Abstract: An obturator is provided which allows for placing and withdrawing of a single catheter obturator over an extended period of time so as to allow speed intervals of use, and non-use of a catheter while in place in the patient's skin, while at the same time doing away with cumbersome, costly and time consuming administration and maintenance of saline and heparin locks. The device feeds the obturator in place for occluding the catheter lumen, when no fluids are being administered to the patient, and then may be retracted to a position allowing fluid feed through a supply tube connection to the catheter. The device includes a coating on the obturator rod which swells in contact with aqueous fluids to seal completely the catheter lumen which coating includes heparin to prevent clotting. Moreover, the entire internal functioning arrangement remains sterile during the entire period of use, thus avoiding infection.