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Learning About an Arterial Line

What is an arterial line?

An arterial line is a thin, flexible tube that is placed into an artery. It helps your doctors and nurses check your blood pressure and take blood samples.

It is used in operating rooms and intensive care units (ICUs). You may hear it called an "art-line" or "A-line."

This line is usually placed in the wrist or groin.

Why is an arterial line used?

An arterial line is used to:

  • Get a constant blood pressure reading. An arterial line is more accurate than a blood pressure cuff. The line constantly sends your blood pressure reading to a monitor. That means your medical team can see it easily.
  • Take blood samples to measure the oxygen and carbon dioxide in your blood. Knowing the levels of these gases helps your medical team prevent or treat circulation or lung problems.

How is an arterial line inserted?

  • A needle is used to put the arterial line in. First, the area where the needle will go in is cleaned.
  • An ultrasound may be used to help guide the needle into the artery.
  • When the arterial line is in, it may be held in place with a stitch. You will see a bandage taped to your skin to help hold the line in place.
  • Your wrist will be taped to a soft board to keep you from bending it.

Having a needle put into an artery is more painful than having it put into a vein. That's because the arteries are deeper and are near nerves. If you are awake at the time, your medical team will use medicine to numb the area first. Any mild discomfort usually gets better after the line is in place.

There are a few risks to having an arterial line put in. These risks include infections, bleeding, damage to the artery, and blood clots. ICU teams check the line regularly to help prevent these problems.

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor or nurse advice line (811 in most provinces and territories) if you are having problems. It's also a good idea to know your test results and keep a list of the medicines you take.

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