The foaming test is mainly a test to detect unclosed foramen ovale. The foaming test refers to the use of saline mixed with bubbles into a human vein, and if there is unclosed foramen ovale, the bubbles will enter the left heart from the right heart, and from the left heart they will enter directly into the blood vessels of the brain, which may cause the patient to experience dizziness and headache. The purpose of the foaming test is to detect the positive rate. If the foaming test is grade III or IV or higher and is positive, there is an indication for surgery and requires minimally invasive interventional treatment with interventional closure of unclosed foramen ovale or open chest for examination and surgical treatment of unclosed foramen ovale.