Effect of NPO Time and Type of Food Intake on Preoperative Residual Gastric Content and pH

This study is a prospective observational cohort study which will be conducted in 2 parts including preoperative and intraoperative periods. * Preoperative period, patients' demographic information will be collected along with NPO history including times, type ,amount of preoperative fluid/ food intake and patients' anxiety score. * Intraoperatively, at the beginning of EGD procedure, total volume of intragastric content(ml) and gastric acidity will be measured. We plan to offer participation to all patients or parents of patients' ages 0-17 years who are scheduled for EGD at GPU, BCH Longwood campus and are fluent in English. A brochure describing our study in English will be given to patients or their families on the day of surgery. If the patient or family agrees to participate in this study, the study will be provided in the GPU theaters.