60 morbidly obese patients which planned sleewe gastrectomy procedures under general anestesia (ASA 2-3 status) were included in this study. Patients were devided into 2 groups which was ventileted with no positive end expiratory pressure(Group 5PEEP n=30), and 5 cmH2O positive and expiratory pressure (Group ZEEP n=30). All the patients were right hand dominate.