A single use delivery device is disclosed having a manually deformable liquid container defining an inner chamber, the container having a distal end, a body, a proximal end, and an outlet on the distal end; a tip projecting from the outlet on the distal end of the container, the tip in fluid communication with the inner chamber of the container; and a primer element for removing one or more air bubbles from the chamber, said primer element being attached to and in fluid communication with the deformable container. A method of administering a fluid to or flushing a vascular access device using a single use pre-filled delivery device as described herein is also disclosed.