Arterial blood gas (ABG) sampling procedure

Introduction

• Wash hands
• Introduce self
• Patient’s name, DOB and wrist band
• Explain procedure and obtain consent
• Check for allergies (including chlorhexidine)
• Ask preferred (or non-dominant) arm 

Preparation 

• Wash hands 
• Clean tray
• Gather equipment around tray (think through what you need in order)

• Wash hands
• Open packets and place neatly in tray, keeping items in plastic parts of packets (without touching the instruments themselves)
• Put needle on syringe if not already attached
• Return to patient

Procedure

Modified Allen’s test

• Wash hands 
• Expose wrist and place a pillow beneath it
• Perform modified Allen’s test
  • With patient’s palm facing upwards, occlude both radial and ulnar arteries
  • Ask patient to open and close hand until the palm becomes pale, then ask them to hold it open
  • Release the ulnar artery and time how long the hand takes to reperfuse (i.e. become pink again)
  • If ≤10 seconds, continue with ABG

Preparation

• Firmly hyper-extend the patient’s wrist (ask them, or hold it down yourself)
• Palpate radial artery with index and middle fingers
• Wash hands
• Put on gloves
• Sterilise area using skin-cleansing wipe (clean for 30 seconds, then allow to air-dry for 30 seconds)
• Expel air from the heparinised syringe (only necessary for some ABG kits)

Sampling

• With the index and middle fingers of your non-dominant hand, re-palpate the artery just proximal to the point of insertion
• Holding the bevel of the needle as close to your non-dominant hand’s fingers as possible (without touching them), insert the needle (bevel up) into the site of pulsation, at 45˚ to the skin
• When blood enters the syringe, hold it still while it self-fills (no need to aspirate)
• Place gauze loosely over the puncture site while you remove the needle. Then apply pressure to the gauze once the needle is fully removed.
• Secure needle with rubber block or needle cover
• Maintain pressure over the gauze for 5 minutes. Check it has stopped bleeding before taping down the gauze.

To complete

• Thank patient and restore clothing
• Remove the needle from the syringe and dispose of it in the sharps bin
• Put the cap on the end of the syringe and expel the air
• Discard waste and clean tray; then discard gloves; wash hands
• Label the sample and take it to the blood gas machine or call the porters to collect it on ice
• Document procedure and results in patient’s notes with the patient’s FiO₂ and temperature

Try it out now!

1. Arterial blood gas
2. More procedure OSCE stations here