Specimen Name Result Units Range

ABG pH 7.54 (7.36-7.44)
PaO2 108 mmHg (70-100)
PaCO2 27 mmHg (35-45)
HCO3- 25 mmol/L (21-26)

No History

What is the acid-base disorder?


Respiratory Alkalosis - Acute
  • pH : alkalaemia
  • PCO2 : respiratory
  • HCO3- : should be 21-23 if acute
  • PO2 + 1.25*PCO2 ≈ 141 : normal A-a gradient if on room air

 

ABG Correction Factors

  1. Metabolic Acidosis:
    • PCO2 : last 2 digits of pH ≥ 7.10
    • HCO3- : for each 10 mmol/L fall → ↓ PCO212 mmHg
  2. Metabolic Alkalosis:
    • PCO2 : last 2 digits of pH ≤ 7.60
    • HCO3- : for each 10 mmol/L rise → ↑ PCO27 mmHg
    • *least well compensated due to hypoxaemia 2° hypoventilation
  3. Respiratory Acidosis:
    • Acute : for each 10 mmHg PCO2 rise → ↑ HCO3-1-2 mmol/L
    • Chronic : for each 10 mmHg PCO2 rise → ↑ HCO3-4 mmol/L
  4. Respiratory Alkalosis:
    • PCO2 : for each 10 mmHg fall → ↓ HCO3-2.5 mmol/L