Why would you need an IV?

The number one reason that I would think of, is due to dehydration. Then again it my depend on why you need the IV in the first place.

IV stands for intra venous, which means into the vein. IV's are routinely started on most ER patients for the following reasons; to obtain blood for laboratory test, to administer medications needed quickly in the body , or to replace vascular volume due to hypotension (low blood pressure).