Intraoperative hemodynamic optimization decreases postoperative complications and length of stay in high risk patient. Therefore, continuous monitoring of cardiac output (Qc) is recommended to guide fluid management. Thoracic bio-reactance is a recent technique that allows cardiac output non-invasive monitoring. However, additional clinical validation studies in humans are required to better define the typologies of patients for whom this monitoring could be proposed routinely. Lung surgery is defined as an intermediate or high risk surgery regarding postoperative cardiac complications. However, surgical patients rarely benefit from continuous monitoring of cardiac output, the available methods being considered too invasive or insufficiently reliable in daily practice. Thoracic bio-reactance (Non Invasive Cardiac Output Monitor (NICOM) Starling SV) has not been studied in this subgroup of clinically relevant patients.

Inclusion Criteria:

• Adult patients
• Scheduled in Louis Pradel hospital operating theater (Lyon University Hospital) for elective Lung surgery (lobectomy, bilobectomy or pneumonectomy); by thoracotomy and / or thoracoscopy.
• Having stated their non opposition to be part of this protocol

Exclusion Criteria:

• Pregnant women ;
• unemancipated minors;
• Persons unable to express their consent;
• Patients with contraindications to the placement of an oesophageal Doppler probe
• Patients with suspicion of pathology or oesogastric lesion (dysphagia, diverticulum, stenosis ...)
• Patients known for stage 2 or higher oesophageal varices
• Patients with a history of significant mediastinal irradiation, or bariatric surgery.
• Patients who have been treated in a therapeutic trial within 30 days of enrollment or who wish to participate in an ongoing study that may interfere with this study.
• Persons benefiting from legal protection measures;
• Patients unable to understand study objectives or refusing to comply with postoperative instructions

- Adult patients scheduled in Louis Pradel hospital operating theater (Lyon University Hospital) for elective Lung surgery (lobectomy, bilobectomy or pneumonectomy); by thoracotomy and / or thoracoscopy.