IV is the medical term for intravenous injection, which means that the drug solution needed to treat a disease is pumped into a syringe of a certain capacity and pushed into the blood vessels by hand or with a special microinjection pump. The syringes used for intravenous injection are 5ml, 10ml, 20ml, 30ml, 50ml, 100ml, etc. Depending on the amount of medication to be injected, different syringes are selected. For example, when rescuing a patient with hypoglycemia, assuming that 40ml of 50% glucose injection needs to be injected intravenously first, the nurse will pump 40ml of glucose solution into a 50ml syringe and push the medicine into the blood vessel by hand. Another example is if the patient’s blood sugar is very high and requires continuous, longer-term insulin control, and requires microscopic, uniform, and accurate doses, then a microinjection pump is used to pump insulin into the blood vessels instead of pushing it manually.