What does the term "extravasation" refer to?

The term "extravasation" specifically refers to the process where a substance, typically a fluid such as blood or medication, leaks out of its normal vessel and into the surrounding tissues. This can occur with intravenous infusions when the fluid leaks into the interstitial space instead of remaining within the vascular system. The event can lead to various complications, such as tissue swelling, pain, or even tissue damage, depending on the nature of the extravasated substance. Understanding this term is essential, especially in medical settings, where monitoring intravenous lines and recognizing the signs of extravasation can significantly affect patient outcomes.

The other options represent different physiological processes: the movement of fluids between cells pertains to osmosis and cellular hydration; inflammation of tissues relates to the body's response to injury or infection; and the formation of new blood vessels describes angiogenesis, a crucial process in healing and growth responses. None of these accurately capture the specific definition and implications of extravasation.