Nursing Care of Arterial Lines
Welcome to this video tutorial on the nursing care of arterial lines!
What is an arterial line? Also known as an art-line or a-line, an arterial line is a thin catheter that is inserted into an artery. It is most commonly used to monitor blood pressure directly and accurately, as with close and accurate titration of blood pressure medications. It is also used to obtain samples for arterial blood gas analysis (ABG’s), and is convenient when frequent blood samples are needed, so the patient does not have to be stuck multiple times.
Common insertion sites include radial, brachial, and femoral arteries.
The radial artery is the most common site and its advantages include easy access, accurate readings, easy bleeding control, collateral circulation, and fairly easy mobility for the patient. The disadvantages of the radial artery are the small diameter, making it difficult to insert, and possible nerve damage or thrombosis.
The advantages of the brachial artery are the large diameter, making it easier to insert, and fairly easy bleeding control. The disadvantages include immobilization of the limb, thrombosis, and limited collateral circulation. The advantages of the femoral artery include large diameter, making it easy to insert, even when the patient has low volumes. The disadvantages include difficulty visualizing, hard-to-control bleeding, immobilization of the limb, and prone to infection, due to the location. The dorsalis pedis is a riskier site that is not used very often.
Before inserting an arterial line in the radial artery, the modified Allen’s test is done to determine collateral circulation of the radial and ulnar artery. Have the patient elevate their hand and clench their fist for about 30 seconds. Apply pressure to the radial and ulnar arteries in the wrist to stop the blood flow to the hand. Still elevated, the hand is opened and should appear blanched. Release ulnar pressure while maintaining radial pressure to check if there is adequate blood flow back to the hand. If the hand quickly becomes warm and returns to its normal color, this is a positive Allen’s test, meaning that one artery alone will be enough to supply blood to the hand and fingers, therefore the radial artery can be used for the arterial line. If the hand remains pale and cold, it is a negative test, and an arterial line should not be placed in this location.
When monitoring a patient with an arterial line, the monitor will show waveforms in red. The systolic phase is when the heart contracts, the dicrotic notch reflects the closure of the aortic valve, and the diastolic phase is the pressure going down in diastole.
Waveforms can be overdamped or underdamped. The overdamped waveform may be caused by compliant tubing, loose connections, a blood clot at the cannula tip, or a cannula that is kinked or up against an arterial wall. The underdamped waveform can be caused by long stiff tubing, too many stopcocks, or a defective transducer.
Along with understanding waveforms on the monitor, the nurse is responsible for zeroing (calibrating) the arterial line. Zeroing the system tells the transducer to “ignore” the pressure from the atmosphere.
First, ensure the transducer pressure tubing and flush solution are assembled correctly and free of air bubbles. Place the transducer at the level of the right atrium (called the phlebostatic axis).
Turn the stopcock off to the patient, remove the cap – this opens to air (atmosphere). Press ‘zero’ to set the atmospheric pressure to a zero reference point. Replace the cap and turn the stopcock back to neutral (off to the atmosphere). Remember, whenever the patient position is altered, the transducer height should be altered to keep it at the level of the right atrium.
Zeroing the line should be done at each shift change, every 4 hours, after each time blood is taken from the art-line system, and as needed.
To continue your assessment, check for blood pressure accuracy. Do this by comparing the arterial line pressure reading with the NIBP reading to be sure they fall under similar parameters. Discrepancies of 20 mmHg or more are considered to be inaccurate. If the art-line system was to fail, the non-invasive reading can be used as a backup.
Another portion of caring for an arterial line is the neurovascular assessment that includes the 5 Ps:
Pain – check for pain in the extremity of the arterial line.Pulses – check for collateral pulses and cap refill.Pallor – check the hand for a nice pink color, don’t want to see paleness or cyanosis.Paresthesia – sensation (no numbness or tingling).
Paralysis – movement of the extremity.
Check your hospital policy regarding who can insert art-lines. In most cases, the RN will be assisting the doctor or respiratory therapist with the insertion of an arterial line, and the following equipment is needed:
500 cc normal saline bag (with air removed)
Transparent dressing and tape
Cable to connect transducer to monitor
The saline bag should be changed daily and the tubing system every 72 hours or according to your hospital guidelines.
When drawing blood from an arterial line, always waste the first 10 mL—this blood is hemodiluted and will not give accurate results. Use a shielded blunt cannula, turn the stopcock off to the saline bag, so it is open between the patient and the port you’re drawing from. Draw blood tubes without additives first, then tubes with additives, anticoagulation profiles, and ABG’s. Remember to zero the system after use and flush with saline to clear the tubing of blood.
Indications for removal of arterial line:
- Arterial pressure monitoring no longer needed
- Frequent blood sampling no longer necessary
- Neurovascular compromise
- Bleeding at the site
- Infection and sepsis
- Arterial line system failure (such as a kinked catheter or thrombus at the tip).
When removing the arterial line:
- Verify your MD order to remove the art-line.
- Check the coagulation studies (PT and PTT) prior to removing the art-line.
- Keep the tip sterile, in case a culture is needed.
- Apply direct pressure to the site for at least 15 minutes, then apply a pressure dressing to the site – checking for bleeding, hematoma, or bruising.
- Continue to assess the 5 Ps – pain, pulses, pallor, paresthesia (sensation), paralysis (movement)
Thank you for watching this video tutorial on the nursing care of arterial lines!
Frequently Asked Questions
What is an arterial line?
Also known as an “art-line” or “a-line,” an arterial line is a thin catheter inserted into an artery for the purpose of continuous and accurate blood pressure monitoring (in the context of patients who are critical and/or receiving closely monitored and titrated vasopressors) and/or for the convenience of frequent arterial blood samples (arterial blood gases or ABGs) to minimize the amounts of sticks a patient receives.
What are the preferred locations for an arterial line?
The most common and recommended site for insertion is the radial artery due to its easy access, collateral circulation provided by the ulnar artery, ease of bleeding control, and allowance of patient mobility. Other site considerations include the brachial artery and the femoral artery. The brachial artery is larger in diameter, but requires more immobilization, has less collateral circulation, and has a higher risk of thrombosis. The femoral artery has the highest risk of infection, requires strict immobilization, is more difficult to visualize/monitor, and is a difficult location to control bleeding.
Where should the transducer of an arterial line be located?
The transducer of the a-line should be located at the same height as the right atrium. The phlebostatic axis is used to estimate this location. The phlebostatic axis is located at the 4th intercostal space on the middle axillary line. Each time a patient is moved, the location of the transducer should be reassessed.
What is the nurse’s responsibility for an arterial line?
The nurse is responsible for assessing the arterial waveform and addressing inaccuracies that can be identified by comparing the a-line blood pressure reading to a manual blood pressure reading. The nurse is responsible for zeroing the a-line every 4 hours, at change of shift, and after blood draws, in addition to any time an inaccuracy is suspected. The nurse must also continuously assess the site for signs of bleeding, dislodgement, hematoma formation, and infection, and must assess the patient for the 5 P’s: pain, pallor, pulses, paresthesia, and paralysis.
How do you flush an arterial line?
To flush an arterial line, first ensure that the stop cock is in neutral position to allow flow from saline into the catheter. Next, simply pull on the in-line flushing mechanism that is attached to the pressure tubing of the arterial line. Flush until there is no more blood visible in the chamber (in the case of flushing after a blood draw).
How do you zero an arterial line?
When zeroing the arterial line, first ensure that the transducer is at the level of the phlebostatic axis. Next, turn the stopcock off to the patient, and remove the cap—this opens the system to air (atmosphere). Press ‘zero’ on the monitor to set the atmospheric pressure to a zero reference point. Replace the cap and turn the stopcock back to neutral (off to the atmosphere). Flush the line after zeroing. Zeroing the arterial line should be done every 4 hours to ensure that the reading is accurate.
Why is Allen’s test performed before inserting an arterial line into the radial artery?
Prior to insertion of an a-line into the radial artery, the Allen’s test is performed to confirm adequate collateral circulation to the hand provided by the ulnar artery. This involves applying pressure to both the radial and ulnar arteries, observing the hand blanch, then removing pressure from the ulnar artery to confirm that the ulnar artery alone can perfuse the hand, demonstrated by the hand becoming pink. If the perfusion is inadequate, the radial artery is contraindicated for a-line insertion.
How do you remove an arterial line?
To remove an arterial line, first confirm the order by the physician, as this must be ordered prior to implementation. Next, review labs, specifically the PTT and PT, to ensure there are no increased risks for excessive bleeding. Next, slowly remove the catheter and immediately apply pressure with sterile gauze for 15 minutes. After removing the gauze, assess the site for any bleeding, hematoma formation, or bruising, and assess the patient for the 5 P’s.