A medical catheter assembly is provided including an inner catheter member, where that inner catheter member includes a plurality of inner catheter lumens, and an outer sheath with at least one patent sheath lumen. The inner catheter is slidably disposed through a length of the at least one patent sheath lumen in a manner providing a substantially sealing contact between an exterior surface of the inner catheter and an inward surface of the at least one patent sheath lumen. A first of the plurality of inner catheter lumens includes a plurality of apertures to the exterior surface of the inner catheter, and a second of the plurality of inner catheter lumens includes at least one distal end-tip opening. A method of using the assembly is also provided.
