There is generally no problem with air entering the IV, and the amount of air that enters inside the blood vessels as a result of a general infusion is relatively small, in the range of 1-2mL. The blood vessels of the human body have air entering the body due to the action of blood pressure, which changes the air into small bubbles that can be eliminated directly inside the bloodstream. Currently applied infusion sets are precision infusion sets with a disk-shaped device underneath to expel air bubbles. Under normal circumstances, if there is a small amount of air bubbles in the infusion tube, they can also be expelled through the disk device and will not enter the blood vessel. If a larger amount of air enters the blood vessels, more than 10 ml or more, it may cause discomfort. Air entering the body and entering the heart with the blood will cause a large amount of blood froth, increasing the volume, which will reduce cardiac output and cause tissue ischemia and hypoxia. More than 10ml under normal circumstances may cause air embolism. So you need to watch closely during the infusion and try not to let air enter the blood vessels.