ABG

Question 1

Acidosis vs Alkalosis

Answer 1

PH: <7.35 // >7.45
CO2: High // low
HCO3: Low // High

Question 2

CO2 High/HCO3 low cause?

Answer 2

CO2 - resp acidosis
HCO3 - metabolic acidosis

Question 3

CO2 low// HCO3 high

Answer 3

CO2 - Respiratory alkalosis
HCO3 - metabolic alkalosis

Question 4

Normal ABG values

Answer 4

PH: 7.35-45
PO2: 10-14 KPa
PCO2: 4.5-6.0 KPa
HCO3: 22-26 mEq/l
Base excess:-2 to +2

Question 5

Acid base conditions in relation to PH/PaCO2?

Answer 5

Resp acidosis: Low PH High CO2
Resp alkalosis: high PH low CO2
metabolic acidosis: low pH normal PaCO2
Metabolic alkalosis: high pH normal PaCO2

Question 6

What does ABG show?

Answer 6

oxygenation, ventilation, and acid/base balance

Question 7

Arteries used in ABG?

Answer 7

Radial artery used commonly but femoral artery can be used if the patient is haemodynamically compromised.

Question 8

Contraindications for ABG

Answer 8

Arterial-venous (AV) fistula in the upper limb

Previous surgery involving the axilla eg previous axillary clearance during breast surgery

Peripheral vascular disease

Local infection at site

Broken skin at proposed site
​​​​​​​
Previous recent sampling from the site

Question 9

Purpose of Allen Test

Answer 9

to check that the patient’s hand is being adequately perfused by both the radial and the ulnar artery

Answer 10

1. Fist
2. Use fingertips, press against the wrist to occlude the blood flow to the radial and ulnar arteries.
3. Release fist and observe the blanched appearance to the hand, while maintaining pressure on both arteries.
4. Remove pressure from the ulnar artery whilst maintaining pressure on the radial artery, observe the patient’s hand flush with colour. This should occur within 5 to 8 seconds.
5. Repeat the process with the radial artery.

Question 11

How long should patient hold cotton swab?

Answer 11

5 minutes

Question 12

Why roll syringe?

Answer 12

To mix blood with heparin

Question 13

What should you do once you’re done?

Answer 13

Taking the sample straight to the laboratory / analyser or putting the sample in ice if there is any delay in analysing the sample.

also take patients details/forms

Question 14

performance of ABG

Answer 14

Handwash
PPE
Allen test
equipment
palpate
clean
prepare equip
inform patient - scratch
collect blood 90 degrees
pressure to site for 5 min
dispose of needle
evacuate air
apply cap
invert