The present disclosure relates to a medical catheter including an elongate catheter member (114) defining a longitudinal axis and having a proximal end, a distal end, an outer wall (128), and first (130) and second (132) internal lumens. The outer wall of the catheter member includes a first opening (142A) in fluid communication with the first internal lumen to facilitate the establishment of a first flow stream, and a second opening (142B) in fluid communication with the second internal lumen to facilitate the establishment of a second flow stream. Each of the first and second openings includes proximal (152A) and distal (154A) tapered portions that are connected by an intermediate portion having a constant transverse dimension. The configurations, dimensions, and positioning of the first and second openings optimizes separation of the first flow stream from the second flow stream in order to reduce the likelihood of recirculation between the first and second internal lumens.
