Abstract: A vent tube is disclosed which has improved resilient characteristics and heparinized poly-tetrafluoroethylene inner surface to prevent clotting of blood passing through it as it drains serious fluids and blood from middle ear to the exterior of the body. The substrate is comprised of a cross-linked polysiloxane resin of a molecular weight of at least 10,000 units. The inner lining of the laminar item is comprised of a layer coating of tetrafluoro polyethylene having a thickness of 2 to 10 mils and impregnated with an anticoagulant at or near its surface.