Peripheral Intravenous Cannulation

Cannulation is the process whereby a cannula (a small hollow plastic tube) is inserted into and kept inside the vein for a period of time. You may also hear a peripheral intravenous cannula being referred to as an IV, a cannula, or a drip.

Why is it done?

The purpose of cannulation is to give the patient fluids and/or medication. Directly administering fluids and medications into the vein, means that the patient will receive the effects of the treatment much more quickly than by any other route. A patient may also need a cannula in case of an emergency.

This image were sourced from Medline Plus

What is done?

A tourniquet is placed on the arm for a short time so that the veins become easier to see, feel and cannulate. The skin is cleaned with an anaesthetic and the clinician, wearing sterile gloves, feels for the vein and then inserts the cannula. A cannula is usually inserted into the arm or back of the hand and has a sharp needle inside so that the patient’s skin can be pierced easily. Once the cannula is inside the vein, the sharp needle is removed, leaving a small, hollow, plastic tube behind - this is the cannula. The only thing you will be able to see outside the skin is the hub or cap of the cannula; this is where the fluid and/or medications are inserted into the cannula. A sterile dressing is then applied and an intravenous infusion of fluids +/- drugs may be attached.

Does it hurt?

Generally the only pain experienced is when the needle is first inserted into the skin, and this is brief. At times some medications or fluids may cause a little pain or sting, and this is sometimes an indication that it is time for the cannula to be removed, and a new one inserted if required.

Care of

• The sterile dressing should be kept clean and dry and therefore must be covered when showering or bathing
• A cannula should be replaced every three days and most hospitals have a policy regarding how often the cannula should be changed.
• It is important that the cannulae and intravenous fluid giving set are not interfered with as this may lead to infection or the incorrect dose of a medication.

What are the risks?

These include:

• A haematoma - occurs when blood leaks out through the hole in the vein causing swelling and bruising (happens occasionally);
• Catheter embolism - this happens when part of the plastic cannula may have been broken off by the needle, and this part of the catheter travels through the blood stream (rare);
• Cannula tissues - this happens when the cannula makes its way out of the vein and into the surrounding tissue causing fluid to accumulate in the tissue. This may occur when the cannula has been bumped or pulled at (happens occasionally);
• Infection - this can happen when the cannula is left in too long, or when the cannula insertion site is handled without washing the hands first (happens occasionally).

All Intensive Care interventions and procedures carry a degree of potential risk even when performed by skilled and experienced staff.

Any questions?

If you have any more questions about catheterisation, you can ask one of the many doctors and nurses looking after your friend or relative.

The information contained on this page is general in nature and therefore cannot reflect individual patient variation. In addition it reflects Australian intensive care practice which may differ from other countries. It is meant as a back up to specific information which will be discussed with you by the Doctors and Nurses caring for your loved one. ICCMU attests to the accuracy of the information contained here BUT takes no responsibility for how it may apply to an individual patient. Please refer to the full disclaimer.