Abstract "Catheter Assembly" The present invention relates to a catheter assembly comprising a catheter hub having a chamber therein, the catheter hub having a distal end and a proximal end, the catheter hub being capable of being connected. at its proximal end to a device for infusing or withdrawing fluids to or from the chamber within the catheter hub； a hollow tubular catheter having a proximal end and a distal end, the catheter being connected at its proximal end to the distal end of the catheter hub, the interior of the catheter opening into the chamber within the catheter hub； the needle having a sharp needle tip in the ready position the needle extending through the chamber in the catheter hub and the needle tip catheter extending beyond the distal end of the catheter； a hollow extension tube having a distal end and a proximal end, an extension tube being connected at its distal end to the catheter hub between the proximal and distal ends thereof, an extension tube opening at its distal end within the chamber within the catheter hub, an extension tube capable of being connected at its proximal end to a device for infusing fluid into the chamber within the catheter hub； a valve assembly disposed within the catheter hub chamber, a valve assembly comprising a first valve member that closes the distal end of the extension tube and capable of being opened under the action of a pressurized fluid within the extension tube ； and a second valve member preventing fluid flow through the chamber to or from the proximal end of the catheter hub, the second valve member being a two-way valve and capable of being open to allow fluid flow through the catheter hub. chamber in the catheter hub not only in the proximal direction but also in the distal direction. A needle guard assembly is also provided. 1/1resumo “conjunto de cateter” a presente invenção se refere a um conjunto de cateter que compreende um cubo de cateter tendo uma câmara no mesmo, o cubo de cateter tendo uma ex
