Gastroplasty and Electrical Impedance Tomography

Patients in the Experimental Group will be submitted to ARM, immediately after abdominal desinflation of the pneumoperitoneum (PNP). The ARM will be performed with PEEP of 15 cmH2O for thirty seconds, 20 cmH2O for thirty seconds, 25 cmH2O for thirty seconds, 30 cmH2O for one minute and a inspiratory plateau pressure of 15 cmH2O above PEEP, totaling two minutes and thirty seconds.The data of the TIE will be continuously recorded and the hemodynamic and respiratory function variables such as heart rate (HR), respiratory rate (RF), mean arterial pressure (MAP), peripheral oxygen saturation (SpO2) and final gas expiratory pressure carbon dioxide (PETCO2) will be recorded in several moments: immediately after the monitoring, and the patient is still on spontaneous ventilation, 5min after orotracheal intubation, after the installation of the pneumoperitoneum, before and after the execution of the MRA and in the Post-OP, in the first 24h, along with new lung function tests.

Immediately after intubation, patients will undergo mechanical ventilation with the ventilator (Dixtal DX 5020) in volume controlled mode with an ideal tidal volume of 7 ml / kg body weight, a set frequency to maintain a carbon dioxide of 35-42 mmHg, and an inspiratory / expiratory ratio of 1: 2. The inspiratory oxygen fraction (FIO2) will be 0.5.