ABG

Question 1

Explain the timing of when an ABG can be taken

Answer 1

Ideally 15-20mins of cardiovascular stability should elapse following a change of oxygen therapy before ABG is taken

Taken immediately if an emergency situation

Question 2

Which arteries can be used for ABG sampling

Answer 2

Radial
Femoral
Brachial

Question 3

What test must you do if using the radial artery for an ABG?

Answer 3

Allen’s test

Positive modified Allen test – If the hand flushes within 5-15 seconds it indicates that the ulnar artery has good blood flow; this normal flushing of the hand is considered to be a positive test.

Negative modified Allen test – If the hand does not flush within 5-15 seconds, it indicates that ulnar circulation is inadequate or non-existent; in this situation, the radial artery supplying arterial blood to that hand should not be punctured. WHO (2010)

Question 4

Name some cautions and contraindications for ABG

Answer 4

Avoids any pre-existing lesions or infections at the puncture site

Presence of a surgical shunt (e.g. dialysis patients)

History of peripheral vascular disease

Patient on anticoagulation therapy (relative contraindication)

Inadequate collateral circulation confirmed by negative Allen’s test

Question 5

What equipment is required for an ABG?

Answer 5

blood gas syringe witf safety needle

gloves

gel

sterile gauze swabs

alcohol

chlorhexidine skin prep

occlusive dressing

• consider using local anaesthetic

Question 6

Talk through the procedure for obtaining an ABG

Answer 6

1. Check patient ID
2. Check patient for allergy
3. Collect equipment
4. Wash hands + put apron on
5. Palpate for pulses
6. Allens test if using radial artery
7. Clean area 30 secs cross hatch technique, allow to dry
8. Prep blood gas syringe
9. gel hands, put gloves on
10. re-palpate for pulse, above insertion site or either side of insertion site
11. Enter radial artery at 30-45 degree angle opposite to direction of blood flow
12. obtain 1-2mls blood
13. Remove needle, direct pressure for 5 mins
14. dispose of sharps
15. expel any air bubbles from syringe, apply cap
16. ensure bleeding has stopped
17. Label syringe at bedside, make note of oxygen % received by pt and pt temp at time of sample

take sample to machine immediately