According to the invention, a fluid exchange catheter is provided, which catheter has a proximal end and a distal end, and comprises an outer lumen having a proximal end adapted for fluid infusion and a distal end having a closed shape, and at least one inner lumen having a proximal end adapted for fluid aspiration and a distal end being arranged inside the outer lumen remote from the distal end of the outer lumen, wherein a lumen wall of the outer lumen forms a distal wall portion at the distal end of the outer lumen, the distal wall portion of the outer lumen comprising at least one lumen opening in the lumen wall, and wherein the distal end of the inner lumen comprises at least one lumen opening in the lumen wall, and wherein the at least one lumen opening in the lumen wall of the at least one inner lumen is larger than the at least one lumen opening in the lumen wall of the outer lumen. Furthermore, a process for unblocking such a fluid exchange catheter is provided.
