A cannula (; from Latin "little reed"; plural cannulae or cannulas) is a tube that can be inserted into the body, often for the delivery or removal of fluid or for the gathering of samples. In simple terms, a cannula can surround the inner or outer surfaces of a trocar needle thus extending the effective needle length by at least half the length of the original needle. It is also called an intravenous (IV) cannula. Its size mainly ranges from 14 to 24 gauge. Different-sized cannula have different colours as coded.
Decannulation is the permanent removal of a cannula (extubation), especially of a tracheostomy cannula, once a physician determines it is no longer needed for breathing.