Positioning and Gastric Aspiration in Ventilated Premature Infants

Inclusion Criteria: * Infants born between 28 and 32 weeks gestational age * postnatal age \> 72 hours * tracheally intubated and receiving conventional mechanical ventilation * feeding enterally more than 20 ml per day. Exclusion Criteria: * neurological insult in the form of perinatal asphyxia (pH \<7, base deficit more than 12, Apgar score at \< 3 at 5 minutes of life), intracranial hemorrhage grades 3 or 4 at 72 hours of age or periventricular leucomalacia * major congenital anomalies, or gastrointestinal anomalies such as tracheoesophageal fistula, or necrotizing enterocolitis , * receiving xanthine derivatives, H2 blockers, prokinetics, proton pump inhibitors or sedation