There is no absolute rule on the maximum number of ml of blood to be transfused at one time, and the choice depends on the different conditions of the patient. For routine treatment, about 1 unit or 2 units of red blood cells are transfused at a time, and the therapeutic amount is 170ml and 340ml; plasma is usually transfused at 200ml and 400ml; platelets are transfused at a time with 1 machine collected platelet, which is about 250ml. If a patient experiences acute massive blood loss in a short period of time, multiple blood components can be transfused at the same time, and there is no upper limit for the amount of each blood component to be transfused. For example, in acute maternal amniotic fluid embolism, or ruptured uterus hemorrhage, tens of thousands of milliliters of blood products can even be transfused at one time.