Lines and cannulas

Intravenous lines

“IV” stands for “intravenous” and means ‘within a vein'. IV lines are placed into a vein to give fluids and medications directly into the bloodstream. Patients on ICU will have many IV lines.


When a doctor or nurse wants inserts a smaller IV line, they begin with a “cannula”. This is a small plastic tube with a needle inside it. The needle is inserted into the vein with the cannula wrapped around it. The needle is then removed and the cannula stays in the vein. A ‘line' is then attached to the cannula. Infusions (fluids and medications) can then be given through the IV line.

Small IV lines

Small IV lines can be placed in small veins in the hands, arms or feet.

Large IV lines

Central venous catheter (CVC)
Larger IV lines are sometimes needed to give multiple medicines, nutrition or special types of medicines. This type of large IV line is called a “central venous catheter (CVC)”. The word “catheter” means a flexible tube. Usually people associate the word catheter with a “urinary catheter“. A central venous catheter (CVC) is different because the catheter is going into a large vein. The vein chosen is near the heart, neck or groin area.

Peripherally inserted central catheter (PICC)
A peripherally inserted central catheter or “PICC” line (pronounced “pick”) is another type of IV line. It is very long and flexible. It is usually placed into a vein in the inner elbow area. It is then threaded through so the tip sits in a larger vein. A PICC line can be used for many weeks/months. This is helpful if someone is on antibiotics for many weeks or if they need nutrition through the bloodstream.

Arterial lines

This is a plastic tube inserted into an artery. The artery usually chosen for this is in the wrist, the neck or the groin. An arterial line measures the blood pressure with each beat of the heart. It also allows blood tests to be taken from a small tap.

Related topics

This topic was reviewed by an intensive care medicine specialist in July 2022.

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