Peripheral venous pressure determines whether the upper and lower vena cava are under pressure, whether the heart has impaired blood displacement and whether there are changes in blood volume, and can assist in the diagnosis of right heart failure, pericardial effusion, constrictive pericarditis, mediastinal tumors and superior vena cava obstruction syndrome. The patient needs to rest quietly for 15 minutes before the measurement, relax and breathe evenly and freely. The manometry tube is flushed with anticoagulant and saline before the measurement, and the catheter must be kept open during the measurement to avoid wrong diagnosis. The manometry tube must be kept in the vertical position 0 point, at the same level with the center of the right atrium, if the body position changes, the center should be adjusted for the measurement.