain at the end of the surgical procedure (decided by the surgical team)
• Postoperative pleural fistula

All consecutive patients scheduled for pulmonary resection surgery by videothoracoscopy or thoracotomy (including pulmonary wedge resection, segmentectomy, lobectomy, bilobectomy, pneumonectomy).