If a patient is unwell and goes to the hospital for saline treatment, if air enters the saline when it is hanging, the following situations may occur: First, if the air entering the saline is less than 5ml, there is no need to be too nervous because 5ml of air will be gradually absorbed through blood circulation in the blood vessels and will not cause too much harm to the human body. Second, if the air that enters is between 5ml and 10ml, the infusion should be stopped in time and the patient’s specific situation should be closely observed. Third, if the air entering with the saline is more than 10ml, effective treatment measures must be carried out at this time to avoid the patient causing air embolism and endangering life.