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?
A normal PaCO2 value is 35 to 45 mm Hg. CO2 has vasodilating properties; therefore, lowering PaCO2 through hyperventilation will lower ICP caused by dilated cerebral vessels.

Option B: Oxygenation is evaluated through PaO2 and oxygen saturation.
Option D: Alveolar hypoventilation would be reflected in an increased PaCO2.
Appropriate; lowering carbon dioxide (CO2) reduces intracranial pressure (ICP).
Emergent; the client is poorly oxygenated.
Normal
Significant; the client has alveolar hypoventilation.