This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'pH 7.24, PaO2 55 mm Hg, PaCO250 mm Hg, HCO3-30 mEq/L consistent with: \nSelect and explain. \nA. Respiratory acidosis, B. Respiratory alkalosis, C. Metabolic acidosis, D. Metabolic alkalosis', 'role': 'user'}, {'content': "Answer: A \nExplanation: 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", 'role': 'assistant'}]