Indications

• Beat-to-beat blood pressure monitoring
• Frequent and/or Arterial blood gas sampling
• Hemodynamic instability
• Titration of vasoactive drugs

Absolute contraindications

• Absent pulse
• Raynaud’s syndrome
• Buerger’s disease
• Poor perfusion

Equipment

• Arterial Line
  • Long 20G cannula (24% failure)
  • Modified Seldinger guidewire cannula (17% failure)
  • Seldinger arterial line set (7% failure)

• Rolled towel and tape (arm positioning)
• Ultrasound + sterile probe cover and gel
• 25G needle + 5ml syringe (anaesthetic)
• Fluid giving set primed with saline 500ml or 1000ml of sterile 0.9% sodium chloride in pressure bag at 300mmHg
• Transducer set
• Arm board
• Non-injectable cap
• 3ml blood gas syringe
• Suture or Steri-Strips
• Transparent adhesive dressing

Procedure

• Prime the measure set as above
• Identify the radial artery by USS or by palpation
• Infiltrate local anesthetic over the area of intended insertion
• Insert and advance the needle until arterial flashback is observed
  • insertion under direct ultrasound guidance will enhance first pass success
• Advance a further 1-2mm to ensure needle lumen is entirely in the vessel
• Cannulate the vessel- this can be done directly, with an inbuilt guidewire, and/or by performing Selinger technique. Using a Selinger technique will enhance the likelihood of successful cannulation.
• Pulsatile flow of blood confirms position in vessel, to avoid excessive blood loss during transducer connection put pressure on artery proximal to insertion line when removing wire and connecting to transducer set.
• Connect transducer set
• Secure line (suture in position to reduce risk of dislodgement) and dress insertion site
• Arm board to hold wrist in extension
• Calibrate line
  • set off to patient and open to air then press ‘Zero’ on monitor
  • when ‘0’ on screen, set open to patient and transducer, off to air

How to take ABG sample

• Aspirate to clear saline from line
  • Remove cap from sampling port
  • Attach a 5ml syringe.
  • Turn three-way tap to open from the patient to the sampling port.
  • Aspirate 2-5ml
  • Turn three-way tap so the arterial line is closed from the patient to the sampling port
  • Remove the 5ml syringe and discard
• Take ABG
  • Attach blood gas syringe
  • Turn three-way tap to open from the patient to the sampling port.
  • Allow VBG syringe to fill
  • Turn three-way tap so the arterial line is closed from the patient to the sampling port
  • Remove the VBG syringe
• Flush
  • Turn the three-way tap so the arterial line is open from the patient to the flush device (closed to air)
  • Pull the toggle to flush the line
  • Turn the three-way tap so the arterial line is open from the flush device to the sampling port (closed to patient)
  • Flush again into sterile gauze swab to ensure all air is expelled from the system
• Reconnect to monitor
  • Turn the three-way tap so it is open to the patient and the transducer
  • Check there is an arterial waveform on the monitor
  • Place a new red non-injectable bung on the sampling port