What is extravasation?

Extravasation specifically refers to the leakage of intravenous (IV) medications, particularly vesicants, into the surrounding subdermal tissues rather than staying within the intended vascular compartment. Vesicants are agents that can cause significant irritation or damage to tissues when they escape the vein. This can lead to complications such as pain, swelling, and tissue necrosis if not managed promptly.

The other options do not accurately define extravasation. The reabsorption of fluids into circulation refers to a different physiological process and does not involve leakage of medications. A delayed allergic reaction pertains to immune responses and is unrelated to the injury caused by IV medications leaking from their intended path. The absorption of medication into fat tissues is also a different concept, usually related to how drugs are metabolized or stored in the body, rather than the mishap of an IV administration. Therefore, the answer that correctly identifies extravasation as the leaking of vesicant medications into surrounding tissues is the most accurate definition.