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Arterial Blood Gases

The arterial blood gas is useful in acutely unwell patients for assessing acid-base balance and oxygen status. This section outlines the approach for collecting an ABG.

Clinical Use

Indications

Assessing respiratory & acid base status, testing of carboxy- and methaemoglobin
Contraindications

Coagulopathy, inadequate collateral circulation

Equipment & Preparation

Gloves
Alcohol swabs
1% Lignocaine

If appropriate
Blood Gas Syringe

Heparinised syringe with needle
Cap for Blood Gas Syringe
Dressing

Gauze and tape
Exit Strategy

Sharps container
Blood Tubes for Samples
Documentation

Test request form, patient labels

Identifying an Artery

How To Perform

Identify that this is the correct patient
Explain the procedure and ask for patient's consent
Positioning

Raise the bed to waist level
Wash hands and don gloves
Prepare the Site

Decontaminate with alcohol swab, allow to air dry
Inject 1% lignocaine if appropriate
Identify the Artery

Palpate for a pulse proximal to desired collection site
Prepare the patient for a ‘very sharp scratch'
Insert the Needle

Bevel up, ~45 degrees from skin, until flashback is seen
Collect Blood

Allow the syringe to self-fill
Remove the Needle

Apply gentle pressure to the area using gauze or cotton ball for at least five minutes
Prepare the Sample

Remove the needle, cap the syringe, gently invert
Clean Up

Dispose of sharps and other waste
Remove gloves and wash hands
Processing

Label the syringe and send to the lab

Complications

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