How do you insert a femoral arterial line?

Femoral Arterial Line Insertion Technique

Ultrasound-guided technique should be used for femoral arterial line placement to improve success rates and reduce complications. 1

Patient Preparation and Equipment

• Position patient supine with slight external rotation of the hip
• Prepare sterile field covering the femoral area
• Equipment needed:
  • Ultrasound machine with high-frequency linear probe and sterile cover
  • Arterial catheter kit (typically 20G for adults)
  • 1% lidocaine for local anesthesia
  • Sterile drapes, gloves, mask, and cap
  • Chlorhexidine-alcohol solution for skin preparation

Step-by-Step Procedure

1. Pre-procedural Assessment

• Evaluate collateral circulation if possible
• Review CT angiography if available to assess for atherosclerosis, vessel diameter, and calcification 2
• Confirm no contraindications (severe peripheral vascular disease, coagulopathy, local infection)

2. Skin Preparation

• Apply alcoholic chlorhexidine solution (>2%) to insertion site 1
• Allow antiseptic to dry completely before proceeding
• Use maximum sterile barrier precautions (mask, cap, sterile gown, and gloves) 1

3. Ultrasound Vessel Identification

• Place ultrasound probe over the femoral triangle below the inguinal ligament
• Identify the femoral artery lateral to the femoral vein
• Optimal puncture site is at the common femoral artery (CFA) overlying the femoral head 3
• The femoral head can be used as a reliable landmark as the CFA overlies it in 92% of cases 3

4. Local Anesthesia

• Infiltrate 1-2 mL of 1% lidocaine at the planned insertion site
• Avoid intravascular injection

5. Arterial Puncture Technique

• Hold ultrasound probe in non-dominant hand
• Use real-time ultrasound guidance with either:
  • Short-axis (out-of-plane) approach: Visualize artery in cross-section
  • Long-axis (in-plane) approach: Visualize artery longitudinally with needle path
• Insert needle at 30-45° angle under direct ultrasound visualization
• Confirm arterial entry by pulsatile blood return
• Once blood return is obtained, lower the angle of the needle to approximately 15°

6. Catheter Insertion

• After blood return, advance guidewire through needle (Seldinger technique)
• Remove needle while holding guidewire in place
• Thread catheter over guidewire
• Remove guidewire while holding catheter in place
• Connect to pressure transducer system
• Secure catheter with suture and apply sterile dressing

7. Confirmation and Documentation

• Confirm arterial waveform on monitor
• Document procedure including site, catheter size, and any complications

Evidence-Based Benefits of Ultrasound Guidance

Ultrasound guidance for femoral arterial line placement offers several advantages:

• Higher first-attempt success rates (92.9% vs 55.3% with landmark technique) 4
• Reduced procedure time (45.1 seconds vs 79.4 seconds) 4
• Lower risk of complications, particularly inadvertent femoral vein puncture 1
• Better visualization of anatomical variations and vessel pathology 5

Monitoring for Complications

• Watch for signs of limb ischemia (pallor, decreased pulses, pain)
• Consider near-infrared oximetry to compare perfusion between cannulated and non-cannulated limbs 2
• If significant difference in perfusion is detected, consider placement of a small cannula in the distal superficial femoral artery 1
• Monitor for hematoma formation, pseudoaneurysm, or infection

Special Considerations

• In patients with difficult access (obesity, hypotension, edema), ultrasound becomes even more critical 5
• For patients requiring long-term monitoring, femoral arterial lines have lower failure rates compared to radial lines (5.4% vs 25.6%) 6
• In pediatric patients, ultrasound guidance is strongly recommended as it improves first-pass success and reduces complications 1
• When femoral access is required for large sheaths, consider the AGU technique (Angiographic-Guidewire-Ultrasound) for optimal placement 7

Remember that while femoral arterial lines may have lower failure rates than radial lines, site selection should consider the specific clinical scenario and patient factors. Ultrasound guidance significantly improves outcomes regardless of chosen site.