IntroductionDuring and after coronary artery bypass grafting, a decline in multifactor lung function is observed. Due to this fact, some patients may benefit from non-invasive ventilation after extubation targeting lung expansion and consequently improved oxygenation.ObjectiveTo test the hypothesis that higher levels of positive end expiration pressure during non-invasive ventilation improves oxygenation in patients undergoing coronary artery bypass grafting.MethodsA randomized clinical trial was conducted at Instituto Nobre de Cardiologia in Feira de Santana. On the first day after surgery, the patients were randomized: Group PEEP 10, Group PEEP 12 and Group PEEP 15 who underwent non-invasive ventilation with positive end expiration pressure level. All patients were submitted to analysis blood pressure oxygen (PaO2), arterial oxygen saturation (SaO2) and oxygenation index (PaO2/FiO2).ResultsThirty patients were analyzed, 10 in each group, with 63.3% men with a mean age of 61.1±12.2 years. Mean pulmonary expansion pre-therapy PaO2 was generally 121.9±21.6 to 136.1±17.6 without statistical significance in the evaluation among the groups. This was also present in PaO2/FiO2 and SaO2. Statistical significance was only present in pre and post PEEP 15 when assessing the PaO2 and SaO2 (P=0.02). ConclusionBased on the findings of this study, non-invasive ventilation with PEEP 15 represented an improvement in oxygenation levels of patients undergoing coronary artery bypass grafting.