Introduction to IVs We have already learned that IV stands for intravenous, or an injection that is given directly into the vein. We have a limit of 3 mL of fluid for adults when giving them subcutaneous or intramuscular injections because more than that will cause problems in the tissue surrounding the injection site, but because an IV injection goes directly into a patient's vein, the only limit on the amount of fluid that can be administered via an IV is the limit on the amount a fluid a person's body can consume without receiving more liquid than the body can absorb or excrete which can lead to medical problems such as heart failure, high blood pressure, and excessive fluid in the lungs. The safe range of daily fluid intake will vary based on the patient's condition, size and age, as several diseases such a heart failure, kidney failure, and diabetes, for example, can require that a patient limit their daily fluid intake. For example, a kg healthy adult, should get mL per day of fluid, or 3. This is a lot of fluid compared to the amount that we can give using other parenteral routes of administration.