IV
Meaning of IV: Bypassing the gut entirely means the whole amount arrives at once, which is an advantage in an emergency and a hazard in an error.
Definition of IV
IV is short for intravenous, meaning into a vein. The abbreviation names both the route and the line used for it: a needle or thin flexible catheter placed in a vein so that fluids, medicines, nutrition or blood products can be delivered straight into the bloodstream rather than absorbed from somewhere else.
Why give something into a vein?
A swallowed medicine has to survive stomach acid, cross the wall of the intestine and then pass through the liver, which breaks down part of it before the rest of the body sees any. The share that survives is unpredictable and varies between people and with food. An intravenous dose skips all of that: the full amount enters the circulation, and it does so within seconds rather than over an hour. That matters when a treatment is needed urgently, when the amount reaching the blood has to be exact, when a drug would be destroyed in the gut, or when a person cannot swallow. The route is also the only practical way to give large volumes of fluid, and the only way to give a blood transfusion.
What kinds of access are used?
| Type | Where it sits | Typical use |
|---|---|---|
| Peripheral line | A small vein in the hand, forearm or elbow crease | Short courses of fluid or medicine, changed every few days |
| Midline | Advanced further up the arm without reaching the chest | Treatment over a few weeks |
| Peripherally inserted central catheter | Entered at the arm, with the tip in a large vein near the heart | Prolonged antibiotics, nutrition, chemotherapy |
| Implanted port | A reservoir under the skin of the chest joined to a large vein | Repeated access over months, as in central venous access for cancer treatment |
The choice depends on how long access is needed and on what is being given, since concentrated or irritating solutions damage small veins.
What can go wrong?
Fluid can leak out of the vein into surrounding tissue, producing swelling and, with certain drugs, tissue damage. The vein wall can become inflamed and tender. Any device crossing the skin is a route for bacteria, and infection reaching a central line can enter the bloodstream directly. Giving fluid faster than the circulation can handle causes overload. These are the reasons a catheter site is inspected regularly and lines are removed once they are no longer needed.
Also known as
Used in a sentence
IV fluids were started to address the patient's dehydration.
Good to know
Medication given IV reaches the bloodstream directly and generally acts faster than the same medication given orally, intramuscularly, or subcutaneously, a distinction that affects how urgently a treatment can take effect.