IV Cannula is a tube which can be inserted into the body, at times for the delivery or removal of fluid or for gathering data. To understand it in a simpler way, a IV Cannula can surround the inner or outer surfaces of a trocar needle therefore extending needle connects to a vein by half or more of the length of the introducer. Decannulation is the lasting removal of a IV Cannula (extubation), particularly of a tracheostomy cannula, once a medical professional determines it is no longer needed for breathing.