Ultrasound examination of the upper abdomen, such as the liver, especially the gallbladder, bile duct, pancreas and adrenal glands, renal artery, left renal vein, abdominal vessels, retroperitoneum, and upper abdominal masses, requires examination after fasting, usually starting with fasting after dinner the day before and examining on an empty stomach the next morning to ensure bile filling in the gallbladder and bile duct and to reduce interference from gastrointestinal food and gas; otherwise, the examination results may be greatly affected. The quality of ultrasound images in these areas is easily disturbed by intestinal gas, so patients with bloating or constipation are advised to take digestive drugs before the examination to help defecate or use corky or some light relief agents to help defecate. In addition, the transesophageal echocardiogram must be scheduled in advance and the doctor will instruct the patient to fast on the day of the examination. The patient should also bring the results of the transthoracic cardiac ultrasound so that the examining physician can quickly understand the condition and target it during the transesophageal examination. Since this test is semi-invasive and carries some risk (usually not high), it requires the family and the patient to sign the informed consent form for the test and be accompanied by a family member.