infiltration

Infiltration is the diffusion or accumulation (in a tissue or cells) of foreign substances in amounts excess of the normal. The material collected in those tissues or cells is called infiltrate. Definitions of infiltration As part of a disease process, infiltration is sometimes used to define the invasion of cancer cells into the underlying matrix or the blood vessels. Similarly, the term may describe the deposition of amyloid protein. During leukocyte extravasation, white blood cells move in response to cytokines from within the blood, into the diseased or infected tissues, usually in the same direction as a chemical gradient, in a process called chemotaxis. The presence of lymphocytes in tissue in greater than normal numbers is likewise called infiltration. As part of medical intervention, local anaesthetics may be injected at more than one point so as to infiltrate an area prior to a surgical procedure. However, the term may also apply to unintended iatrogenic leakage of fluids from phlebotomy or intravenous drug delivery procedures, a process also known as extravasation or "tissuing". Causes Infiltration may be caused by: Puncture of distal vein wall during venipuncture Puncture of any portion of the vein wall by mechanical friction from the catheter/needle cannula Dislodgement of the catheter/needle cannula from the intima of the vein which may be a result of a poorly secured IV device or inappropriate choice of venous site to puncture. Improper cannula size or excessive delivery rate of the fluid