A medical apparatus generally includes a housing that translatably supports a grasping member and a motion control mechanism that is disengagable to permit motion of the grasping member relative to the housing. The housing is configured to support a flow inhibiting instrument when the grasping member is disposed in a retracted position. As such, the medical apparatus facilitates effective blockage of venous outflow from a hemodialysis access structure. In addition, the grasping member translates to a receiving position in which various vascular instruments may be inserted into the grasping member and to a holding position in which the grasping member firmly grasps the instrument. By holding the end of the apparatus opposite the instrument, a practitioner may position his or her hands outside of a medical imaging field and thereby reduce radiation exposure to the hands.
