The measured central venous pressure blood pressure is less than the normal value of 0.49 kPa. The blood pressure in the right atrium and the large veins in the thoracic cavity is called the central venous pressure. The level of central venous pressure depends on the interrelationship between the ejection capacity of the heart and the amount of blood returning to the heart from the veins. If the heart has a high ejection capacity and is able to eject the blood returning to the heart into the arteries in a timely manner, the central venous pressure is lower. Central venous pressure is another indicator of cardiovascular function. Clinically, when treating shock with infusion, besides observing the change of arterial blood pressure, we also need to observe the change of central venous pressure. The normal range of central venous pressure is 4-12cmH2O, if the central venous pressure is low or has a tendency to decrease, it often indicates that the amount of infusion is insufficient.