Final answer:
Mannitol reduces intracranial pressure in a patient with a head injury through osmotic diuresis, which draws excess fluid out of the brain into the bloodstream.
Step-by-step explanation:
A patient with a head injury is to receive mannitol at a dose of 0.5 grams/kg every 4-6 hours. The action of mannitol that reduces intracranial pressure (ICP) is Option 4: Osmotic diuresis. Osmotic diuretics like mannitol promote water loss by osmosis, which can help to decrease brain swelling and reduce ICP. Mannitol works by drawing fluid out of the brain and into the bloodstream, effectively reducing the total volume of fluid in the brain, thereby lowering the ICP. This osmotic effect is crucial in cases where the brain is at risk of damage due to increased pressure within the skull.
The drug mannitol is an osmotic diuretic that is used to reduce intracranial pressure (ICP) in patients with head injuries. It works by promoting water loss through osmosis. When mannitol is administered, it creates an osmotic gradient that draws water out of the brain tissue, reducing brain swelling and ICP. Therefore, the correct answer is option 4: Osmotic diuresis