7,440 MR RM: Blood Gas ABG interpretation

Mister Ronald McDonald (MR RM) is a helpful flowchart for interpreting acid-base disorders, specifically for determining whether a patient’s condition is due to a metabolic (M) or respiratory (R) cause:1. Check the pH (7.4 is the cutoff) • pH > 7.4 → Alkalosis • pH < 7.4 → Acidosis2. Assess Carbon Dioxide (CO₂) Levels (PaCO₂) • The key threshold is 40 mmHg: • If CO₂ > 40 mmHg, this suggests respiratory acidosis or metabolic alkalosis. • If CO₂ < 40 mmHg, this suggests respiratory alkalosis or metabolic acidosis.3. Determine the Cause • In Alkalosis: • If CO₂ > 40, the cause is Metabolic (M) Alkalosis. • If CO₂ < 40, the cause is Respiratory (R) Alkalosis. • In Acidosis: • If CO₂ > 40, the cause is Respiratory (R) Acidosis. • If CO₂ < 40, the cause is Metabolic (M) Acidosis.Key Takeaway • The chart helps determine whether a patient’s acid-base imbalance is due to a metabolic or respiratory cause by analyzing pH and CO₂ levels.