Inclusion Criteria:  Outpatient colonoscopy under moderate sedation Colonoscopy Indications: Screening  Exclusion Criteria:  More than one sedation procedure scheduled same day Allergy to ondansetron Past PONV requiring scopolamine patches Diagnoses: ESRD, heart failure, cirrhosis, long QT syndrome Patients requiring fluid restrictions, such as dialysis patients Post-procedure NPO requirements, such as procedure-related NPO status (stent placement, pneumatic dilation, etc.) or second procedure in another location High Fall Risk Patients Adults unable to consent Pregnant patients