• The patient should have no food by mouth for 8 hours prior to the procedure when possible.
• Studies should be performed early in the day to minimize bowel gas interference.
• If medications cannot be withheld until after the exam, patient may take morning medications with a small sip of water.
• The patient should not chew gum or smoke the morning of the exam as this may increase swallowing of air.
• The effects of solid food, water and liquids activate the gut resulting in elevated velocities and increase in size of the vasculature. It should be noted that if the patient has eaten within 8 hours of the study, standard velocity criteria for determining stenosis are not relevant.