What are the expected effects of mannitol when treating increased intracranial pressure (ICP)?

Mannitol is an osmotic diuretic that is commonly used to treat conditions associated with increased intracranial pressure (ICP), such as traumatic brain injury or cerebral edema. The mechanism of action involves drawing fluid out of the brain tissue and into the bloodstream. This helps to decrease the volume of fluid in the cranial cavity, effectively lowering the pressure within the skull. Thus, the primary and expected effect of mannitol in this context is a reduction in ICP, making option B the correct choice.

In addition to its role in reducing ICP, mannitol can have other effects on different physiological parameters, but those are secondary to its primary indication. For example, it may impact serum electrolyte levels or urine output but does not directly lead to improved pulse rate, increased potassium levels, or reduced muscle tension, which are not typical outcomes associated with its use in managing increased ICP.