intravenous infusion, 1. a solution administered into a vein through an infusion set that includes a plastic or glass vacuum bottle or bag containing the solution and tubing connecting the bottle to a catheter or a needle in the patient’s vein. 2. the process of administering a solution intravenously. Swelling of the limb around and distal to the site of injection may indicate that the tip of the catheter or needle is in the subcutaneous tissue and not in the vein. The fluid may be infiltrating the tissue spaces. It should be withdrawn and the limb elevated. Redness, swelling, heat, and pain around the vein at the site of injection or proximal to it may indicate thrombophlebitis. The infusion should be discontinued and the inflammatory condition treated. The infusion is usually begun again at another site. See also venipuncture.
