Arterial Line Placement and Waveform Analysis

Clinical Applications

​Putting in an arterial line should be reserved for the right, clear clinical indications. Indications are:

• Continuous blood pressure monitoring in critically ill patients

• Management of patients with multiple vasoactive medications

• Long procedures needing beat-to-beat monitoring

• Frequent demand for blood samples

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But not all patients require an arterial line. The difference lies in knowing when to utilize the device as well as, arguably equally as important, when other modalities would be more suitable.

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Important Things to Keep in Mind: Before You Start

​Take a minute to glance over your contraindications. Although certain situations categorically exclude arterial line placement, others need clinical discretion.

Absolute Contraindications:

• Active infection of the site of planned placement

• Lack of pulses at site of intended placement

• Complete vascular occlusion

• Coagulopathy or peripheral vascular disease should not absolutely rule out arterial line placement, but should necessitate thorough risk-benefit assessment and perhaps extra precautions.

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Equipment Preparation

Arterial line placement success starts with proper preparation. This is what you will need:

Equipment Needed:

• Arterial line kit (20G catheter adult standard)

• Sterile drapes and personal protective gear

• Pressure transducer system

• Ultrasound equipment with sterile drape (stronger recommendation)

Having all of the equipment out in front of you when you start helps save time and minimizes contamination. Plan out your procedure and have all of the gear you'll need right there.

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The Procedure: A Systematic Approach

Patient position is what will destroy or save your success with arterial line insertion. For radial arterial access, optimal wrist extension over a roll towel with arm 45 degrees abducted maximizes your success.

Key Steps:

• Position patient and prepare equipment

• Strict hand hygiene and sterile attire

• Prepare your sterile field

• Utilize ultrasound to locate vessel (optimal)

• Local anesthetic infiltration if patient is awake

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The actual insertion is smooth and should be performed with finesse. Using the Seldinger technique, keep these pearls in mind:

• Shallow angle (30-45 degrees) maintained

• Wire advanced slowly without force

• Catheter threaded slowly over wire

• Good arterial waveform checked before securing

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Understanding Waveform Analysis

The arterial waveform is a complex tale of your patient's cardiovascular status. The normal waveform contains a number of important components:

Basic Components:

• Abrupt upstroke (ventricular ejection described)

• Systolic peak

• Dicrotic notch (closure of aortic valve)

• Diastolic runoff

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Practice reading these waveforms is necessary, but is worth it in terms of clinical information. Note both the look and the numbers - both contribute to the story.

 

Troubleshooting Common Problems

Even seasoned practitioners have issues. Here's what to do with issues that are common:

Dampened Waveform?

Begin with the fundamentals:

• Tubing kinks

• Air

• Transducer level and zeroing

• Catheter position

If you are having poor flow on insertion, attempt to slowly retract the catheter 1-2mm - sometimes the tip is stuck against the vessel wall.

 

Pro Tips for Success

After years of doing arterial line insertion, some tips:

• Use ultrasound guidance whenever possible - it makes first-pass success much better

• As a last resort for difficult cases, use a "liquid stylet" technique

• Watch out for these signs of impending complications:

• Recurrent blanching of digits

• Harsh pain on insertion

• Resistance to wire movement

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Your line maintenance

As soon as your line is secured, upkeep becomes important. The following daily monitoring should be conducted:

• Check insertion site

• Monitor waveform quality

• Verify system integrity

• Keep sterile

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Remember: an ideal functioning arterial line will function perfectly well for many days, yet one that's left unattended becomes a source of complications.