Overview
Clinical Meaning
Arterial blood gas (ABG) analysis provides critical information about a patient's acid base balance, oxygenation, and ventilation status.
Arterial blood gas (ABG) analysis provides critical information about a patient's acid-base balance, oxygenation, and ventilation status. The normal ABG values — pH 7.35-7.45, PaCO2 4.7–6.0 kPa, PaO2 10.7–13.3 kPa, HCO3 22–26 mmol/L, and SaO2 95-100% — represent the body's tightly regulated homeostatic mechanisms. Respiratory acidosis (pH < 7.35, PaCO2 > 45) results from hypoventilation, while respiratory alkalosis (pH > 7.45, PaCO2 < 35) results from hyperventilation. Metabolic acidosis (pH < 7.35, HCO3 < 22) occurs from bicarbonate loss or acid accumulation, while metabolic alkalosis (pH > 7.45, HCO3 > 26) occurs from acid loss or bicarbonate excess. Compensation occurs when the opposing system attempts to normalize pH.
