Which arterial blood gas pattern indicates metabolic alkalosis?

Which arterial blood gas pattern indicates metabolic alkalosis?

• A. Low pH, low HCO3-, PaCO2 low
• B. High pH, high HCO3-, PaCO2 may be high or normal depending on compensation.
• C. Low pH, low HCO3-, PaCO2
• D. High pH, low HCO3-, PaCO2 low

Answer: (B)

Metabolic alkalosis shows an alkalemic pH with elevated bicarbonate (HCO3-). The body's compensation tries to restore balance by retaining carbon dioxide, so the PaCO2 tends to be higher than normal or, in early/less compensated cases, can be normal. Therefore an ABG pattern with high pH and high HCO3-, with PaCO2 that is high or normal depending on compensation, best indicates metabolic alkalosis.

Metabolic alkalosis shows an alkalemic pH with elevated bicarbonate (HCO3-). The body's compensation tries to restore balance by retaining carbon dioxide, so the PaCO2 tends to be higher than normal or, in early/less compensated cases, can be normal. Therefore an ABG pattern with high pH and high HCO3-, with PaCO2 that is high or normal depending on compensation, best indicates metabolic alkalosis.