Intravenous

Intravenous refers to the administration of substances directly into a vein. Intravenous therapy provides rapid systemic delivery and is used when a quick onset or precise dosing is required, when oral administration is not possible, or for long-term or continuous infusion needs.

IV access can be peripheral or central. A peripheral IV uses a cannula inserted into a small vein in the arm or hand. Central venous access devices include central venous catheters, peripherally inserted central catheters (PICC lines), implanted ports, and tunneled catheters, which are used for long-term therapy, irritant medications, or high-volume infusions. IV administration can be structured as continuous infusion, intermittent infusion (piggyback), or IV push/bolus dosing.

Solutions and medications given by IV may include crystalloids (such as normal saline or lactated Ringer’s), dextrose solutions, and colloids, as well as blood products. In some cases, nutrition is provided intravenously (parenteral nutrition) when oral intake is not feasible. IV therapy requires careful preparation and monitoring to ensure compatibility and proper dosing.

Insertion and care require aseptic technique and appropriate equipment, including cannulas, catheters, tubing, and controllers. Infusion rates are adjusted by clinicians, and sites are regularly inspected for signs of infection, irritation, or infiltration.

Risks and complications can include infiltration or extravasation, phlebitis, infection or catheter-related bloodstream infection, air embolism, occlusion or thrombosis, fluid overload, electrolyte disturbances, and drug incompatibilities. Proper selection of access, meticulous technique, and ongoing monitoring minimize these risks.

Historically, intravenous therapy advanced in the 19th century, with early saline infusions used to treat cholera in the 1830s, leading to modern IV practice and devices.