Arterial blood gases
pH CO2 HCO3 Acid status
Metabolic acidosis (rare, without compensation)
Metabolic acidosis + compensatory respiratory alkalosis
Metabolic alkalosis
Metabolic alkalosis + compensatory respiratory acidosis
Respiratory acidosis
Respiratory acidosis + compensatory metabolic (renal) alkaosis
Respiratory alkalosis
Respiratory alkalosis + compensatory metabolic (renal) acidosis
  pCO2:   35 - 45 mmHg (4.6 - 6 kPa)
  HCO3:   22 - 26 mmol/l (< 22 is acid).
  Key:     ↓ Low     ✓ Normal     ↑ High