pH 7.24, PaO2 55 mm Hg, PaCO250 mm Hg, HCO3-30 mEq/L consistent with:

pH < 7.35 is acidosis ; pH >7.45 is alkalosisPrimary change in HCO3- is termed as metabolic (normal range: 22-30 meq/l)If there is acidosis and HCO3- decreased, the problem is a metabolic oneIf in acidosis HCO3- is increased or normal, the problem is compensatory metabolicPrimary change in CO2 is termed as respiratory (normal range: 35-45 mmHg)If in acidosis CO2 is raised, the problem is respiratoryIf in acidosis CO2 is decreased or normal, the problem is compensatory respiratorypH is low, HCO3- is high, Pa CO2 is high.Ref: Harrison's 18/e p363, 17/e p384, 2061