Blood Gas INTERPRETATION

Clinical Picture

• 40-year-old male presenting with vomiting
• Patient is alert and responds appropriately; generally unwell
• Known history of alcohol use disorder
• Tachycardic and hypotensive

Findings

• Sample type: Arterial
• pH: 7.49
• PaCO2: 44
• HCO3: 32
• Base excess: 8
• PaO2: 90
• Sats: 96
• Acid-base balance: Abnormal
• Other parameters: Hyponatremia and hypokalemia

Summary 

• pH, HCO3, and base excess are not within normal limits on this blood gas (alkalotic). Sodium and potassium are not within normal limits.
• The alkalotic bicarbonate (HCO3) and base excess match with the alkalotic pH, consistent with a metabolic alkalosis. The normal PaCO2 indicates compensation has not yet occurred; therefore, this is an uncompensated metabolic alkalosis, such as that commonly found in persistent vomiting.

Further reading

• Arterial Blood gas (ABG) interpretation guide