A<unk>  is the method of clearing intravenous lines (IVs), central lines or arterial lines of any medicine or other perishable liquids to keep the lines (tubes) and entry area clean and sterile. Typically in<unk> ing an intravenous cannula, a 5 - 10ml syringe of<unk>  is emptied into the medication port of the cannula's connecting hub after insertion of the cannula.Please note - a 10ml syringe needs to be used to ensure correct pressure, whether you are giving 5ml or 10ml Blood left in the cannula or hub can lead to clots forming and blocking the cannula.<unk> ing is required before a drip is connected to ensure that the IV is still patent.<unk> ing is also used after medications are delivered by the medication port to ensure all the drug is delivered fully. If multiple medications are given through the same line,<unk> ing can be used in between drugs to ensure that the medicines won't react. This is especially important if complex regimes of intravenous medication is used such as in chemotherapy.<unk> ing with<unk>  should be painless if the cannula is in its proper place, although if the<unk>  is not warmed there may be a cold sensation running up the vein. A painful<unk>  may indicate tissuing or phlebitis and is an indication that the cannula should be relocated. Solutions other than normal<unk>  may be used. Heparinised<unk>  may be used in<unk> ing arterial lines, to prevent clotting and blockage of the line. When syringes are used to perform a<unk> , it is important that the syringe not be reused for multiple patients, even though direct contact with the patient does not normally occur. In angiography, a<unk>  is used to improve the dispersion of contrast media before imaging, This can prevent streak artefact due to concentrated bands of contrast media in the superior vena cava and brachiocephalic vein.<unk> ing can also increase hydration within contrast media, thus reducing the risk of contrast induced nephro toxicity.
Saline flush
Perfusion
Volume expander
Depot injection
Infiltration analgesia
Decompression 
Emperipolesis
Osmotic dilator