In clinical practice, a transfusion of more than 1.5 times the patient’s blood volume in a 24-hour period, or a transfusion of 1/2 the blood volume in an hour, is called a massive transfusion, and is commonly seen in trauma, hepatectomy, organ transplantation, obstetrical and gynecological transfusions, and severe chemical tract bleeding. 3. hypokalemia. 4. decreased body temperature, especially in patients transfused with more than 1000 mL of blood in a short period of time. 5. microtethering of blood vessels. 6. citrullosis, acidification of blood, etc. Therefore, heart rate, respiration, blood, intrapulmonary rales, jugular venous filling, etc. should be closely observed during massive transfusion, and it is better to do dynamic monitoring of central venous pressure, and to terminate the transfusion in time when it is finished to avoid air tethering.