A critically ill patient has the following arterial blood gas. What acid-base disturbance is occurring? pH = 7.27 PCO2 = 54 mmHg (normal range: 35 - 45 mmHg) pO2 = 78 mmHg (normal range: 80 - 100 mmHg) HCO3 = 27 mEq/L (normal range: 22 - 26 mEg/L) a-Metabolic acidosis b-Metabolic alkalosis c-Respiratory alkalosis d-Respiratory acidosis e-There is no acid-base disorder