This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Medicine
[{'content': 'When evaluating an ABG from a client with a subdural hematoma, the nurse notes the PaCO2 is 30 mm Hg. Which of the following responses best describes this result? \nSelect and explain. \nA. Appropriate; lowering carbon dioxide (CO2) reduces intracranial pressure (ICP)., B. Emergent; the client is poorly oxygenated., C. Normal, D. Significant; the client has alveolar hypoventilation.', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A normal PaCO2\xa0value is 35 to 45 mm Hg. CO2\xa0has vasodilating properties; therefore, lowering PaCO2\xa0through hyperventilation will lower ICP caused by dilated cerebral vessels.\n\nOption B: Oxygenation is evaluated through PaO2\xa0and oxygen saturation.\nOption D: Alveolar hypoventilation would be reflected in an increased PaCO2.', 'role': 'assistant'}]