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 spaced intervals of use , and non - use of a catheter while in place in the patient &# 39 ; 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 .