CVP is the central venous pressure, which represents the pressure in the upper and lower vena cava of the right atrium. The normal value of CVP is 5-12cmH₂O. If the CVP is less than 5cmH₂O, rehydration should be performed, especially for surgical procedures. For patients who are fasting and drinking after surgery, patients with low CVP or patients in shock, rehydration should be performed clinically for these patients. If the CVP is too high, >12cmH₂O, it is necessary to consider excessive volume and control the fluid input, as well as to use diuretics appropriately according to the patient’s condition.