Intravenous (IV) simply means “within a vein.” IV therapy is a treatment that infuses fluids, medications, blood, or blood products into a vein for treatment of a patient (Figure 1-1). It permits accurate dosing and a swift effect of the substance infused. IV therapy is used to administer fluids, drugs, and nutrients when a patient cannot take these items orally. The rapid effect of fluids delivered directly into the bloodstream is necessary during emergencies or other critical-care situations in which medications are needed. However, the results can be fatal if the wrong medication or dosage is given.

Current IV therapy is less than 100 years old. Yet, it was known as early as the 1600s that medications could be injected into a vein. Because of a lack of understanding about sterility, infection control, and other scientific methods, original attempts to deliver IV fluids and drugs met with little success. The greatest advance in drugs, equipment, and procedures has occurred in the past 25 years. The practice and regulation surrounding IV therapy continues to evolve.