Certified Medical-Surgical Registered Nurse Practice Exam

What is the primary purpose of administering mannitol to a patient with a subdural hematoma?

1. To reduce intraocular pressure

2. To prevent acute tubular necrosis

3. To promote osmotic diuresis to decrease ICP

4. To draw water into the vascular system to increase blood pressure

The correct answer is: To promote osmotic diuresis to decrease ICP

The primary purpose of administering mannitol to a patient with a subdural hematoma is to promote osmotic diuresis to decrease intracranial pressure (ICP). Mannitol is an osmotic diuretic that works by creating an osmotic gradient in the kidneys, which draws water out of tissues and into the bloodstream. This process not only reduces the volume of fluid in the brain, subsequently lowering ICP, but also helps to prevent secondary brain injury by improving perfusion and oxygenation. In the context of a subdural hematoma, where increased ICP can lead to significant neurological compromise, the administration of mannitol is critical in managing the patient's condition. It is also essential in preventing potential complications that can arise from elevated ICP, such as herniation or further brain damage. While mannitol does have roles related to intraocular pressure and vascular volume, its primary and most critical indication in this scenario is its effectiveness in reducing ICP. This therapeutic approach is vital to stabilizing patients with conditions that lead to elevated intracranial pressure.