Answer is C (Respiratory and metabolic acidosis) The acid base disorder is therefore both respiratory and metabolic acidosis. There is acidosis (pH < 7.35). Raised PCO2 (acidosis) indicates that change in CO2 is in keeping with change in pH. The respiratory component is therefore primary. Decreased HCO3 (acidosis) indicates that change in HCO3 is also primary. The acid base disorder is therefore both respiratory and metabolic acidosis.