Metabolic Alkalosis and Respiratory Alkalosis

Occurs in:

  • Diuretic therapy (low potassium) and pneumonia
  • Vomiting (H+ loss) and congestive cardiac failure (hyperventilation)

ABG hallmark:  the pCO2 will be reduced and the HCO3 raised

For example, in a patient who has been vomiting profusely and is, as a result, highly anxious with raised respiratory rate:

  • pH   7.53
  • pCO2   2.7 kPa
  • pO2   10.9 kPa
  • bicarbonate  34 mmol/L

The clinical picture needs to be considered – this patient is alkalotic with a low CO2, indicating a respiratory component, but the bicarbonate is high, rather than normal or low.