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.