Which substance is known to momentarily increase blood pressure?

Mannitol is known to momentarily increase blood pressure due to its osmotic properties. As an osmotic diuretic, mannitol draws water into the vascular space, increasing the volume of blood in circulation. This temporary increase in blood volume elevates the blood pressure, making it effective in situations such as reducing intracranial pressure or managing acute renal failure.

In contrast, sodium typically influences blood pressure in the longer term through its role in fluid retention, while potassium is more associated with cardiac function and can lead to complications if levels are too high or too low. Dextrose, while providing energy, does not significantly impact blood pressure like mannitol does. This distinction makes mannitol the most relevant choice for momentarily increasing blood pressure.