ABG ANALYSIS

Question 1

5 steps of interpretation…

Answer 1

The Resuscitation Council (UK) advocate a 5 step approach to arterial blood gas interpretation.

1. How is the patient?
2. Is the patient hypoxaemic?
   * the Pa0₂ on air should be >10 kPa
3. Is the patient acidaemic (pH <7.35) or alkalaemic (pH >7.45)
4. Respiratory component: What has happened to the PaCO₂?

• PaCO₂ > 6.0 kPa suggests a respiratory acidosis (or respiratory compensation for a metabolic alkalosis)
• PaCO₂ < 4.7 kPa suggests a respiratory alkalosis (or respiratory compensation for a metabolic acidosis)

5. Metabolic component: What is the bicarbonate level/base excess?

• bicarbonate < 22 mmol/l (or a base excess < - 2mmol/l) suggests a metabolic acidosis (or renal compensation for a respiratory alkalosis)
• bicarbonate > 26 mmol/l (or a base excess > + 2mmol/l) suggests a metabolic alkalosis (or renal compensation for a respiratory acidosis)

Question 2

ROME ACRONYM

Answer 2

ROME

Respiratory = Opposite

• low pH + high PaCO₂ i.e. acidosis, or
• high pH + low PaCO₂ i.e. alkalosis

Metabolic = Equal

• low pH + low bicarbonate i.e. acidosis, or
• high pH + high bicarbonate i.e. akalosis