Certified Medical-Surgical Registered Nurse Practice Test 2024 - Free Practice Questions and Study Guide

Mannitol is a type of osmotic diuretic that is commonly used to decrease intracranial pressure in conditions such as a subdural hematoma. When a patient has a subdural hematoma and dilation of one pupil, it indicates increased intracranial pressure. Mannitol works by drawing fluid out of brain tissue and into the bloodstream, ultimately reducing the pressure inside the brain. This helps improve blood flow and oxygenation to the brain, potentially preventing further brain damage. Therefore, the correct answer is C, to decrease brain pressure through diuresis. Options A, B, and D are incorrect because mannitol is not primarily used to reduce eye pressure, prevent kidney damage, or increase blood pressure. Its main mechanism of action is to decrease intracranial pressure through diuresis.