Inclusion Criteria:  paediatric patients aged 6-12 years old ASA physical status I and II scheduled for elective surgeries the anticipated duration of 30-60 min  Exclusion Criteria:  parents' refusal overweight or obesity expected difficult airway management increased abdominal pressure diabetes mellitus congenital diseases GERD or esophageal disease uncooperative patients, mental retardation or neurological disease upper airway surgeries.