6 Easy Steps to ABG Analysis
1.
2.
3.
4.
Is the pH normal? Label it
Is the CO2 normal? Label it
Is the HCO3 normal? Label it
Does the CO2 or the HCO3 go in the opposite direction? If yes, then there
is compensation
5. Are the pO2 and O2 saturation normal? If no, then they are hypoxic
Test
pH
pCO2
HCO3
pO2
O2 saturation
Normal
7.35-7.45
35-45 mmHg
22-26 Meq/L
80-100 mmHg
98-100%
↓Value
Acidosis
Alkalosis
Acidosis
Hypoxemia
Hypoxemia
↑Value
Alkalosis
Acidosis
Alkalosis
ROME
Respiratory Opposite (arrows are opposite)
Metabolic Equal (arrows are equal)
Ex:
 pH 7.50
 CO2 30
= respiratory alkalosis (breathing too fast, blowing co2 too fast, causing anxiety,
pain, fever, infection, hyperventilation)
Respiratory is quickest avenue for compensation
Pain, fever, infection will increase respiratory rate and increase chance to getting
respiratory alkalosis.
 pH 7.31 acidosis
 CO2 48
= respiratory acidosis (hypoventilation, atelectasis, trauma, narcotics) could be
respiratory arrest, pain, CNS depressants
 pH 7.20
- CO2 36
 HCO3 14
Metabolic acidosis (cardiac arrest patients), patients who have GI problems –
diarrhea = IBD
 pH 7.47
 CO3 45
 HCO3 33
Metabolic alkalosis (GI loss from vomiting or emesis, NG tube suction)