Arterial blood gas (ABG) interpretation is something many medical& NURSING students find difficult to grasp (we’ve been there). We’ve created this guide, which aims to provide a structured approach to ABG interpretation whilst also increasing your understanding of each result’s relevance. The real value of an ABG comes from its ability to provide a near-immediate reflection of the physiology of your patient, allowing you to recognize and treat pathology more rapidly.

1. Mr. MAHESH. S (M.Sc.
NURSING )
NURSE EDUCATOR
MGMCRI

2. What is an ABG?
• An ABG is a blood test that measures the acidity, or pH, and
the levels of oxygen (O2) and carbon dioxide (CO2) from an
artery. The test is used to check the function of the patient’s
lungs and how well they are able to move oxygen and remove
carbon dioxide.

3. ABGS Are drawn for a variety of
reasons.
These may include concern for:
• Lung Failure
• Kidney Failure
• Shock
• Trauma
• Uncontrolled diabetes
• Asthma
• Chronic Obstructive
Pulmonary Disease
• Hemorrhage
• Drug Overdose
• Metabolic Disease
• Chemical Poisoning

4. SITES OF ARTERIAL BLOOD
SAMPLING

5. ABG INTERPRETATION
Step 1: Know the normal values
Step 2: Determine if pH is under acidosis or alkalosis
Step 3:Determine if acid-base is respiratory or metabolic
Step 4: Remember ROME
Step 5: Tic-Tac-Toe
Step 6: Mark the Chart
Step 7: Match it up
Step 8: Determine compensation

6. STEP 1: KNOW THE NORMAL VALUES

7. STEP 2: DETERMINE IF PH IS UNDER
ACIDOSIS OR ALKALOSIS
pH level below 7.35 is acidosis
pH level above 7.45 is alkalosis.

8. paCO2 = Respiratory
HCO3 = Metabolic

9. STEP 4: REMEMBER ROME

10. STEP 5: TIC-TAC-TOE

11. STEP 6: MARK THE CHART
7.26
18
32

12. STEP 7: MATCH IT UP

13. STEP 8: DETERMINE COMPENSATION
• If pH is NORMAL, PaCO2 and HCO3 are both
ABNORMAL - Compensated

14. PARTIALLY COMPENSATED
• If pH is ABNORMAL, PaCO2 and HCO3 are both
ABNORMAL

15. UNCOMPENSATED
• If pH is ABNORMAL, PaCO2 or HCO3 is
ABNORMAL
40
40