Patients with small pulse pressure are most often seen with shock, myocardial infarction, cardiac insufficiency, pericardial tamponade, and hyperaldosteronism. Other organic pathologies that cause a decrease in pulse pressure difference include pericardial effusion, constrictive pericarditis, severe mitral stenosis, and aortic stenosis. Therefore, when the pulse pressure difference is found to be significantly reduced, various organic pathologies should be ruled out first, and then a chest fluoroscopy is required when going to the hospital: I. Precautions: During the examination: the subject must remove all items that can cause shadows on the chest, such as plastered ointments, footsteps, necklaces, items in the chest pocket, and women’s hair should be coiled high. Unsuitable groups: Children should be cautious to do chest X-ray. Second, the examination process: 1, the subject should be upright during the examination, the chest close to the fluoroscopy screen, check the lateral position, the subject’s arms up to hold the head, the upper arm close to the root of the ear. 2, during the examination, the patient should take a deep breath. 3, serious patients or the elderly and frail can not stand, you can do the examination in the lying or sitting position. Three, the index interpretation results: Normal The size and shape of the heart, lungs and diaphragm are normal. Or: symmetrical chest corridor, clear texture of both lungs, normal structure of hilar shadow, small heart shadow, mediastinum centered, smooth bilateral diaphragmatic surface, sharp bilateral rib-diaphragm angle, no abnormality in the supra-diaphragmatic ribs. Abnormalities Fluoroscopy shows abnormalities.