Arterial Puncture and Line Placement

E. J. Mayeaux, Jr, MD, DABFP, FAAFP and Clint N. Wilson, MD

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Subject: Arterial Puncture and Line Placement

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Arterial puncture is a commonly employed procedure to obtain arterial blood for analysis. For most single-time samples in emergent and urgent situations, the single arterial puncture (stick) is adequate. Intra-arterial line placement is often used in situations that require access for frequent blood sampling and for real-time blood pressure monitoring. 
Arterial puncture is usually done using the radial artery and is performed by physicians and physician extenders, respiratory therapists, and other trained personnel. Arterial blood samples can be used for blood gas analysis, including measurement of the partial pressures of oxygen (PaO2) and carbon dioxide (PaCO2) and the pH of arterial blood. These values help the physician assess pulmonary function, establish diagnoses, direct further interventions, and determine the required intensity of monitoring in critically ill patients. 
Intra-arterial lines (arterial line, art-line, or a-line) are used as an invasive blood pressure monitoring method and for continuous access to blood vessels for frequent blood sampling. Blood pressure must be monitored closely when the patient is in shock, during a hypertensive emergency, and during vasopressor use. No data exist to support a specific site, but arterial lines are most commonly placed in the radial, brachial, or femoral arteries (a radial insertion is illustrated). A guidewire may be used during placement of an arterial line, or a direct puncture approach may be taken. 
Prior to radial artery puncture or arterial line insertion, an Allen test should be performed to assess collateral blood flow of the hand. To perform the Allen test, wrap your fingers around the patient’s wrist and compress both the ulnar and radial arteries. As you are doing this, have the patient elevate and then open and close his or her hand several times to allow blood to drain from the hand. Afterward, open the patient’s hand and see that it has blanched white. Release pressure from the ulnar artery, keeping the radial artery occluded. Within 2 to 3 seconds, normal skin color should return to first the ulnar side of the palm and then the entire palm shortly thereafter. If the hand remains white, collateral circulation is inadequate and radial artery puncture or arterial line is contraindicated. 


  • Arterial line kit

  • Arterial line monitoring equipment (as needed)

  • Pulse Doppler (as needed)

See Appendix E for skin cleansing recommendations and Appendix F for local anesthetic recommendations. 


  • Close monitoring of blood pressure (e.g., intensive care unit setting)

  • Access to arterial blood (frequent arterial blood gasses)

  • Frequent blood draws for laboratory tests

  • Continuous monitoring of oxygen saturation

Contraindications (Relative)

  • Dermatitis or cellulitis at insertion site

  • Absence of palpable pulse at chosen arterial site

  • Severe coagulopathy or platelet count <50,000

  • Uncooperative patient

  • Poor collateral circulation at proposed site (absolute contraindication)

The Procedure

Step 1

Obtain informed consent from the patient or proxy (see Appendix A). Perform the Allen test to assess adequate collateral arterial flow. Flush the arterial line tubing with normal saline to reduce risk of an air embolus. Check the kit to make sure all of the necessary components are present. Place the patient’s hand in anatomical position (palm up) and secure the wrist at a gentle extension (approximately 30 to 45 degrees). 

Step 2

Prep the skin over the proposed puncture site. Arterial line kits usually will come with skin cleaning supplies, but a separate chlorhexidine swab can be used instead (see Appendix E). 

Step 3

Drape the area per proper aseptic technique. Again, arterial line kits will usually provide a paper drape, but some practitioners prefer to use sterile towels or cloths. 

Step 4

Anesthetize the skin over the site with 3 to 5 mL of 1% to 2% lidocaine. (Be aware that excess fluid can diminish the pulse strength and/or distort anatomy.) 

Step 5

With the nondominant hand, gently palpate the artery. With the dominant hand, hold the intravascular catheter (an outer guidewire over a needle) with the needle bevel up and at a 30- to 45-degree angle. 

Step 6

Puncture the skin and advance the needle slowly at the site of arterial pulsation. 
  • PEARL: At this point, some physicians like to make a superficial nick in the skin at the site of insertion to ease the passage of the intravascular catheter, but this is not necessary.

Step 7

Advance until a flash of blood appears in the syringe. Once this flash is obtained, slowly advance the outer catheter into the artery, simultaneously removing the needle. If the arterial puncture was for a one-time arterial blood draw, the needle and catheter would be removed at this point, with a dressing placed on the site after appropriate pressure is held at the site for approximately 5 minutes. 
  • PEARL: The arterial line kit will come with a guidewire that can be used to assist in placement, especially in arterial lines not placed in the radial artery.

Step 8

Upon removing the needle, pulsatile blood return should be observed. At this point, connect the arterial line transducer tubing to the tip of the catheter. After ensuring the line is in a good place and a good waveform is seen on the arterial line monitors, secure your line to the skin with the suture provided. Once it is secure, place an occlusive dressing at the site. 


  • Local infection, pain, and bleeding

  • Blood clotting in the catheter

  • Nerve injury

  • Ischemic changes to the hand and wrist

Pediatric Considerations

In the pediatric population, the ulnar artery may be used as a primary site as long as the Allen test for good radial collateral circulation is checked first. The patient’s ability to cooperate also should be considered before deciding to attempt any procedure. 

Postprocedure Instructions

Arterial line catheters are not changed on a routine basis; rather, the site is monitored closely for signs of infection and changed based on clinical judgment. However, all arterial lines placed in emergent situations should be replaced. The dressing should be kept clean, dry, and intact and be changed as necessary. 

Coding Information and Supply Sources

Supplies may be purchased from these companies: 
  • Arrow Medical Products Ltd., 2400 Bernville Road, Reading, PA 19605. Phone: 1-800-233-3187. Web site:

  • Baxter, 1 Baxter Pkwy., Deerfield, IL, 60015-4625. Phone: 847-948-2000. Fax: 847 948-3642. Web site:

  • American Hospital Supply. Phone: 407-475-1168. Web site:

  • Cardinal Health, Inc., 7000 Cardinal Place, Dublin, OH 43017. Phone: 800-234-8701. Web site:

  • Owens and Minor, 4800 Cox Road, Glen Allen, VA 23060-6292. Phone: 804-747-9794. Fax: 804-270-7281.


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2008 MAG Mutual Healthcare Solutions, Inc.’sPhysicians’ Fee and Coding Guide. Duluth, Georgia. MAG Mutual Healthcare Solutions, Inc.2007.