Apparatus for use in dialyzing a patient, the apparatus comprising:a hemodialysis catheter comprising: an elongated body having a proximal end and a distal end, wherein the distal end terminates in a substantially planar distal end surface；first and second lumens extending from the proximal end of the elongated body to the distal end of the elongated body, wherein the first and second lumens terminate on the substantially planar distal end surface in first and second mouths, respectively, arranged in side-by-side configuration, and further wherein the first and second lumens are separated by a septum； andfirst and second longitudinal slots formed in the distal end of the elongated body and communicating with the interiors of the first and second lumens, respectively, the first and second longitudinal slots opening on the substantially planar distal end surface；wherein the first and second longitudinal slots each has a length and a width, relative to the dimensions of the first and second lumens and the rate of blood flow to be passed through the hemodialysis catheter, such that (i) when a given lumen is to be used for a return function, the primary blood flow will exit the mouth of that lumen, and (ii) when a given lumen is to be used for a suction function, the primary blood flow will enter the proximal end of the longitudinal slot associated with that lumen, whereby to minimize undesirable recirculation of dialyzed blood.
