Over this the tracheal dilators (blue) are passed in order, gradually dilating the incision to accommodate the appropriately sized tracheostomy tube. Plenty of lubricating jelly is applied to each dilator, and they are passed down the tract with a twisting motion. Only moderate downward force is applied. If the dilator does not pass easily, return to the previous smaller dilator and ensure it passes freely and easily. Often it is the skin that impedes progress, and the incision has to be slightly widened with the scalpel
Each size of tracheostomy tube has a corresponding dilator size (see the manufacturers instructions), and this should pass freely and easily into the trachea before attempting to insert the tracheostomy tube.