Obesity is a non-communicable chronic disease of multifactorial, involving biological, historical, ecological, economic, social, cultural and political. Currently, bariatric surgery is considered an effective method of refractory obesity treatment, and only severe obesity effective treatment that leads to reduced long-term weight. It is well documented in the literature regarding the association of abdominal surgery and the incidence of respiratory complications and its main characteristics are: atelectasis, pneumonia, respiratory dysfunction and pleural effusion. All these respiratory complications can be minimized or avoided with the use of a respiratory therapy care protocol, since the pulmonary atelectasis is considered the main cause of complications. An arsenal of resources to physical therapy lung expansion, among these, the application of positive pressure through a valve EPAP (Expiratory positive airway Pressure) and the use of noninvasive ventilation, and aims to prevent and / or improve the complications resulting from postoperative. The electrical impedance tomography (EIT) is an alternate to allow assessment of the respiratory system, without suffering the same interference conditions of patients, such as pain and bed rest. TIE consists of a method that measures passively regional lung ventilation. The aim of this study is to compare the effects of the application of EPAP and NIV on pulmonary ventilation we post bariatric surgery. This is a randomized controlled trial where patients will be divided into two groups: EPAP and NIV and assessed by spirometry, manometer and TIE. The techniques will be applied in the 1st and 2nd postoperative day where they will be evaluated before, during and after the application of the techniques.

Inclusion Criteria:

• Patients undergoing bariatric surgery, of both sexes and aged between 20 and 50 years.

Exclusion Criteria:

• severe lung disease;
• patients with congestive heart failure (NYHA Class III or IV);
• coronary artery disease;
• presented hemodynamic instability (MAP <60 mmHg) or arrhythmias during the performance of techniques, plus any contraindications to perform the BS techniques, EPAP and NIV to consider: Trauma / facial injury that prevents the attachment of the mask, extreme anxiety, hypotension and lack of patient cooperation.