Expandable obturator and catheter assembly including same

摘要

An oburator includes a solid substantially stiff rod of a nonhydrophilic polymer coated with a layer of a hydrophilic polyurethane which may have an antithrombogenic agent bulk distributing therein. When the hydrophilic polyurethane comes into contact with an aqueous liquid such as water, saline or a body fluid, it absorbs the liquid and expands thereby enlarging the diameter of the obturator. Another aspect of the invention is an assembly of a catheter and the obturator of the invention. When the obturator is emplaced in the catheter and brought into contact with a liquid, it expands, releases the antithrombogenic agent and contacts the lumen wall of the catheter thereby forming a seal which prevents backflow of a body fluid.