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Clinical Skills

Arterial blood gas sampling

A structured guide to performing arterial blood gas sampling safely and effectively.

1. Introduction

Arterial blood gas sampling is used to assess oxygenation, ventilation and acid-base status. It is a more painful and higher risk procedure than venepuncture, so clear explanation and good technique are important.

2. Preparation

Confirm the indication, identify the patient, explain the procedure and gain consent. Check for contraindications and relative contraindications such as inadequate collateral circulation, local infection, severe peripheral vascular disease or a vascular graft at the intended site. Assemble the equipment, perform hand hygiene and wear appropriate personal protective equipment.

3. Procedure

Position the wrist in slight dorsiflexion if using the radial artery. Palpate the artery, clean the skin and allow it to dry. Insert the heparinised syringe needle at an appropriate angle until arterial blood fills the syringe. Remove the needle, apply firm pressure for adequate haemostasis and expel any air bubbles before capping the sample.

4. Aftercare

Label the sample promptly, note the inspired oxygen concentration and send the sample quickly for analysis. Reassess the puncture site for bleeding or haematoma and document the procedure and any complications.

Preparation

Procedure

Aftercare