Q. A 30-year-old woman comes to the emergency department with a severe headache and nausea. She has been experiencing these symptoms for the past week and they have been getting worse. She also reports seeing "flashing lights” and has difficulty with her vision. She has no history of headaches or any other significant medical conditions. A CT scan reveals increased pressure within the skull. She is diagnosed with intracranial hypertension. The patient is treated with mannitol to decrease the pressure within the skull. What is mannitol’s mechanism of action in treating intracranial hypertension?