What is an arterial line insertion?

An arterial line insertion is a procedure in which your doctor or a specially trained nurse inserts a tiny tube (catheter) in an artery, usually in the wrist. An arterial line is used in very ill or injured patients to take continuous blood pressure readings. This is called intra-arterial pressure (IAP) monitoring. It also provides a way to draw blood for lab tests without repeated punctures.           

Continuous IAP readings are more accurate than those taken by a blood pressure cuff. IAP readings also provide more information about your health status than a cuff.  

Arterial line insertion and IAP is only one way to monitor your blood pressure and condition. Your care team will evaluate your IAP readings along with other vital signs, physical exam, medical history, and diagnostic tests. Ask your doctor about all the methods used to evaluate your condition.  

Why is an arterial line insertion performed? 

Your doctor may recommend an arterial line to measure blood pressure continuously. It is especially useful in patients who are critically ill or injured or whose blood pressure is unstable. 

An arterial line also provides a way to take frequent blood samples for lab tests. This avoids repeated needle punctures to draw blood. Lab tests include arterial blood gas testing (ABG). An ABG helps evaluate your oxygen status and acid-base balance. By definition, blood for an ABG comes from an artery.

Your doctor may recommend an arterial line for the following conditions: 

  • Cardiovascular conditions including severe uncontrolled hypertension (high blood pressure), heart failure, and cardiopulmonary arrest  
  • Coma including coma due to stroke and head injury 
  • Drug overdose or poisoning including ingestion of drugs or exposure to toxins, such as organophosphates including nerve gas  
  • Low blood pressure (hypotension) including hypotension due to severe bleeding, sepsis, and shock
  • Major surgery including open-heart surgery, chest surgery, brain surgery, organ transplants, trauma surgery, and certain abdominal surgeries 
  • Medications that affect blood pressure including intravenous norepinephrine (Levophed), dopamine, and sodium nitroprusside (Nipride)
  • Respiratory failure including respiratory failure due to severe asthma or pulmonary edema

Who performs arterial line insertion?

The following doctors insert arterial lines:  

  • Cardiologists and cardiac surgeons specialize in diagnosis and treatment of conditions of the heart and its blood vessels. Cardiac surgeons are sometimes called cardiothoracic surgeons.
  • Critical care medicine doctors and critical care surgeons specialize in the diagnosis and management of critical and life threatening conditions.
  • Emergency medicine doctors and pediatric emergency medicine doctors specialize in rapidly diagnosing and treating acute or sudden illnesses and injuries, and complications of chronic diseases. 
  • Thoracic surgeons specialize in the surgical treatment of diseases of the chest, including the blood vessels, heart, lungs and esophagus. Thoracic surgeons may also be known as cardiothoracic surgeons.

Other specialists who may insert arterial lines include:

  • Registered nurses (RNs) are licensed healthcare professionals who provide skilled patient care and coordinate their care. RNs must have additional training to insert arterial lines. 
  • Advanced practice nurses (APNs) are registered nurses with advanced specialty training in primary or acute care at the master's level or higher. 

How is an arterial line insertion performed?

Your arterial line insertion will be performed in an intensive care unit (ICU), surgical area, or emergency room setting. The procedure generally includes these steps:

  1. You are positioned comfortably so that your doctor or nurse can easily access the insertion area. This is usually the wrist, but may be the inside of the elbow, the groin, a foot, or an armpit.
  2. Your doctor or nurse cleans the arterial line insertion area with an antiseptic and numbs the area with a local anesthetic.
  3. Your doctor or nurse inserts a small tube (catheter) through the skin into the artery and usually sews it in place.     
  4. The catheter connects to tubing filled with salt water (saline) and a transducer device. The transducer turns a pressure signal from inside the artery into an electrical signal. The electrical signal appears as a continuous waveform and a blood pressure reading on a monitor screen. 
  5. Your doctor or nurse covers the arterial line insertion site with a sterile dressing to keep it clean.