Which of the following might be a complication of using mannitol in a traumatic brain injury patient?

Mannitol is an osmotic diuretic often used in the management of traumatic brain injury to help reduce intracranial pressure by drawing fluid out of the brain tissue and into the bloodstream. One of the primary effects of administering mannitol is the expansion of blood volume, as it increases plasma osmolarity and encourages fluid to move from the interstitial space into the vascular compartment.

When mannitol is used in appropriate dosages, its expected outcome is to lower intracranial pressure. However, complications can arise, particularly in patients with traumatic brain injury, leading to alterations in blood pressure. If mannitol causes a significant increase in blood volume and subsequent fluid shift, it may lead to an initial increase in blood pressure due to the increased volume, but this can be followed by diuresis, which may eventually decrease blood pressure as the body excretes the excess fluid over time.

Thus, in the context of mannitol administration for a traumatic brain injury patient, lower blood pressure can occur as a complication due to fluid shifts and the osmotic effect of the medication. This highlights the importance of close monitoring of vital signs, including blood pressure and fluid status, during the administration of mannitol.