Obesity is currently one of the most serious public health problems. Its prevalence is increasing sharply in recent decades, even in developing countries, leading to global epidemiology condition. Metabolic syndrome (MS) consists of an association of metabolic and cardiovascular disorders including central obesity, insulin resistance, dyslipidemia and hypertension in the same patient. Obstructive sleep apnea (OSA) is a common clinical condition in more than 60% patients with MS. It is still controversial in the world scientific literature whether treatment of OSA with Noninvasive Positive Pressure Ventilation (NPPV) in severely obese patients with and without MS is effective. The NPPV effectively reverses hypoxemia in patients with OSA, therefore justified the hypothesis that NPPV will reduce insulin resistance, ghrelin and resistin and raise adiponectin levels in a group of severely obese individuals with and without MS undergoing bariatric surgery. Objectives: To investigate the effects of Noninvasive Positive Pressure Ventilation on inflammatory markers, sleep, pulmonary function, BMI reduction and health related quality of life in severe obese patients with and without metabolic syndrome undergone to bariatric surgery. Methods/Design: Will participate severe obese patients with and without MS, screened from the Bariatric Surgery Service of Santa Casa de Sao Paulo. The inclusion criteria are patients with morbid obesity grade III, with an indication of bariatric surgery and who have agreed to the study, signing an informed consent. Subjects with BMI above 55 kg / m², clinically significant or mental health concerns unstable, an unrealistic target postsurgical weight and/or unrealistic expectations of the surgical treatment will be excluded. Patients will use the NPPV pre and post bariatric surgery. The evaluation protocol will consist of clinical history, vital signs, anthropometric data, clinical analysis of blood and adipose inflammatory markers, lung function tests, polysomnography, sleep scales, cardiovascular risk and quality of life questionnaires. Patients will be evaluated before and after bariatric surgery, 90, 180 and 360 days.