Vascular access

Inserting a device, such as a catheter, into arteries and veins is one of the most common medical procedures. These devices are called vascular access devices.

Anyone in hospital who is seriously ill will have one or more vascular access devices inserted. These allow medicines and fluids to be given quickly. These devices may also be inserted if there is a high number and volume of medicines that needs to be given.

This page gives you a summary of the types of vascular access devices that may be inserted in people who are in the intensive care unit (ICU).

Cannula

This is also called a peripheral intravenous cannula, a PIVC or a drip.

What is a cannula?

A cannula is a thin short hollow plastic tube that is inserted into a vein for a short period of time.

Why is a cannula put in?

Cannulas are used to give fluids and/or medicines directly into the vein. This means that the person will get the effects of the treatment more quickly than if taken by mouth.

A cannula is commonly inserted when a seriously ill person is being admitted to the emergency department. This is so that they can receive life-saving treatment quickly until they can be stabilised.

How is it put in?

The cannula is inserted in a vein in the arm or back of the hand. It has a sharp needle inside so that the patient’s skin can be pierced easily. Once inserted, the only thing you will be able to see outside the skin is the hub or cap of the cannula, which is usually then attached to tubing through which medicines and fluids are given.

Does it hurt?

Generally, the only pain experienced is when the needle is first inserted into the skin. This pain shouldn’t last long. At times some medicines or fluids may sting or cause a little pain. If the pain lasts for a long time, this might be a sign that the cannula needs to be removed or replaced with a new one.

What are the risks?

The risks of inserting a cannula include:

• haematoma – this happens if blood leaks out through the hole in the vein into the surrounding tissue causing swelling and bruising (this happens occasionally)
• cannula tissues – this happens when the cannula makes its way out of the vein and into the surrounding tissue causing fluid to build up in the tissue. This may happen when the cannula has been bumped or pulled at (this happens occasionally)
• infection – this can happen when the cannula is left in too long, or when the cannula is handled without washing the hands first (this happens occasionally)
• catheter embolism – this happens if a part of the cannula gets broken off by the needle and travels through the bloodstream (this is rare).

It is important that the cannula and intravenous fluid-giving device are not interfered with, as this may lead to infection or the wrong dose of a medicine being given.

Central line

This is also called a central venous catheter or a CVC. A line that is inserted near the elbow can also be called a peripherally inserted central catheter, or PICC.

What is a central line?

A central line is a long fine catheter with an opening (sometimes multiple openings) at each end. It is used to give fluids and medicines directly into the bloodstream.

The central line is inserted through the skin into a large vein that feeds into a larger vein sitting above the heart. This means that the tip of the catheter sits close to the heart.

There are many veins that are suitable for inserting a central line. It can be inserted above or below the collarbone, on the side of the neck, in the groin or at the front of the elbow.

These types of catheters can stay in place for weeks to months, so long as they keep working and are not infected. A specialised catheter used for dialysis may be called a ‘vascath’.

Why is a central line used?

Central lines are used to give fluids, blood products, chemotherapy (cancer medicines) and other medicines (such as antibiotics) directly into the bloodstream. Many of these medicines and fluids are not suitable to be given through smaller veins in the hand and forearm because they are very irritating to the lining of the veins, and could cause small veins to form blood clots and stop working.

Central lines can also be used for taking blood samples and dialysis.

How is it put in?

A central line is inserted during a sterile (hygienic) procedure by a trained clinician or a supervised clinician in training. The person is laid flat during the procedure. Local anaesthetic is used to reduce pain and discomfort. After the clinician has inserted the catheter, it is held in place, usually by a couple of stitches or a specific device.

Before a central line can be used, a chest x-ray is done to make sure the line is in the right position.

What are the risks?

The risks include:

• infection – this can happen with any line, central or otherwise. The risk increases with the length of time the line has been in place. The signs of infection include redness, swelling and tenderness around the line as it enters the skin, and fever or chills. Usually, if a line becomes infected, it has to be removed.
• accidental puncture of the lung – this happens if the tip of the line is not in the right position. It causes air to leak into the chest, which will need to be drained off. It may also cause bleeding. This is why the person’s blood count and blood clotting are tested before the line is put in.

Keeping the line clean

Preventing infection is important. For this reason, touching a central line is discouraged. Anyone who needs to handle it must wash their hands first. The skin area where the line is inserted must be kept clean and dry. A transparent (see-through) dressing is generally used over the skin area where the line is inserted. This dressing is changed often (once a week or as needed).

When will the central line be removed?

Once the person’s doctor has decided the line is no longer needed, they will take it out. The person having the central line out will lie so air can’t enter the blood vessels.

Once the dressings and sutures are removed, the nurse will ask the person to take a breath in and hold it in while the line is removed. Once removed, the person can then resume normal breathing. Pressure will be applied to the area to prevent bleeding. A transparent dressing is then applied. This dressing can be removed in a couple of days.