Non-invasive Assessment of Lung Recruitment in Morbid Obese Patients Undergoing Bariatric Surgery

This is a prospective study perform in 30 anesthetized morbidly obese undergoing bariatric surgery. Lung mechanics and volumetric capnography will be non-invasively assessed during laparoscopy. Esophageal pressure will be measured by an esophageal balloon to measure transpulmonary pressure. A lung recruitment maneuver will be done. The optimum level of positive end-expiratory pressure (PEEP) is defined as the PEEP level when transpulmonary pressure remains positive during the PEEP titration trial of the recruitment maneuver. Lung collapse is detected when transpulmonary pressure becomes negative. The behavior of the studied volumetric capnography and lung mechanics parameters will be compared with the reference transpulmonary pressure signal.