Patient Preparation.The ultrasound examination is most effective if the patient has been NPO for at least 6 hours. This allows the biliary system to be distended and easily imaged by the sonographer. When a patient is fasting there is a a decreased opportunity for gas to accumulate within the colon; gas prohibits the passage of the sound and thus limits visualization of abdominal structures. If the patient is able to consume liquids and the pancreas is not well-visualized, the administration of 32 oz. of water may be given to fill the stomach and duodenum to better delineate the pancreas.
The kidneys are best imaged when the patient is fully hydrated, therefore no patient preparation is necessary when only the kidneys are examined. Full hydration will also enable the sonographer to image the distended urinary bladder.
Patient Position.The position of the patient for the general abdominal scan is usually supine for the initial images. The patient is then rolled into various degrees of obliquity to better demonstrate the biliary system, pancreas, liver, kidneys, or spleen. If the scanning plane is oblique, the sonographer should indicate the change of position on the documented image without specifying the exact degree of obliquity. The same would apply if the patient were in a lateral, upright, or prone position.